tag:blogger.com,1999:blog-197809262024-03-06T23:40:04.271-08:00baudline signal analyzerA spectrum analysis scientific visualization tool.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.comBlogger31125tag:blogger.com,1999:blog-19780926.post-81268879315641518452013-05-09T14:44:00.000-07:002013-05-10T12:24:36.196-07:00setiQuest GOES-11The <a href="http://setiquest.org/wiki/index.php/ATA">Allen Telescope Array</a> (ATA) collected an 8.7 MHz wide chunk of spectrum from the NOAA GOES-11 weather satellite at 1692 MHz back in September 2010. The GOES-11 satellite has since been decommissioned and replaced by GOES-15 but its <b>glorious signal</b> lives on in the <a href="http://setiquest.org/wiki/index.php/SetiQuest_Data">setiQuest data archive</a>. This particular quadrature dataset has a duration of 532 seconds and is 8.9 GB in size. The <a href="http://www.baudline.com/">baudline signal analyzer</a> is going to take a look at some of the signals in this GOES-11 dataset.<br />
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There are an incredible number of signals hidden in this dataset. We're going to zoom in, browse around, measure, and identify a few of them. For fun I'm going to take the approach of doing a <b>blind analysis</b> of the GOES-11 signal data. This means that I'm <b>not</b> going to use the Internet to determine any signal features such as modulation types and baud rates. No external help. Just baudline. Let's go ...<br />
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The <a href="http://baudline.com/manual/average.html#average">average spectral plot</a> above is a map of where we're going to zoom in and analyze. The blue lines represent wideband regions that will be focused on in different sections of this analysis. The red dots are representative of individual signals that will analyzed in depth. We begin the analysis on the left side of the spectrum and will work our way to the right.<br />
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<span style="font-size: large;">-2000 ... +100 kHz</span><br />
Here is the chunk of spectrum from the first blue line. Tip: use the size and position of baudline's lower scroll bar to determine the
frequency resolution and position in relation to the main spectrogram/average map. In this example notice how the size and position of the scroll bar match the size and position of the first blue line.<br />
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It looks like a lot is going on here but in fact there are only two unique signals. Everything else is caused by mixing problems. Let's try to sort things out by making some frequency measurements.<br />
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The two red dots represent the signal that we'll being analyzing in depth next. The orange, yellow, and blue horizontal lines represent the distance between the constant features seen in the previous spectrogram.<br />
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orange = 294400 Hz<br />
yellow = 258133 Hz<br />
blue = 36267 Hz<br />
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Here are some interesting mathematical relationships:<br />
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orange = yellow + blue<br />
yellow / orange = 7 / 8<br />
orange + yellow = width of the main central lobe<br />
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The 7/8 ratio is very unusual as is the coupling of the two different signal types. Now let's zoom into the time domain and check out the two signals marked by the red dots.<br />
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This level of signal resolution clearly shows six Frequency Shift Keying (<a href="http://baudline.com/manual/glossary.html#FSK">FSK</a>) modulated signals. Notice that the mark and space frequencies on the left side are inverted from the right side. Also the two FSK's on the outer edges are wider with roughly twice the frequency delta between mark and space. To get a better view here is a zoomed in spectrogram extract of them:<br />
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Baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity helper bars</a> measure a bit rate of 9600 bits/second. The multiple FSK signals have different frequency widths but they have the same bit stream. This makes them the same base signal. One of them has been stretched by an unknown process.<br />
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Above are the stacked average spectrum of the wider FSK and the narrower FSK signals. The upper FSK has a measured mark/space delta of 20 kHz and the lower has a mark-space delta of 8 kHz. This 20 / 8 = 2.5 ratio is far enough away from a factor of 2 that something else other than basic harmonic mixing is occurring.<br />
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What is stranger is that the spectral shapes look completely different. How and why is a mystery. They are the same signal. Straight alias mixing should not be able to do this. Here are some modulation measurements for both FSK signals:<br />
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<b>modulation type:</b> FSK<br />
<b>spectral width:</b> 30 and 16 kHz<br />
<b>mark-space delta:</b> 20 and 8 kHz<br />
<b>bits / symbol:</b> 1 <br />
<b>symbol rate:</b> 9600 symbols / sec <br />
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Note that when the bits / symbol parameter equals 1, the symbol rate is equal to the baud rate. So both of these FSK signals have a 9600 bit/sec baud rate.<br />
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<span style="font-size: large;">-1000 kHz</span><br />
Next let's look at the wide spectral hump that is in-between the FSK signals discussed previously. Centered at -1000 kHz, the red dot in the following image highlights our target signal. <br />
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Sharp filters keep the FSK signals from impairing this signal of interest. Carrier lock with baudline's new IQ display:<br />
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The two bright points are Phase Shift Keying (<a href="http://baudline.com/manual/glossary.html#PSK">PSK</a>) symbols that are 180° out of phase. This signal is called Binary Phase Shift Keying (BPSK). Here are some modulation measurements:<br />
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<b>carrier frequency:</b> 1692 + 0.999991 MHz<br />
<b>modulation type:</b> BPSK<br />
<b>spectral width:</b> 350 kHz at -6 dB<br />
<b>bits / symbol:</b> 1<br />
<b>symbol rate:</b> 293884.01 symbols / sec<br />
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For PSK modulations, the symbol rate being roughly equal to the spectral width is a good measurement sanity check. An interesting observation is that the accurate BPSK symbol rate measurement is approximate to the less accurate orange delta Hz measurement bar that was discussed at the beginning of this section. An unknown mixing process must be at work for the BPSK symbol rate to be connected to the frequency positions of the FSK images. This is very unusual.<br />
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Next let's focus on the transient horizontal bursts that are overlaid on top of this BPSK signal. There are more than eight bursts and they appear to have random durations and spacing. The duration of the bursts range from less than a second to more than a minute. It's interesting to note that the IQ constellation doesn't change when mousing over the bursts. The gain fluctuation in the spectrogram frequency space is quite dramatic yet the gain, phase angle, and jitter all remain constant in the IQ space. How is this possible?<br />
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To answer that question let's zoom into the time axis with a smaller FFT size.<br />
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There is significant structure here. Click the image for more detail. The middle vertical line is one of the FSK artifacts. Baudline's periodicity bars show that these horizontal burst groups have a 56 ms periodicity. Each burst is 48 ms in duration followed by a 8 ms off time. Zooming deeper into the spectrogram shows a highly repetitive spectral pattern. An autocorrelation plot verifies this.<br />
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The primary lag in red represents a periodicity of 0.3845 ms. Note that the rightmost red line has been folded by <a href="http://www.baudline.com/manual/glossary.html#aliasing">aliasing</a>. The secondary lag in yellow is 1.7358 ms with 0.3845 ms sidebands. The calculation 1.7358 ms / 0.3845 = 4.514 is an unusual ratio. Using the BPSK symbol rate, the two lags translate to 113.00 (red) and 510.12 (yellow) symbols. The sidebands and the strange ratio suggests two possible explanations: that the secondary lag is being time modulated by the primary lag or that each transient burst consists of a repeating bit pattern that has two periodicities. How to construct either option is not obvious. There must be a simpler explanation.<br />
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Since GOES-11 is a weather satellite these bursts may signify blank or repeating image lines. An idle pattern or training sequence is another option but the complexity of the signal makes this unlikely. Demodulating the bits would answer this question definitively but that is a project for another blog post. <br />
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<span style="font-size: large;">+1800 <span style="font-size: large;">...</span> +2900 kHz</span><br />
Now we're going to jump to some signals of interest on the right side of the main spectrum (the 2nd blue line).<br />
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First we'll look at the strong vertical signal on the left side and then we'll dive in and take a look at some of the many signals shown in the right half.<br />
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<span style="font-size: large;">+2000 kHz</span><br />
The average spectrum of the strong vertical signal on the left.<br />
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Notice the middle strong tone and the mirror image spectral humps. This what happens when the transmission carrier in not suppressed. The delta frequency between the strong carrier tone and one of the spikes on the hump is 2 kHz. The spectral width of the one of the main humps is 4 kHz but the harmonics of this modulation stretch out to about 500 kHz wide. This is not an effective use of the available bandwidth.<br />
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The IQ display can be used to determine the modulation type.<br />
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Notice how the two symbols are offset from the origin. This is caused by the non-suppressed carrier. With some decimation, down mixing, carrier suppression, and selecting either the upper or lower sidebands (USB or <a href="http://www.baudline.com/manual/glossary.html#LSB">LSB</a>) the IQ plot becomes:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrx9gfCKtcTCE5T2hRHmH1d_0Up9DbGlWxNXw9e7BuKd0g33VtbUO591eSVXYLNXmo4l5wFhZ_8DOsleMVSimZ-1qJuOmDWZp2r_vfCl9vecu0dxK00eN2A3n4AzMmdFP9fgfD/s1600/IQ+carrier-suppressed+BPSK++2+MHz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrx9gfCKtcTCE5T2hRHmH1d_0Up9DbGlWxNXw9e7BuKd0g33VtbUO591eSVXYLNXmo4l5wFhZ_8DOsleMVSimZ-1qJuOmDWZp2r_vfCl9vecu0dxK00eN2A3n4AzMmdFP9fgfD/s320/IQ+carrier-suppressed+BPSK++2+MHz.png" height="320" width="309" /></a></div>
<br />
Here are some modulation measurements:<br />
<br />
<b>carrier frequency:</b> 1692 + 1.998614 MHz<br />
<b>modulation type:</b> BPSK<br />
<b>spectral width:</b> 4 kHz of <a href="http://www.baudline.com/manual/glossary.html#SSB">SSB</a><br />
<b>bits / symbol:</b> 1<br />
<b>symbol rate:</b> 4000.025 symbols / sec<br />
<br />
<br />
<span style="font-size: large;">+2225 ... +2750 kHz</span><br />
Here is a spectrogram of the many signals section (the 3rd blue line):<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhieASh_IQn3tC0Jg1hOl49njGnF0FraBp_Rr-vtzw3C4VOgzCfJ9vajBQn_qyYeA4fsGl57fai4hjIosd-YqzHIZPiOioxfFGDhyzO-AlWzdn3aRLh8MDXr71vzeESH5URmAG-/s1600/spectrogram++2.5+MHz+many.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhieASh_IQn3tC0Jg1hOl49njGnF0FraBp_Rr-vtzw3C4VOgzCfJ9vajBQn_qyYeA4fsGl57fai4hjIosd-YqzHIZPiOioxfFGDhyzO-AlWzdn3aRLh8MDXr71vzeESH5URmAG-/s400/spectrogram++2.5+MHz+many.png" height="376" width="400" /></a></div>
<br />
It is full of signals. Thousands and thousands of signals. Let's start on the left and zoom into several of the interesting sections.<br />
<br />
I call this next section centered at +2250 kHz "snow" because that is what it looks like. The deeper you zoom into both axes the more signals you see. Very high signal density. It is like a whole world unto itself.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_1Pw2MGpZ033wJ4C82VyotUVTr0H8wyNX-gnvmV_VasrBrlvESB7uFn5uv9HSfepA6aBZGsjtlrwnAA1gQlglwScBQ32pLFXIQCMqJapVRcHXXy7ri_5_ApsFjE5la2j-eO-R/s1600/spectrogram++2.25+MHz+snow.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_1Pw2MGpZ033wJ4C82VyotUVTr0H8wyNX-gnvmV_VasrBrlvESB7uFn5uv9HSfepA6aBZGsjtlrwnAA1gQlglwScBQ32pLFXIQCMqJapVRcHXXy7ri_5_ApsFjE5la2j-eO-R/s400/spectrogram++2.25+MHz+snow.png" height="376" width="400" /></a></div>
<br />
Click the image above to see the fine details. Even at high zoom levels the signals are not well defined. The blips look like very short duration tone bursts, some look like fuzzy snowflakes. It is like some mysterious process has shrunk down and squeezed together what you are about to see in the following sections.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhk3vzv-HsBTjiaqSRiypCPsfQkg5dcD6tqf0z9KfvAa98JRj1tGnHjYsg1-_E_UFn-DcFKh5sfZ_2aXtU_9xZexlSHadYG5f3urwawG1UpDI8WYkyKeIG-s7fHeYWxgzxEQiwq/s1600/spectrogram+many1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhk3vzv-HsBTjiaqSRiypCPsfQkg5dcD6tqf0z9KfvAa98JRj1tGnHjYsg1-_E_UFn-DcFKh5sfZ_2aXtU_9xZexlSHadYG5f3urwawG1UpDI8WYkyKeIG-s7fHeYWxgzxEQiwq/s400/spectrogram+many1.png" height="376" width="400" /></a></div>
<br />
There are many signals of various durations, sizes, and shapes. The signals look like short modulated packet bursts of data. Most of the signals appear to be lined up in frequency slots. This is known as Frequency Division Multiplexing (<a href="http://www.baudline.com/manual/glossary.html#FDM">FDM</a>). Many signals appear to begin transmission at a common 30 second time slot and to a lesser extent at 10 second intervals. This behavior doesn't apply to all of the signals but there is a great deal of organization.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCgGFYU0mErlCxmZR2LnsC9Q7vBsV3C5ZPRaPoIYVUIwF0mA-SBQlRkhz5fmvNQabQI-BOkxHg88Md_isGW6E-qGi8XScQnOARDMJclWuNyh3kDP0YaybJ2N51Y4dzROAhL5BF/s1600/spectrogram+many2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCgGFYU0mErlCxmZR2LnsC9Q7vBsV3C5ZPRaPoIYVUIwF0mA-SBQlRkhz5fmvNQabQI-BOkxHg88Md_isGW6E-qGi8XScQnOARDMJclWuNyh3kDP0YaybJ2N51Y4dzROAhL5BF/s400/spectrogram+many2.png" height="376" width="400" /></a></div>
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<br />
The image above is a different section that is zoomed in a bit. Some of the signals have strong sidebands and some don't which suggests that there are multiple transmitters involved.<br />
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<br />
<span style="font-size: large;">+2422 kHz </span><br />
From the right side of the previous image, here is a deeper zoom into the frequency axis.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5vcg59UhbAV09f4v6E309Y9zefMlrBgGA8gZIjnV5EOfDeeGLQvSwjfQVfA1G3GfwbnYWzKp6Y5qlNJrdMC_-AS12RLja4Rde4Ra1y2WTpow1vBDgMCnzXwbKP_Sbd-XMhIU7/s1600/spectrogram+many+doppler.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5vcg59UhbAV09f4v6E309Y9zefMlrBgGA8gZIjnV5EOfDeeGLQvSwjfQVfA1G3GfwbnYWzKp6Y5qlNJrdMC_-AS12RLja4Rde4Ra1y2WTpow1vBDgMCnzXwbKP_Sbd-XMhIU7/s400/spectrogram+many+doppler.png" height="376" width="400" /></a></div>
<br />
Four modulated packets are visible. Each packet has a strong central carrier that is the source of the upper and lower sideband symmetry. On closer inspection the top two packets have a slight drift to the right and to the left. This could be due to Doppler or it could be due to a non-stable and slowly drifting transmitter clock.<br />
<br />
Slicing through the middle of the spectrogram is a fast moving object that is being Doppler drifted. The slope is straight at the top (overhead) and then becomes curved as it recedes (away). This behavior follows the expected Doppler flyby curve shape. The measured drift rate for the top "overhead" section is 90.6 Hz / 118.1 seconds = 0.767 Hz/sec. The lower "away" section is slightly curved which makes it difficult to measure accurately. An approximate measurement of the lower drift rate is 83.3 Hz / 161.7 seconds = 0.515 Hz/sec. This slow moving signal looks to be <a href="http://baudline.com/manual/glossary.html#AM">AM</a> modulated with a carrier-to-sideband delta of 10 Hz. If this was a modulated On Off Key (OOK) data signal then the baud rate would be 10 bits/sec.<br />
<br />
Here is the lower sideband IQ plot of the last modulated packet.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAoSChA08ty3U3JnrHADUuL-oAPOOwcT1j3UJ6k1kpMLTNwk1vRvAC2cV_IBeyq4m2NIZHzXwkyYlCp4uRPxyFgDUm2t7rOq2zft2Blirt349ih07LLp8heZlQBBX_sq03M_CL/s1600/IQ+BPSK++2.4215+MHz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAoSChA08ty3U3JnrHADUuL-oAPOOwcT1j3UJ6k1kpMLTNwk1vRvAC2cV_IBeyq4m2NIZHzXwkyYlCp4uRPxyFgDUm2t7rOq2zft2Blirt349ih07LLp8heZlQBBX_sq03M_CL/s320/IQ+BPSK++2.4215+MHz.png" height="320" width="308" /></a></div>
<br />
This jittery constellation is BPSK. It looks different than the previous BPSK signal seen above. The extra jitter and other signal instabilities suggests a lower quality modulator / transmitter source.<br />
<br />
<b>carrier frequency:</b> 1692 + 2.421614 MHz<br />
<b>modulation type:</b> BPSK<br />
<b>spectral width:</b> 200 Hz of SSB<br />
<b>bits / symbol:</b> 1<br />
<b>symbol rate:</b> 200 symbols / sec<br />
<br />
<br />
<span style="font-size: large;">+2505.6 kHz</span><br />
Here is the spectrogram display of a nearby frequency.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6VPE7y-2OoQfrpztxJE5hEooLIowpCPTIx3rSWPA9BipGEbZUYgdVENXWeKFuNiEW6cModlbsKeEPWeYzo4a_FcMdMWigKujys9KIcGz7MzlcCzytSXq9qYaWR2nJc0IR2dCZ/s1600/spectro+8-PSK++2.5056+MHz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6VPE7y-2OoQfrpztxJE5hEooLIowpCPTIx3rSWPA9BipGEbZUYgdVENXWeKFuNiEW6cModlbsKeEPWeYzo4a_FcMdMWigKujys9KIcGz7MzlcCzytSXq9qYaWR2nJc0IR2dCZ/s400/spectro+8-PSK++2.5056+MHz.png" height="375" width="400" /></a></div>
<br />
<br />
Five packets are visible. Each packet begins with a brief tone and is then followed by what looks like a wider bandwidth modulation. Notice the modulation sidebands. Here is the <a href="http://baudline.com/manual/waveform.html#waveform">waveform</a> display of one of the packets. <br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgedodVZ6sJTxxK4n-S8V2LB_8eFGbLEq7RPg5rOc1LUf7bQplc6X2M0usnytG_sBfIBfIhaEHuSWqx8zh6WJghcsBYm_G4dM_CHa519ASFpreo8M563RfUpvBOuy0TJSdkMsOA/s1600/waveform+8-PSK++2.5056+MHz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgedodVZ6sJTxxK4n-S8V2LB_8eFGbLEq7RPg5rOc1LUf7bQplc6X2M0usnytG_sBfIBfIhaEHuSWqx8zh6WJghcsBYm_G4dM_CHa519ASFpreo8M563RfUpvBOuy0TJSdkMsOA/s400/waveform+8-PSK++2.5056+MHz.png" height="120" width="400" /></a></div>
<br />
Notice the constant envelope with many different types of phase shifts. Next, let's look at the IQ display.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiLJmUEM6pxelbceajQTElVxMVA51NXKE_aoH-g46uhzprcEW30aX-BlBiga0yZGdYohgY7kM0_EimM8oI9IOnI_t2Y3R37i9HyEtZn64n1JqsTryQXds2HvK-ePdS9jVipnrb/s1600/IQ+8-PSK++2.5056+MHz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiLJmUEM6pxelbceajQTElVxMVA51NXKE_aoH-g46uhzprcEW30aX-BlBiga0yZGdYohgY7kM0_EimM8oI9IOnI_t2Y3R37i9HyEtZn64n1JqsTryQXds2HvK-ePdS9jVipnrb/s320/IQ+8-PSK++2.5056+MHz.png" height="320" width="308" /></a></div>
<br />
This modulation is 8-PSK. Each of the eight symbols has it's own distinct phase (360° / 8 = 45°). In this modulation scheme a symbol encodes 3 bits of information (2^3 = 8).<br />
<br />
<b>carrier frequency:</b> 1692 + 2.505610 MHz<br />
<b>modulation type:</b> 8-PSK<br />
<b>spectral width:</b> 160 Hz at -6 dB<br />
<b>bits / symbol:</b> 3<br />
<b>symbol rate:</b> 150 symbols / sec<br />
<b>baud rate:</b> 450 bits / sec<br />
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<br />
<span style="font-size: large;">+2704 kHz</span><br />
What is this mysterious looking stuff next to the wide vertical line?<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgM5TzWt5-SzRxJpoYQsjpcFTlzAEYgSJoVDQbDU_yy6aavh1SFSP68oFd8Qb7mwdNtAEfvYRqx0287MCexBwDAIthDIYf0Yiz9PEHI0IF0HCDoJWaonDqW2qBZnwDlnz1usBaF/s1600/spectro+mysterious+stuff++2.7+MHz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgM5TzWt5-SzRxJpoYQsjpcFTlzAEYgSJoVDQbDU_yy6aavh1SFSP68oFd8Qb7mwdNtAEfvYRqx0287MCexBwDAIthDIYf0Yiz9PEHI0IF0HCDoJWaonDqW2qBZnwDlnz1usBaF/s400/spectro+mysterious+stuff++2.7+MHz.png" height="376" width="400" /></a></div>
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<br />
This particular signal is featured in the <a href="http://setiquest.org/forum/topic/evolution-vs-intelligent-design#comment-4029">found a DNA strand</a> comment on the setiQuest forum. We will be avoiding any erroneous time aliasing distortion here. Let's zoom into the time and frequency axes to get a better look.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWXvF-i5ntnPzdg8xnvzv_eWiDMdBN99gnLbEZnQflP_b9275cpMr3oBx1bgJkFJ-yDBbXstdCdPv1AOUnzWwzBdPyBET2BDn1otU2S6nqPu0Vqa1lWIZT4zAdNv90PdcASdHQ/s1600/spectro+FM+sine++2.704+MHz+out.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWXvF-i5ntnPzdg8xnvzv_eWiDMdBN99gnLbEZnQflP_b9275cpMr3oBx1bgJkFJ-yDBbXstdCdPv1AOUnzWwzBdPyBET2BDn1otU2S6nqPu0Vqa1lWIZT4zAdNv90PdcASdHQ/s400/spectro+FM+sine++2.704+MHz+out.png" height="376" width="400" /></a></div>
<br />
This looks like a harmonic power ramp up with the frequency carrier stabilizing after a half second. There are some faint noise-like data bursts interspersed in the middle.<br />
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Let's zoom into the time axis some more. <br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzMYZ6f2m_aEuupbSXhMRdShbVsZXlfoCjPjV-bDqmOCRao4WpGd1O1kKwFvUsic1QeGkPlFloO_xJmeiJtjnneymvgU5SEUTfiL-lI0piXbAqr7duv3elKc9BeYeESeLRRqMA/s1600/spectro+FM+sine++2.704+MHz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzMYZ6f2m_aEuupbSXhMRdShbVsZXlfoCjPjV-bDqmOCRao4WpGd1O1kKwFvUsic1QeGkPlFloO_xJmeiJtjnneymvgU5SEUTfiL-lI0piXbAqr7duv3elKc9BeYeESeLRRqMA/s400/spectro+FM+sine++2.704+MHz.png" height="376" width="400" /></a></div>
<br />
This signal is a sine carrier that is <a href="http://baudline.com/manual/glossary.html#FM">FM</a> modulated by a 71.4 Hz sine wave. The delta of the upper and lower modulation frequencies is about 1040 Hz.<br />
<br />
This signal looks and sounds a lot like the <a href="http://www.youtube.com/watch?v=wGUMcuCp9yY&hd=1">very strange "flying saucer" signal</a> that was discovered a couple years ago in the setiQuest data. The measured modulation parameters are slightly different but I wouldn't be surprised if it was generated by a similar mechanism, perhaps by spinning. Note that this signal's whimsical nickname is a reference to classic B-movie scifi sound effects. There is zero reason to believe that this signal is from a real flying saucer. UFO alert canceled.<br />
<br />
<br />
<span style="font-size: large;">+2725.7 kHz</span><br />
This next signal looked like a constant tone until zooming way into the frequency axis. The spectral resolution of this image is 0.521 Hz/bin.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrBhKfmKwACyjs906GO03aeRPm24gu3fVUvl7_Gq66gaC2VJYzPr5owIsNGXrruwxvorLZo5i32P7ETKFT3yCBry37F-5Roz8bjuD2q1Yo0VNmCBxX-y2k9HgNn2K-juh3LHTi/s1600/spectrogram+tone+dips+61.4Hz.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrBhKfmKwACyjs906GO03aeRPm24gu3fVUvl7_Gq66gaC2VJYzPr5owIsNGXrruwxvorLZo5i32P7ETKFT3yCBry37F-5Roz8bjuD2q1Yo0VNmCBxX-y2k9HgNn2K-juh3LHTi/s400/spectrogram+tone+dips+61.4Hz.png" height="376" width="400" /></a></div>
<br />
The tone dips are -15 Hz to the left. The repeating dips have a periodicity measurement of 61.4 seconds. The repetition timing is exact like clockwork. The whole structure is slowly drifting to the right at a 5.73 Hz / 523.3 seconds = +0.0109 Hz/sec rate. What it is and why it is doing this are unknown.<br />
<br />
<br />
<span style="font-size: large;">+3350 kHz</span><br />
This spectrogram from the far right of the dataset's spectrum is an example of a Doppler flyby.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivpELCbM2A91gHb6p9V09tKGdclvDTePL7D1AwDCGk295isW7MVZPBGF4kzHZKqTFgnC_A615tEazADf2ksGTtQnDh6jGPjIapsowcnzi9YBk4YSXXk2cWJPx6PTSwUnnKTAnw/s1600/spectrogram+LEO.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivpELCbM2A91gHb6p9V09tKGdclvDTePL7D1AwDCGk295isW7MVZPBGF4kzHZKqTFgnC_A615tEazADf2ksGTtQnDh6jGPjIapsowcnzi9YBk4YSXXk2cWJPx6PTSwUnnKTAnw/s400/spectrogram+LEO.png" height="376" width="400" /></a></div>
<br />
The top third of the curve is fairly straight and it represents an overhead position. The measured Doppler drift rate is 22200 Hz / 109.3 seconds = 203.1 Hz/sec. That is fast.<br />
<br />
The fainter middle section is curved and represents a transition.<br />
<br />
The lower third section still has a slight curve but it is beginning to straighten out. This motion represents that the object has transitioned to a receding (away) position. The measured Doppler drift rate is 5067 Hz / 102.9 seconds = 49.24 Hz/sec. <br />
<br />
No modulation is visible. This object is likely a fast moving Low Earth Orbit (LEO) satellite.<br />
<br />
Note that with judicious scaling, the basic shape of the Doppler curve above roughly matches the curve seen in the 8-PSK packets image. The scaling is off by a factor of 265X but the overhead and away transitions occur at about the same times. The two Doppler signals may be related by some extreme mixing artifacts.<br />
<br />
<br />
<span style="font-size: large;">Histogram</span><br />
The datasets in the setiQuest archive use signed 8-bit <a href="http://baudline.com/manual/glossary.html#quadrature">quadrature</a> samples. Below is the <a href="http://baudline.com/manual/histogram.html#histogram">histogram plot</a> of the I channel. The Q channel looks the same.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_M81cnTZQp_J6yOgs2I8sur18n-YaKJfVMF5UfCCvaU-yy5TB5jGvy93j1JW0aAohOwv5qatuv1FNq8GuSffpmjXt28TFX4R5jIl9J-H6Z9Yw1Dup_hEpr-0zIPH8Je_JoP_i/s1600/histogram.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_M81cnTZQp_J6yOgs2I8sur18n-YaKJfVMF5UfCCvaU-yy5TB5jGvy93j1JW0aAohOwv5qatuv1FNq8GuSffpmjXt28TFX4R5jIl9J-H6Z9Yw1Dup_hEpr-0zIPH8Je_JoP_i/s400/histogram.png" height="207" width="400" /></a></div>
<br />
The holes between every other bin is normal when 8-bit samples are viewed in 9-bit space (bins=512).<br />
<br />
The large number of spikes reveals a rounding problem. The alternating cadence is a spike every 2nd and then 3rd sample. Somewhere in the <a href="http://baudline.com/manual/glossary.html#ADC">ADC</a> --> beamformer --> data collection chain the higher bit samples are being poorly quantized down to 8-bits. This sort of error causes alias distortion.<br />
<br />
The spike at 0 is interesting as is the drop at the next sample value of 1. This signifies a truncation round to zero problem. It also will cause a DC offset.<br />
<br />
Only about 7 of the 8 bits are being used. There is plenty of sample headroom and clipping is not a potential problem. Not using 1 bit of resolution reduces <a href="http://baudline.com/manual/measurements.html#SINAD">SINAD</a> by 6 dB. Note that SINAD is related to SNR.<br />
<br />
For an informative and amusing look at other histogram problems take a look at the <a href="http://baudline.com/solutions/full_duplex/quantization.html">Quantization Shop of Horrors</a>.<br />
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<br />
<span style="font-size: large;">Conclusion</span><br />
This setiQuest GOES-11 dataset is a smorgasbord of signals. We saw FSK, BPSK, offset-BPSK, 8-PSK, and the "flying saucer" modulations with a drifting LEO thrown in for good measure. The mirror aliasing throughout the entire spectrum is troublesome. Either the ATA's <a href="http://baudline.com/manual/glossary.html#AGC">AGC</a> or the 8-bit quantization is likely to blame.<br />
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<span style="font-size: large;">Links</span><br />
<ul>
<li><a href="http://setiquest.org/forum/topic/baudline-analysis-goes-11">http://setiquest.org/forum/topic/baudline-analysis-goes-11</a></li>
<li><a href="http://setiquest.org/forum/topic/evolution-vs-intelligent-design#comment-4029">http://setiquest.org/forum/topic/evolution-vs-intelligent-design#comment-4029</a> </li>
<li><a href="http://www.youtube.com/watch?v=wGUMcuCp9yY">http://www.youtube.com/watch?v=wGUMcuCp9yY</a> </li>
</ul>
<ul>
</ul>
<span style="font-size: x-small;">Data licensed through <a href="http://seti.org/">SETI</a>.</span><br />
<span style="font-size: x-small;">Software licensed through <a href="http://sigblips.com/">SigBlips</a>.</span>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1tag:blogger.com,1999:blog-19780926.post-18356729170629799672012-11-30T16:22:00.002-08:002013-05-07T17:12:01.896-07:00setiQuest Voyager 1 redux<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTiGJCVI-xUu6dbIRuu4fLqTMXqa8EEo1a_tzjC8wPoq-7grFX6CGitct34gpRPF3cZudVV4UEZitBCb707ULAXIaTmfi7Ijo02TD3ukgY6tSMXAApEoW81CokOFV7N8B1FlkH/s1600/Voyager+small3.jpeg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTiGJCVI-xUu6dbIRuu4fLqTMXqa8EEo1a_tzjC8wPoq-7grFX6CGitct34gpRPF3cZudVV4UEZitBCb707ULAXIaTmfi7Ijo02TD3ukgY6tSMXAApEoW81CokOFV7N8B1FlkH/s1600/Voyager+small3.jpeg" /></a></div>
The NASA Voyager 1 probe has been spotted again at the <a href="http://setiquest.org/wiki/index.php/ATA">Allen Telescope Array</a> (ATA). This is fairly amazing since JPL is the only other group that can see Voyager and they use a much bigger telescope that's part of the Deep Space Network (DSN). The <a href="http://seti.org/">SETI Institute</a>'s Jane Jordon and Jon Richards were kind enough to send me this new Voyager data so that I could look at it with the <a href="http://www.baudline.com/">baudline signal analyzer</a>. Thank you Jane and Jon.<br />
<br />
This Voyager signal was recorded at 8419.62 MHz and was packetized into an .archive-compamp file by <a href="http://setiquest.org/wiki/index.php/SonATA">SonATA</a>. The following command line streams the 4-bit <a href="http://baudline.com/manual/glossary.html#quadrature">quadrature</a> Voyager samples into baudline:<br />
<br />
<span style="font-size: x-small;"><span style="font-family: "Courier New",Courier,monospace;">cat 2012-11-07_21-14-05_UTC.act61.dx1011.id-4.L.archive-compamp | extract_compamp_data 9 | baudline -<a href="http://baudline.com/manual/options.html#session">session</a> compamp -<a href="http://baudline.com/manual/options.html#stdin">stdin</a> -format s4 -channels 2 -<a href="http://baudline.com/manual/options.html#quadrature">quadrature</a> -samplerate 711.1111<span style="font-size: x-small;"> </span>-re<span style="font-size: x-small;">cord</span></span></span><br />
<br />
<span style="font-size: small;"><span style="font-size: small;">This Unix command line <span style="font-size: small;">of multiple pipes extracts the </span>9th channel <span style="font-size: small;">from the .archive-compamp<span style="font-size: small;"> file and <span style="font-size: small;">feeds that into baudline's sta<span style="font-size: small;">ndard input with the appropriate con<span style="font-size: small;">figuration settings<span style="font-size: small;">. <span style="font-size: small;">Note the .L. in the <span style="font-size: small;">compamp </span>file name. </span></span></span></span> </span></span></span>I don't know why </span>SonATA <span style="font-size: small;">does this<span style="font-size: small;"> but the</span></span><span style="font-size: small;"> X & Y linear polarizatio<span style="font-size: small;">n .compamp files are <span style="font-size: small;">labeled</span> as being L & R circular polariza<span style="font-size: small;">tion<span style="font-size: small;">.</span></span></span></span></span><br />
<span style="font-size: x-small;"><span style="font-family: "Courier New",Courier,monospace;"><br /></span></span>
<span style="font-size: large;">X polarization</span><br />
<span style="font-size: small;">Be<span style="font-size: small;">low is <span style="font-size: small;">the b<span style="font-size: small;"><span style="font-size: small;">audline <a href="http://baudline.com/manual/display.html#spectrogram">spectrogram</a> of the X linear polarization. Note the weak diagonal signal<span style="font-size: small;"> on the left side that starts on the top at around -160 Hz. <span style="font-size: small;">This <span style="font-size: small;">d<span style="font-size: small;">r<span style="font-size: small;">ifting line is caused by the Earth's rotation and <span style="font-size: small;">the Doppler E<span style="font-size: small;">ffect.<span style="font-size: small;"> I call it Doppler Drift<span style="font-size: small;">. </span>Click on the image below for a larger and better view of this weak signal.</span></span></span></span></span></span></span></span></span></span></span></span></span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1tYHmZZT5BQqj9fVh5rVGPCk_Opya37jTLCOAfTlvwAVrT6_jhcXAw_vBlQ2YMQm0EHumBmNFRzZpXqTI9uM0ZAsOQchxUXmp3sd8IlOHI2jbxk5PL2A3jCS7wZF1lNPLC98S/s1600/Voyager+spectro+L.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1tYHmZZT5BQqj9fVh5rVGPCk_Opya37jTLCOAfTlvwAVrT6_jhcXAw_vBlQ2YMQm0EHumBmNFRzZpXqTI9uM0ZAsOQchxUXmp3sd8IlOHI2jbxk5PL2A3jCS7wZF1lNPLC98S/s320/Voyager+spectro+L.png" height="239" width="320" /></a></div>
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<span style="font-size: large;">Y polarization</span><br />
<span style="font-size: small;">Be<span style="font-size: small;">low is <span style="font-size: small;">the b<span style="font-size: small;"><span style="font-size: small;">audline spectrogram of the <span style="font-size: small;">Y</span> linear polarization file.</span></span></span></span></span> Note that the signal is bit stronger than it was in the X polarization above. Compare this with the signal strength from the <a href="http://baudline.blogspot.com/2011/03/setiquest-voyager.html">July 2010 Voyager data analysis</a>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhoe0Y65RG6tARTD4rwepHMgTCaJKgytIhju5WRYKR6meoZ8DTkCelVxpWfsUdm2r4IbZ-Ljnb6RAwerMyyYq836Csk3bETLmezdL6ecHgh2dTu6ehRcrEBN0dPKrMz7pc1aeEn/s1600/Voyager+spectro+R.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhoe0Y65RG6tARTD4rwepHMgTCaJKgytIhju5WRYKR6meoZ8DTkCelVxpWfsUdm2r4IbZ-Ljnb6RAwerMyyYq836Csk3bETLmezdL6ecHgh2dTu6ehRcrEBN0dPKrMz7pc1aeEn/s320/Voyager+spectro+R.png" height="239" width="320" /></a></div>
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<span style="font-size: large;">X & Y polarizations</span><br />
The two spectrograms above were combined to create this dual channel spectrogram (see the <a href="http://baudline.com/manual/channel_mapping.html#channel_mapping">Channel Mapping</a> window). The X polarization is green and the Y polarization is purple. Notice how this dual channel technique makes the weak drifting Voyager signal easier to see. It also makes it easy to visually compare both polarizations.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiN4L-qMfd4aCBO_NhjsAiKI0-OHBt4Bg1xJpTK-NprDnxObyD7KuGMQU3gtUyQrV91itlVQfNBlpfc481bRkz9efXiNVe3Oj8qKzk7uQPwgz4GkCRlwZzbvr-DgE4-OSqGDSgf/s1600/Voyager+spectro+LR.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiN4L-qMfd4aCBO_NhjsAiKI0-OHBt4Bg1xJpTK-NprDnxObyD7KuGMQU3gtUyQrV91itlVQfNBlpfc481bRkz9efXiNVe3Oj8qKzk7uQPwgz4GkCRlwZzbvr-DgE4-OSqGDSgf/s320/Voyager+spectro+LR.png" height="239" width="320" /></a></div>
<br />
If you click to look closely at the larger version of this image you'll see several very weak crisscrossing lines and curved <a href="http://baudline.blogspot.com/2006/05/vlf-whistler-echo-train.html">whistler</a>-like shapes that are much weaker than the main drifting signal. These very weak features could be real or they could be just random shapes in the noise floor. Need more data to know for sure. If they are real then they're likely artifacts caused by distortion somewhere in the signal path.<br />
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<br />
<span style="font-size: large;">Auto Drift</span><br />
Baudline's <a href="http://baudline.com/manual/process.html#auto_drift">Auto Drift</a> feature was enabled and each of the X & Y polarizations were pasted into the <a href="http://baudline.com/manual/average.html#average">Average</a> window. The Y polarization (purple) is about half a dB stronger which confirms our spectrogram strength observation mentioned above. The drifting signals are about 3 - 4 sigma above the noise floor. The <a href="http://baudline.com/manual/measurements.html#auto_drift_rate">auto drift rate</a> measurement window reports that the signal is drifting by -0.5770 Hz/second.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbEbZ27qavpsoj0ZJgMQPdjVm7JBPwH6ueh6nIrthm58C191CxchwOjB7QCcesAU2ipKjbYT_l2haXGrpiPgVSykgV6h6AKENo_FQzZTWLy3eVucqAg8cbvi0gh5-uq8uFX7PJ/s1600/Voyager+average+LR.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbEbZ27qavpsoj0ZJgMQPdjVm7JBPwH6ueh6nIrthm58C191CxchwOjB7QCcesAU2ipKjbYT_l2haXGrpiPgVSykgV6h6AKENo_FQzZTWLy3eVucqAg8cbvi0gh5-uq8uFX7PJ/s320/Voyager+average+LR.png" height="126" width="320" /></a></div>
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Next Auto Drift is enabled with baudline's spectrogram display. Think of this as a 4-dimensional version of the above Average display where the additional dimensions are time and vector space. Each pixel has 20865 possible vector paths and that works out to about 10 billion possible vector paths seen in the spectrogram image below. <span style="font-size: small;">Good thing that Auto Drift is a quick O(n log n) algorithm<span style="font-size: small;"> <span style="font-size: small;">so that image rendering is rather fast. </span></span></span> For reference the <a href="http://baudline.com/manual/process.html#drift_integrator">Drift Integrator</a>'s settings were: beam width = 326 slices (16 seconds), optimum overlap = 400%, Auto Drift quality = 8.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhagkM5p92iN6gcHSsCsy6OnfPewhiiIbbFS0VqFcA6YL7iZbjxfm8l3vZSXpxXkhRpDtBrAmh3gc4A6jeQydS7yaW9aHPFcuqNq_oXGpMx4Ez6u5gdEVNIw5axgEKDkO_wRa0A/s1600/Voyager+auto+s=326+q=8.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhagkM5p92iN6gcHSsCsy6OnfPewhiiIbbFS0VqFcA6YL7iZbjxfm8l3vZSXpxXkhRpDtBrAmh3gc4A6jeQydS7yaW9aHPFcuqNq_oXGpMx4Ez6u5gdEVNIw5axgEKDkO_wRa0A/s1600/Voyager+auto+s=326+q=8.png" height="224" width="320" /></a></div>
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Notice how the weak drifting signal stands out and is easier to see. Also note how the drifting signal fades in strength between the X (green) & Y (purple) polarizations. This image reminds me a lot of ice crystals on a window pane. It isn't that far out there since the Auto Drift algorithm that generates the spectrogram vectors is somewhat similar to how ice crystals grow. <br />
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<span style="font-size: large;">Histogram</span><br />
The <a href="http://baudline.com/manual/histogram.html#histogram">Histogram</a> window shows 5 vertical lines (bins) that make a Gaussian-like shape (see <a href="http://baudline.com/manual/glossary.html#AWGN">AWGN</a>). This sparse histogram is not surprising since the input signal has 4-bit quantization. Note that only slightly more than two bits are being utilized.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMT8EhXn5mzycIylNL3-YShzzGxhm-14e_o1C8R3Fj6RBp3HuOIWEsWVZwgb89UYkkihACXeduXb8sfAnc7Rul6c-D55vfh6CyTUQNyLBW6sX_Xr6fJwBnf1C6t-jMqDBGYy5d/s1600/Voyager+histogram.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMT8EhXn5mzycIylNL3-YShzzGxhm-14e_o1C8R3Fj6RBp3HuOIWEsWVZwgb89UYkkihACXeduXb8sfAnc7Rul6c-D55vfh6CyTUQNyLBW6sX_Xr6fJwBnf1C6t-jMqDBGYy5d/s320/Voyager+histogram.png" height="161" width="320" /></a></div>
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<span style="font-size: large;">Waveform</span><br />
Baudline's <a href="http://baudline.com/manual/waveform.html#waveform">Waveform</a> window shows a time series view of what the 4-bit quadrature signal looks like. This sample distribution matches what is seen in the Histogram window above. Do you see the signal? It's the magic of <a href="http://baudline.com/manual/glossary.html#DSP">DSP</a> that allows such a weak drifting signal to be encoded in so few bits.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQTROOB3zEL9tRKle9Sw2fIVPpvk5WjNNTqxoU1xKWmvaVrwt_oaDPan6qQfKehQQ3zChg1R5-0EeQWmQCnX_Nol6ZND8vsiDfNH_upP_InrLON-57K2-_o0fnahY3ZcZ8jPLi/s1600/Voyager.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><br /></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGJB0dsehFxf6K8MdW91nANboByw7vu6NHq5nBLfY5U_a5JdAyJLloU2LsKadkLPymtpBCBDiGv3L4Ie7oP0tLg8VFUEn5J79InDSsjsI2F-xSO56jdSGkwaMfIyohBQ7OrbsF/s1600/Voyager+waveform.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGJB0dsehFxf6K8MdW91nANboByw7vu6NHq5nBLfY5U_a5JdAyJLloU2LsKadkLPymtpBCBDiGv3L4Ie7oP0tLg8VFUEn5J79InDSsjsI2F-xSO56jdSGkwaMfIyohBQ7OrbsF/s320/Voyager+waveform.png" height="77" width="320" /></a></div>
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<span style="font-size: large;">Conclusion</span><br />
No modulation characteristics are visible in either the baudline spectrogram or Average window views. The Voyager signal looks like a non-information baring pilot tone. This could be due to the weak nature of the signal or because Voyager was not transmitting at the time the signal was recorded.<br />
<br />
As mentioned above<span style="font-size: small;">,</span> this <b>setiQuest Voyager 1 redux</b> capture is much weaker than the <a href="http://baudline.blogspot.com/2011/03/setiquest-voyager.html">July 2010 Voyager 1 signal I previously blogged about</a>. A good question is why is it weaker? Here is a list of possible explanations:<br />
<ul>
<li>28 months have passed and Voyager is now 8.3 AU farther away.</li>
<li>Voyager has entered the Heliosheath and the compressed turbulent solar wind is increasing signal attenuation. </li>
<li>Voyager's Plutonium-238 power plant has a half-life of 88 years and is producing less power for signal transmission.</li>
<li>Voyager's dish antenna could be slightly off axis and is not pointed directly at Earth.</li>
<li>The ATA dishes could be slightly off axis and are not pointed directly at Voyager.</li>
<li>Reduced collection area due to some ATA dishes being off-line.</li>
<li>Some cryo feed units require maintenance and are resulting in a higher ATA system temperature. </li>
<li>An error in the calculation of the ATA beamformer coefficients.</li>
<li>Increased local RFI mixed with Walshing artifacts are effectively reducing ATA system gain. </li>
<li>Rainy cloudy weather in Hat Creek, California.</li>
<li>The compamp 4-bit sample quantization is pushing up the noise floor. The first Voyager data collection used 16-bit samples.</li>
<li>Aliens have found the Voyager space probe and are fiddling with its innards.</li>
</ul>
Some of these explanations are unlikely or not significant enough to account for the reduction in signal strength. What do you think? Please discuss in the comments section.<br />
<br />
<br />
<span style="font-size: large;">Links </span><br />
<ul>
<li><a href="http://setiquest.org/forum/topic/baudline-analysis-voyager-1-redux">http://setiquest.org/forum/topic/baudline-analysis-voyager-1-redux</a></li>
<li><a href="http://baudline.blogspot.com/2011/03/setiquest-voyager.html">http://baudline.blogspot.com/2011/03/setiquest-voyager.html </a></li>
<li><a href="http://voyager.jpl.nasa.gov/">http://voyager.jpl.nasa.gov/ </a></li>
<li><a href="http://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html">http://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html</a></li>
<li><a href="http://twitter.com/NASAVoyager">http://twitter.com/NASAVoyager</a></li>
<li><a href="http://twitter.com/NASAVoyager2">http://twitter.com/NASAVoyager2</a> </li>
</ul>
<span style="font-size: x-small;">Data licensed through <a href="http://www.seti.org/">SETI</a>.</span><br />
<span style="font-size: x-small;">Software licensed through <a href="http://www.sigblips.com/">SigBlips</a>.</span><br />
<br />baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com8tag:blogger.com,1999:blog-19780926.post-86732458538714682182011-03-11T15:55:00.000-08:002013-05-07T17:11:48.729-07:00setiQuest VoyagerThe <a href="http://www.baudline.com/">baudline signal analyzer</a> looked at the setiQuest Voyager data set that is part of the <a href="http://setiquest.org/wiki/index.php/SonATA">SonATA</a> source code package. The NASA Voyager 1 probe is about 106 AU from the Sun which makes it the most distant object humans have ever sent into space. Voyager is very far away and it's telemetry signal is very weak.<br />
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This Voyager data set was collected from the multicast UDP packets output by one of SonATA's channelizers. The format is different from previous baudline/setiQuest analyses. It is 16-bit <a href="http://baudline.com/manual/options.html#quadrature">quadrature</a> samples but more importantly it is packetized and contains two polarizations. A simple strip_header demux program was created for this analysis.<br />
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<div>
The following command line was used to stream the Voyager data file into baudline:</div>
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<span style="font-size: 85%;"><span style="font-family: courier new;">cat vger-2010-07-14-406.pktdata | strip_header | baudline -session voyager -stdin -format le16 -channels 2 -quadrature -samplerate 546133</span></span><br />
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<span style="font-size: 180%;">8419.53 MHz</span><br />
The Voyager signal is so weak that the spectrogram looks like noise. Accumulating spectral curves with the <a href="http://baudline.com/manual/average.html#average">Average display</a> (green Fourier below) to reduce the variance of the noise floor doesn't help. Enabling baudline's <a href="http://baudline.com/manual/process.html#auto_drift">Auto Drift</a> algorithm (purple below) changes the situation and the drifting signal pops out of the noise.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmNzyYn4EHW-vZV20p4w_PAeAa1nELRKwCQYFXW0NsJIPMhKFzNW6D5L-rG3Tt5z88c76LO9hNJF28jKiYWJVWD3HAZNS0Er9o4cPPSqh2Mv-fGIvpJlcRJ9rr4KOCKwh3U0ey/s1600/voyager+average.png"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmNzyYn4EHW-vZV20p4w_PAeAa1nELRKwCQYFXW0NsJIPMhKFzNW6D5L-rG3Tt5z88c76LO9hNJF28jKiYWJVWD3HAZNS0Er9o4cPPSqh2Mv-fGIvpJlcRJ9rr4KOCKwh3U0ey/s400/voyager+average.png" id="BLOGGER_PHOTO_ID_5582971536682767074" style="cursor: pointer; display: block; height: 133px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The standard Fourier transform found a flat featureless spectrum. Auto Drift found a strong signal near +11200 Hz about 10 sigma above the noise floor that has a -0.473 Hz/sec drift rate. Let us zoom in and inspect this signal is greater detail.<br />
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<span style="font-size: 180%;">+11689 Hz</span><br />
<a href="http://baudline.com/manual/input.html#decimate_by">Decimation</a> by 2048 and a 2048 point FFT for a 0.26 Hz/bin resolution gives a better view. Here is baudline's spectrogram display:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdTnlw3piUBIb48pjJL1GYlXKFQgU3awYV8A4dkcMjXZjQ_5L-ZN0eHOAvK17aWrl5zvCVooeL8eYXeR3y203Z3IOCUkrP_2jwCfUuw0C2Pg8XAd9dfBtYwUpLP23Eti-0yS9M/s1600/voyager+spectro+266.667.png"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdTnlw3piUBIb48pjJL1GYlXKFQgU3awYV8A4dkcMjXZjQ_5L-ZN0eHOAvK17aWrl5zvCVooeL8eYXeR3y203Z3IOCUkrP_2jwCfUuw0C2Pg8XAd9dfBtYwUpLP23Eti-0yS9M/s400/voyager+spectro+266.667.png" id="BLOGGER_PHOTO_ID_5583300295024638658" style="cursor: pointer; display: block; height: 377px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The Voyager telemetry signal is Doppler drifting at a very linear -65.4 Hz / 139 seconds = -0.471 Hz/second rate due to the Earth's rotation. This manual drift rate measurement matches the <a href="http://baudline.com/manual/measurements.html#auto_drift_rate">Auto Drift rate</a> value to within an error ±0.002 Hz/sec.<br />
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<span style="font-size: 180%;">Conclusion</span><br />
Baudline's Auto Drift feature made finding the drifting Voyager signal extremely easy. After it was found in the Average display the spectrogram display was zoomed and scrolled into position. A -0.47 Hz/sec drift rate seems a bit high. Need to check with the SETI Institute if this is a reasonable value. Next step demodulation ...<br />
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<span style="font-size: 180%;">Links</span><br />
<ul>
<li><a href="http://setiquest.org/forum/topic/baudline-analysis-voyager">http://setiquest.org/forum/topic/baudline-analysis-voyager</a></li>
<li><a href="http://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html">http://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html</a></li>
<li><a href="http://twitter.com/NASAVoyager2">http://twitter.com/NASAVoyager2</a></li>
</ul>
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<span style="font-size: 85%;">Data licensed through <a href="http://www.seti.org/">SETI</a>.<br />Software licensed through <a href="http://www.sigblips.com/">SigBlips</a>.</span>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com3tag:blogger.com,1999:blog-19780926.post-52639562631281089332010-11-09T16:39:00.000-08:002010-11-10T13:04:05.295-08:00Carl Sagan's birthday piThe <a href="http://kepler.nasa.gov/">NASA Kepler mission</a> and the <a href="http://www.seti.org/">SETI Institute</a> are celebrating Carl Sagan's birthday with an <a href="http://kepler.nasa.gov/education/sagan/">essay contest</a>. I thought that I'd do something different and honor Carl Sagan by analyzing the digits of pi with the <a href="http://www.baudline.com/">baudline signal analyzer</a>. In Carl Sagan's novel "Contact" finding a signal hidden in the digits of pi was a theme element that was removed from the movie version. Since I've been spending a lot of my free time <a href="http://baudline.blogspot.com/search/label/SETI">analyzing setiQuest data sets</a> it seems rational to apply some of those same techniques to the irrational number pi.<br /><br />So my plan is to use baudline and conduct Fourier analysis on the digits of pi in binary (base-2). Here is a description of the procedure:<br /><ol><li>Compute millions of decimal digits of pi.</li><li>Convert the decimal digits of pi to binary (base-2).<br /></li><li>Analyze the binary digits with the baudline signal analyzer.</li></ol><br />Existing software available on the Internet was used to calculate about 50 million decimal digits of pi. I wrote a simple O(n^2) base conversion routine that did multiple-digit base multiply and carry using integer division and modulo. For base-2 conversion accuracy verification I used the amazing Bailey–Borwein–Plouffe (BBP) formula algorithm to spot check several hexadecimal digits. The data was then feed into baudline using the <a href="http://baudline.com/manual/options.html#stdin">standard input</a> (stdin) or the <a href="http://baudline.com/manual/open_file.html#raw_parameters">raw parameter </a>interface.<br /><br /><br /><span style="font-size:180%;">white uniform noise</span><br />The digits of pi are believed to be normal in that their distribution is random. Before looking at pi let us first take a look at the spectral characteristics of white uniform noise. Baudline settings:<br /><ol><li><a href="http://baudline.com/manual/tone_generator.html#tone_generator">Tone Generator</a> set to output <span style="font-weight: bold;">white uniform noise</span>.</li><li><a href="http://baudline.com/manual/input.html#input_devices">Input Devices</a> tone generator <span style="font-weight: bold;">loopback</span> enabled.</li><li>Input <a href="http://baudline.com/manual/channel_mapping.html#channel_mapping">Channel Mapping</a> operation set to <span style="font-weight: bold;">clip</span>.</li></ol>Here is a spectrogram of about one million samples of clipped uniform white noise:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcBKZSNTJgf23OuKQtfdwKl9KYsyqq79yxX1M6K12LUafjH4TX_4tA0Bs6I9TCh14XNONeg2Meyix_jrZVpSO3ax1gxBpkM6OuyCAtxvpsFRDNm5KbYtmhZvVqcMxzcCL4D2E0/s1600/uniform+white+noise+spectrogram.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 377px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcBKZSNTJgf23OuKQtfdwKl9KYsyqq79yxX1M6K12LUafjH4TX_4tA0Bs6I9TCh14XNONeg2Meyix_jrZVpSO3ax1gxBpkM6OuyCAtxvpsFRDNm5KbYtmhZvVqcMxzcCL4D2E0/s400/uniform+white+noise+spectrogram.png" alt="" id="BLOGGER_PHOTO_ID_5537723389607367394" border="0" /></a><br />Here is an Average spectrum of 67 Msamples:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9GREA_60gbqKojISz_gNqCOFsQ1zVpFJgA1abKLYmun8JnE4Pp9UaKIyKsD12Jbnbc66cY85mtqOvqYJaHWY483eJ-Z2vxcgTFKhJSbe4qy2WWfbEURfobDBH36kRNBNI-Fwe/s1600/uniform+white+noise+average.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 165px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9GREA_60gbqKojISz_gNqCOFsQ1zVpFJgA1abKLYmun8JnE4Pp9UaKIyKsD12Jbnbc66cY85mtqOvqYJaHWY483eJ-Z2vxcgTFKhJSbe4qy2WWfbEURfobDBH36kRNBNI-Fwe/s400/uniform+white+noise+average.png" alt="" id="BLOGGER_PHOTO_ID_5537732525861432562" border="0" /></a><br /><br /><span style="font-size:180%;">pi binary (base-2)<br /></span>The decimal (base-10) digits of pi were converted to binary (base-2). Here is a picture of the binary waveform:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8X3I0NefOQUXE8zXO06_ABivJBAL7S9rmNoNLgIWhgcwjQUpTOxuXQqgXiN8xZZcYlfvUOhYQjhUFqBQ4ol2opd065bUDCIDTpfAAGQccG9G97z0KBWHvQfp5BzTG-HvSW3vR/s1600/pi+binary+waveform.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 112px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8X3I0NefOQUXE8zXO06_ABivJBAL7S9rmNoNLgIWhgcwjQUpTOxuXQqgXiN8xZZcYlfvUOhYQjhUFqBQ4ol2opd065bUDCIDTpfAAGQccG9G97z0KBWHvQfp5BzTG-HvSW3vR/s400/pi+binary+waveform.png" alt="" id="BLOGGER_PHOTO_ID_5538029270539325682" border="0" /></a><br />Here is a spectrogram of about one million samples of binary (base-2) pi:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRMMvHk8IGgrxID6twtkhCxFgkPU5WMmLEm7Z5VjeXOZowj_gJBvqzhkemKW65cHszNTk8mZuNw-aSqSgqf5nNVfqN0Uxio92c9bLHqARG55kXNbuD0g81n_vvh9Al_F4nGazZ/s1600/pi+binary+spectrogram.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 377px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRMMvHk8IGgrxID6twtkhCxFgkPU5WMmLEm7Z5VjeXOZowj_gJBvqzhkemKW65cHszNTk8mZuNw-aSqSgqf5nNVfqN0Uxio92c9bLHqARG55kXNbuD0g81n_vvh9Al_F4nGazZ/s400/pi+binary+spectrogram.png" alt="" id="BLOGGER_PHOTO_ID_5537723620376826370" border="0" /></a><br />Here is an Average spectrum of 67 Msamples:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPuVwU3g-lgHL03HXiGufMVmtTw62Jf8D3rYA9Zt-Od4i1v_6O3eal96wRL8oUt2seNopmMnoT9yNfspzM_Buziw875nP5wUfCMXFCcG9eFNB2Iobx04sSghWJzSmS0GcTGg2F/s1600/pi+binary+average.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 165px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPuVwU3g-lgHL03HXiGufMVmtTw62Jf8D3rYA9Zt-Od4i1v_6O3eal96wRL8oUt2seNopmMnoT9yNfspzM_Buziw875nP5wUfCMXFCcG9eFNB2Iobx04sSghWJzSmS0GcTGg2F/s400/pi+binary+average.png" alt="" id="BLOGGER_PHOTO_ID_5537732763476394418" border="0" /></a><br /><br /><span style="font-size:180%;">Comparison</span><br />Let us compare the above uniform white noise and binary pi spectral displays. Click on the two spectrograms above for full size versions and see if you can find any significant differences. They look very similar to me. The two Average spectrums are fairly flat with equal energy and variance. Nothing stands out as odd, unusual, or different. So the conclusion from the perspective of these basic frequency domain tests is that white uniform noise is indistinguishable from the binary digits of pi.<br /><br />If there is some hidden structure in pi then more sophisticated DSP techniques will need to be developed and utilized. Stay tuned ...baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-56609561819783604042010-11-06T15:27:00.000-07:002012-09-19T12:11:10.453-07:00setiQuest Lagrange-4The <a href="http://www.baudline.com/">baudline signal analyzer</a> looked at the setiQuest Lagrange-4 data sets from 1420, 2008, and 3991 MHz. The Lagrangian points are locations in space that are in gravitational equilibrium. The L4 and L5 points are stable orbits which would make them an ideal place to store an "object" for a very long time. Another thought is that objects may tend to naturally collect at the L4 and L5 points. The Sun-Earth L4 point was the target of this setiQuest observation. <br />
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The following command line was used to stream the Lagrange-4 data files into a prototype version of baudline:</div>
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<div style="font-family: courier new;">
<span class="Apple-style-span" style="font-size: 85%;"><span class="Apple-style-span">cat 2010-10-08-Lagrange-4_3991_3-8bit-* | ./baudline -<a href="http://baudline.com/manual/options.html#session">session</a> proto -<a href="http://baudline.com/manual/options.html#stdin">stdin</a> -format s8 -channels 2 -<a href="http://baudline.com/manual/options.html#quadrature">quadrature </a>-samplerate 8738133 -pause -<a href="http://baudline.com/manual/options.html#utc">utc</a> 0</span></span></div>
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<span class="Apple-style-span" style="font-size: x-large;">1420 MHz</span></div>
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The frequency of interstellar Hydrogen. Here is the <a href="http://baudline.com/manual/average.html#average">Average</a> spectral display:</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitBVtSkRwOAGXpvn7yEwHholmkHtpnyH9T7ytPPliqELNr-r1B0KGClsmz9Zqf_Gku5U6rLSC5miv2ZjSL-92L1in_vH_nfTb8rA4xBsl_MNl74uNuTIK4qOIPn1fwR_rXDs6a/s1600/1420+average.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545841335755354786" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitBVtSkRwOAGXpvn7yEwHholmkHtpnyH9T7ytPPliqELNr-r1B0KGClsmz9Zqf_Gku5U6rLSC5miv2ZjSL-92L1in_vH_nfTb8rA4xBsl_MNl74uNuTIK4qOIPn1fwR_rXDs6a/s400/1420+average.png" style="cursor: pointer; display: block; height: 169px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Here is the signal at 1420 - 2.682582 = 1417.317418 MHz <a href="http://baudline.com/manual/glossary.html#decimation">decimated</a> by 4096. Note Hz=2X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3ne7_VwqEFB0Gw7UyauOu-SN4NCwTRTvVwCQTxyMIIwj0u8NRBqsDMgb_gTM8X6I5kybdwspm4g3h_LDYCc2L5cB7H7eoz92lc4X0Kcv_VpJDIuHR9RM07ibtjZQa1fCtdT7H/s1600/1420+-2682582+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545851770750457138" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3ne7_VwqEFB0Gw7UyauOu-SN4NCwTRTvVwCQTxyMIIwj0u8NRBqsDMgb_gTM8X6I5kybdwspm4g3h_LDYCc2L5cB7H7eoz92lc4X0Kcv_VpJDIuHR9RM07ibtjZQa1fCtdT7H/s400/1420+-2682582+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This unusual signal jumps around making a drift measurement difficult. Four noise blobs of 33 Hz width that have some horizontal spectrum structure are present. The two middle blobs are about 100 seconds in duration and they appear to have different center frequencies.<br />
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Listen to this modulated signal in the following video. Select 720p HD and fullscreen for the best resolution.<br />
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<center>
<object height="336" width="420"><param name="movie" value="http://www.youtube.com/v/eS45HfGdWqQ?fs=1&hl=en_US&rel=0&hd=1&color1=0x234900&color2=0x4e9e00"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/eS45HfGdWqQ?fs=1&hl=en_US&rel=0&hd=1&color1=0x234900&color2=0x4e9e00" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="336" width="420"></embed></object></center>
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Here is the signal at 1420 - 2.045546 = 1417.954454 MHz decimated by 4096. Note Hz=2X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMrJIr2l7KQLYa_AXSwV1UbVum78kpiOnyEa7WWYMhnlzVK5IGxbvCJwEFQ8WAXnyb3SES0oIEYKoMnSNZ9OF5MRvjfePdk5tTS1l21YNxYnC9Drc_FEkVuEoAXHcr7qBJTiNc/s1600/1420+-2045546+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5546223782532414354" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMrJIr2l7KQLYa_AXSwV1UbVum78kpiOnyEa7WWYMhnlzVK5IGxbvCJwEFQ8WAXnyb3SES0oIEYKoMnSNZ9OF5MRvjfePdk5tTS1l21YNxYnC9Drc_FEkVuEoAXHcr7qBJTiNc/s400/1420+-2045546+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This unusual wandering signal looks a lot like a 4X zoomed out version of the signal seen above at -2682582 Hz. The signal has a width of 8 Hz and drifts +19 Hz from the start to the end but it's motion looks more oscillatory.<br />
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Listen to this modulated signal in the following video. Select 720p HD and fullscreen for the best resolution.<br />
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<center>
<object height="336" width="420"><param name="movie" value="http://www.youtube.com/v/foTot7wsRe8?fs=1&hl=en_US&rel=0&hd=1&color1=0x234900&color2=0x4e9e00"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/foTot7wsRe8?fs=1&hl=en_US&rel=0&hd=1&color1=0x234900&color2=0x4e9e00" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="336" width="420"></embed></object></center>
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Here is the chunk of bandwidth from 1420.029867 to 1420.032000 MHz.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLbkeOmMhqJ0iCljB1J8l78tnRctlnv13rql3mgcqKj5Rw43IgPtYVe_BqhNsK095kta7OeTF2Motjt8niwMppmQSyCdO8Xbcdh32cQCbpTTSxfjeCZ77e6UcLrsqQ5GQW4C8n/s1600/1420+%252B29867...%252B32000+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5546234232270581026" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLbkeOmMhqJ0iCljB1J8l78tnRctlnv13rql3mgcqKj5Rw43IgPtYVe_BqhNsK095kta7OeTF2Motjt8niwMppmQSyCdO8Xbcdh32cQCbpTTSxfjeCZ77e6UcLrsqQ5GQW4C8n/s400/1420+%252B29867...%252B32000+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>Three drifting signals are visible and each will be investigated below. Note that these three signals are about -460 kHz left of Hydrogen which has been a popular location for <a href="http://baudline.blogspot.com/search/label/SETI">previous setiQuest</a> signals of interest.<br />
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Here is the first signal at 1420 + 0.030525 = 1420.030525 MHz decimated by 4096. Note Hz=4X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzEgwJPs0u8QYBiqdZQXbIQoe__l1ytukMld15ulU3Cv6xYEjSNgbQMYpmFY-fee5G3WEUZlgIXPc3ZfJokVDaTy5ifZESHAWr0dVNKSlRKu_A6cOho1mtZJycCd9B6kpEuf3z/s1600/1420+%252B30525+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5546240464053900690" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzEgwJPs0u8QYBiqdZQXbIQoe__l1ytukMld15ulU3Cv6xYEjSNgbQMYpmFY-fee5G3WEUZlgIXPc3ZfJokVDaTy5ifZESHAWr0dVNKSlRKu_A6cOho1mtZJycCd9B6kpEuf3z/s400/1420+%252B30525+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
A drifting random walk with a +107 Hz / 603 seconds = +0.177 Hz/sec drift rate. The lower half has an oscillatory drift shape with an 87 second period.<br />
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Here is the second signal at 1420 + 0.031453 = 1420.031453 MHz decimated by 4096. Note Hz=8X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjD4Ay4AmyF3BJrJ6blclXKr-Ox1e_DCvqgrs2mvuf5d6Uh74d_TlsyuUMUcWKi47Gw7wm84AcyDyQMoYCwH2TZNKctvxjdL8MgJBBdUT6vPHhsRA6UL4eTzOdLLBu4YlrcLBQZ/s1600/1420+%252B31453+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5546244327213535586" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjD4Ay4AmyF3BJrJ6blclXKr-Ox1e_DCvqgrs2mvuf5d6Uh74d_TlsyuUMUcWKi47Gw7wm84AcyDyQMoYCwH2TZNKctvxjdL8MgJBBdUT6vPHhsRA6UL4eTzOdLLBu4YlrcLBQZ/s400/1420+%252B31453+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This faint drifting random walk has a drift rate of +342 Hz / 603 seconds = +0.567 Hz/sec.<br />
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Here is the third signal that is at 1420 + 0.031681 = 1420.031681 MHz decimated by 4096.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfwSB5wxz9ruQv0RadTfUzycn_pqi1qC8jkKLxMkP6QaOjjoUhpwSUXKsbvj8QiK8klk2rRt-OohSzxOjp6zxzcRcsj_6otQh9csNDasNzmxQi5M3_trrsnl5WNPm2BX2Rtnw4/s1600/1420+%252B31681+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545869960958416482" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfwSB5wxz9ruQv0RadTfUzycn_pqi1qC8jkKLxMkP6QaOjjoUhpwSUXKsbvj8QiK8klk2rRt-OohSzxOjp6zxzcRcsj_6otQh9csNDasNzmxQi5M3_trrsnl5WNPm2BX2Rtnw4/s400/1420+%252B31681+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
This wandering random walk is drifting at a net +17.1 Hz / 603 seconds = +0.0284 Hz/sec rate. Closer inspection by zooming into the time axis shows distinct frequencies that move by deltas of ±0.8 Hz. Using baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bar tool</a> an extremely repetitive 3.753 symbol/second rate was measured. This looks very similar to the <a href="http://baudline.com/manual/glossary.html#FSK">FSK</a>-like zigzag modulation that was seen in the <a href="http://baudline.blogspot.com/2010/09/setiquest-kepler-4b-redux.html">Kepler-4b redux</a> analysis. That modulated signal was -483 kHz to the left of Hydrogen's corrected center of mass. This signal is about -460 kHz to the left of Hydrogen.<br />
<br />
Listen to the 1420.031681 MHz modulated signal in the following video. Select 720p HD and fullscreen for the best resolution.<br />
<br />
<center>
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<br />
<br />
Here is the signal at 1420 + 0.036009 = 1420.036009 MHz decimated by 512.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbosGIR2VjyXAlC1HaSjV9inrSD0VsUskbc02-vOSl_fsGmgJMfc9wS1gyBf7pu7Q8mXimNw_vJbhAI-uwDVaOlNjnHG5-cj3R1cLF4CE2zipAZ6YG2yKOR9c1-iPOlTTP5IRI/s1600/1420+%252B36009+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5547695855149958050" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbosGIR2VjyXAlC1HaSjV9inrSD0VsUskbc02-vOSl_fsGmgJMfc9wS1gyBf7pu7Q8mXimNw_vJbhAI-uwDVaOlNjnHG5-cj3R1cLF4CE2zipAZ6YG2yKOR9c1-iPOlTTP5IRI/s400/1420+%252B36009+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This fairly constant non-stationary signal is drifting at +169 Hz / 603 seconds = +0.280 Hz/sec. This interesting thing about this about this signal is its slight wiggles and small discontinuous jumps in frequency. Since the decimation rate was only 512 these fluctuations are actually much greater when compared to the other spectrograms in this blog post.<br />
<br />
Here is the chunk of bandwidth from 1420.029867 to 1420.032000 MHz.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjo81rUF6IUtToeihKs2JdktGNBCt9-QF9KOsuKS_2pxak0i3VVqEyxwLvPaa30G73iF9pBEqHMbShXmBdVr7yGyi-WjCa-tt1VmyJhyphenhyphentLHiT1WnoyxLxRK1oDvxS2SkM83Ekc3/s1600/1420+%252B38933+...+%252B41067+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5547703564671819090" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjo81rUF6IUtToeihKs2JdktGNBCt9-QF9KOsuKS_2pxak0i3VVqEyxwLvPaa30G73iF9pBEqHMbShXmBdVr7yGyi-WjCa-tt1VmyJhyphenhyphentLHiT1WnoyxLxRK1oDvxS2SkM83Ekc3/s400/1420+%252B38933+...+%252B41067+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Again, three drifting signals are visible. We will zoom in to each signal to investigate further and measure its unique characteristics.<br />
<br />
Here is the first signal at 1420 + 0.039448 = 1420.039448 MHz decimated by 4096. Note Hz=2X.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIbTZr6-UZeKM3QjLTmRcyJ50Vi4vaB4NgMvXn-teDITTC-zrnviTQj9Q5rBEPvmjr5yq36T0XkUjE9OGUkHJYaXZjvHnIWwkOm85SVXGgHJgaw5nnP-kziNbL-4y9RRUq_dbo/s1600/1420+%252B39448+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5547705718796110498" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIbTZr6-UZeKM3QjLTmRcyJ50Vi4vaB4NgMvXn-teDITTC-zrnviTQj9Q5rBEPvmjr5yq36T0XkUjE9OGUkHJYaXZjvHnIWwkOm85SVXGgHJgaw5nnP-kziNbL-4y9RRUq_dbo/s400/1420+%252B39448+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>Strange oscillating drift shape with a +56.0 Hz / 603 seconds = +0.0929 Hz/sec drift rate.<br />
<br />
Here is the second signal at 1420 + 0.040146= 1420.040146 MHz decimated by 4096. Note Hz=4X.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7ZQKFKR6m0cmfYEzeiZbFQvpVuGrrqPcApnOJ6-oMGfEoTLEs09NukaRXjue4irZLUItOsBZxJcxW_9-faNGJPh_h6MOtMAIkTQMXDWM7Fc8H_xo6WB3zzAazGYprescvA_ma/s1600/1420+%252B40146+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5547708195347654226" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7ZQKFKR6m0cmfYEzeiZbFQvpVuGrrqPcApnOJ6-oMGfEoTLEs09NukaRXjue4irZLUItOsBZxJcxW_9-faNGJPh_h6MOtMAIkTQMXDWM7Fc8H_xo6WB3zzAazGYprescvA_ma/s400/1420+%252B40146+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
A drifting random walk whose drift has oscillatory as well as random elements. The net drift rate is +75.5 Hz / 603 seconds = +0.125 Hz/sec.<br />
<br />
Here is the third signal at 1420 + 0.040632 = 1420.040632 MHz decimated by 4096. Note Hz=2X.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhybRi7Uea8CWpoNoWk3-35d8VkiCM810UUV5XIIYm8oV0Hrc1KH6VU6mZQtlXiBHxi98O4PE7GjMsBPA9MDzWy4QCzFi3sC8EVEpqXj619ITj6_qjtEI55FSl8buJu_2cwchIs/s1600/1420+%252B40632+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5547711932660201986" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhybRi7Uea8CWpoNoWk3-35d8VkiCM810UUV5XIIYm8oV0Hrc1KH6VU6mZQtlXiBHxi98O4PE7GjMsBPA9MDzWy4QCzFi3sC8EVEpqXj619ITj6_qjtEI55FSl8buJu_2cwchIs/s400/1420+%252B40632+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
An exact measurement is difficult but this weaker drifting random walk is moving at roughly -20.3 Hz / 462 seconds = -0.0439 Hz/sec.<br />
<br />
Here is a signal at 1420 + 0.045422 = 1420.045422 MHz decimated by 4096.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNYJzetzAFOp8B1Ov8Vxf5vBldLqVFM7on-crvbVok7GACo8dG02zD-3g6rRgFb3zMBuGfc-T3zSi6Pabwx-nRK7WziM01b7b_bEvoJsF9NmVeGmh-0LAfESsuv9cOZuHtsv-n/s1600/1420+%252B45422+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5547714429303320322" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNYJzetzAFOp8B1Ov8Vxf5vBldLqVFM7on-crvbVok7GACo8dG02zD-3g6rRgFb3zMBuGfc-T3zSi6Pabwx-nRK7WziM01b7b_bEvoJsF9NmVeGmh-0LAfESsuv9cOZuHtsv-n/s400/1420+%252B45422+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
This narrow band noise signal is almost stationary with a -2 Hz / 603 seconds = -0.003 Hz/sec drift rate. Closer inspection of the lower third reveals alternating FSK-like blips with a 1.2 Hz delta and a repetitive periodicity of 7.1 seconds. The consistent spacing and periodicity suggest that this is not statistical noise.<br />
<br />
Here is a signal which is -75 kHz left of Hydrogen peak at 1420 + 0.415107 = 1420.415107 MHz decimated by 4096. Note Hz=2X.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiURaQY-xyg4z4tTamkMw6FcRFundicYPCTV8P-ESiNoRMyZKtpCPmuQge5-7cswo3IejmUlGSSTNRuVmAnkxsUC2zRRJ9L7mUPrbMikaDn2yVIvpdtScRYYHq9pa7XTdTqpCty/s1600/1420+%252B415107+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5547725183594788050" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiURaQY-xyg4z4tTamkMw6FcRFundicYPCTV8P-ESiNoRMyZKtpCPmuQge5-7cswo3IejmUlGSSTNRuVmAnkxsUC2zRRJ9L7mUPrbMikaDn2yVIvpdtScRYYHq9pa7XTdTqpCty/s400/1420+%252B415107+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>Looks like scatter noise. Could be caused by multipath. Measuring drift rate is not possible.<br />
<br />
Here is the very strong signal on the far right of the spectrum edge at 1420 + 4.315733 = 1424.315733 MHz decimated by 4096. Note Hz=4X.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixx2PN7p3cDxbbKRioxzvSHwE7RRuQY6Y1256w_XHGhmAYszpYuXdBXWKa_fc2d-5P9ukXcCWKhH8YiImU8MgARVogFlymWoslIWPEbtRffYoCdZbs_rYVtjzuKHPyYwMmlaWr/s1600/1420+%252B4315733+Hz+spectrogram.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545860224066781570" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixx2PN7p3cDxbbKRioxzvSHwE7RRuQY6Y1256w_XHGhmAYszpYuXdBXWKa_fc2d-5P9ukXcCWKhH8YiImU8MgARVogFlymWoslIWPEbtRffYoCdZbs_rYVtjzuKHPyYwMmlaWr/s400/1420+%252B4315733+Hz+spectrogram.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
This is a stationary pulsing tone. Several faint harmonic lines are visible on both sides of the main tone. Here is the Average display with the frequency axis zoomed out one notch.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwRGerp6tWMIG8uJXanPVyxSMMOAohsnJ5nDTkm8MUeLd3r7wO_NSD6CsRzBWV4SnNXPFXVCSamKoijCIaTnDWyGxHph9Lb8XOm4X-0asDhImWnNWfbJumyMzpZPBoxT5gauIT/s1600/1420+%252B4315733+Hz+average.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545861201349624962" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwRGerp6tWMIG8uJXanPVyxSMMOAohsnJ5nDTkm8MUeLd3r7wO_NSD6CsRzBWV4SnNXPFXVCSamKoijCIaTnDWyGxHph9Lb8XOm4X-0asDhImWnNWfbJumyMzpZPBoxT5gauIT/s400/1420+%252B4315733+Hz+average.png" style="cursor: pointer; display: block; height: 158px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The harmonics are at ±50, ±73, ±120, and ±200 Hz which are all very suspicious values. Here is a spectrogram with the I&Q channels using the Histogram <a href="http://baudline.com/manual/channel_mapping.html#transform">transform</a>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYWZ5Vls2-3bQK5cf1Y_NCNnNPk6zgBO4v1d66t45Gt742G6biVUPwtm0s937x73CBL-6bK2Dvd_TELHSb5-5XxMf9Kf8EHreB8FXv1v3wXXSJVNCljN5-59JxQhG7WyeT__ON/s1600/1420+%252B4315733+Hz+spectro+histogram.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545865630092098258" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYWZ5Vls2-3bQK5cf1Y_NCNnNPk6zgBO4v1d66t45Gt742G6biVUPwtm0s937x73CBL-6bK2Dvd_TELHSb5-5XxMf9Kf8EHreB8FXv1v3wXXSJVNCljN5-59JxQhG7WyeT__ON/s400/1420+%252B4315733+Hz+spectro+histogram.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The strong pulsing tone, ±50 and ±73 Hz harmonics, and wandering I&Q Histogram spectrogram were all seen in the <a href="http://baudline.blogspot.com/2010/09/setiquest-kepler-4b-redux.html">Kepler-4b redux</a> analysis with the -2422400 Hz signal. I suspect both were caused by the same distortion phenomena that is internal to the ATA. The Kepler-4b redux dataset was recorded almost 5 months prior.<br />
<br /></div>
<div>
<br /></div>
<div>
<span class="Apple-style-span" style="font-size: x-large;">2008 MHz</span></div>
<div>
sqrt(2) * 1420 = 2008.</div>
<div>
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyFzP7y1OyZUQz_ggqTqFE0N4E3JJhy1mi2c78jvGbGEgq-JQaYS2WZz-UoeHVVbxPREN0wm5ImcqvVzFc0TWnVXG8CQlANRMZVue-BudV-n_ytTd9VwwJ90ebi0Sjoo_aZ-t1/s1600/2008+average.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545099418529196898" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyFzP7y1OyZUQz_ggqTqFE0N4E3JJhy1mi2c78jvGbGEgq-JQaYS2WZz-UoeHVVbxPREN0wm5ImcqvVzFc0TWnVXG8CQlANRMZVue-BudV-n_ytTd9VwwJ90ebi0Sjoo_aZ-t1/s400/2008+average.png" style="cursor: pointer; display: block; height: 169px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Here is the signal at 2008 - 3.166908 = 2004.833092 MHz decimated by 4096.</div>
<div>
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5UEEh4LKG0xL59mvgPJfI2BHZryGV7eCcNo0gQxpvEPh2zEUInstWGg0anBh0YMwSPc771QqgoDfhzPyR2BNoG-W8nbXRrHBhSUPl9FMNXidUIlEAWiB7CkGstaVbcNKahhpZ/s1600/2008+-3166908+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545127200975553026" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5UEEh4LKG0xL59mvgPJfI2BHZryGV7eCcNo0gQxpvEPh2zEUInstWGg0anBh0YMwSPc771QqgoDfhzPyR2BNoG-W8nbXRrHBhSUPl9FMNXidUIlEAWiB7CkGstaVbcNKahhpZ/s400/2008+-3166908+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This faint noise signal shifts -12 Hz in a fairly fast transition that last 101 seconds. At first this signal appears to be stationary but each section has a slight -0.0087 Hz/sec drift rate. A higher resolution signal is required to be certain but this has a classic Doppler flyby shape I often see with acoustic recordings of planes and helicopters.<br />
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Here is the signal at 2008 - 3.160508 = 2004.839492 MHz.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA9RFkCXAqf2-X6wdvHQq82Qz_itTJIaOEvrlTs-B2nypjJcAVZzbdg90Dzq2R8kxlKQLwuUkxIZu8rnmV4gxrWnh0VzNuI96Sb5YJII4tuvLxxshk8IMTFhponuK4J4GiX3jk/s1600/2008+-3160508+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545138020178724210" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA9RFkCXAqf2-X6wdvHQq82Qz_itTJIaOEvrlTs-B2nypjJcAVZzbdg90Dzq2R8kxlKQLwuUkxIZu8rnmV4gxrWnh0VzNuI96Sb5YJII4tuvLxxshk8IMTFhponuK4J4GiX3jk/s400/2008+-3160508+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This signal looks like the two-tone Doppler flyby above but it is +6400 Hz to the right in frequency and it has more well defined pulsing. Using baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> a 26.3 second pulse rate was measured. The pulses before the flyby are also time aligned to those after.<br />
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Here is the signal at 2008 - 2.251751 = 2005.748249 MHz decimated by 4096. Note Hz=2X.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfdWgMVvcYihXWDrQImo6hpE8j9FQ1ogmcDPxhwnRn_4eY_p-qPf8H6xKk92aRgXjOCuRvD4NGiSpk7GTiMMISJZMNVwH7_yGZiOXx7HrShDy6P-YgbLHG_kFJGPqFKHbxO_3S/s1600/2008+-2251751+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545100841984939698" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfdWgMVvcYihXWDrQImo6hpE8j9FQ1ogmcDPxhwnRn_4eY_p-qPf8H6xKk92aRgXjOCuRvD4NGiSpk7GTiMMISJZMNVwH7_yGZiOXx7HrShDy6P-YgbLHG_kFJGPqFKHbxO_3S/s400/2008+-2251751+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This strange looking signal is about 2 Hz wide and it switches between two different linear drift rates. The net drift rate of -53 Hz / 579 seconds = -0.092 Hz/sec is composed of a slower -0.026 Hz/sec rate and a faster -0.21 Hz/sec rate. Baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> show that the pulsing globs line up nicely with a 51 second periodicity spacing.<br />
<br />
Here is the signal at 2008 - 2.184533 = 2005.815467 MHz.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJO3aOQK1fbmhOoDB1HVXSuwaORt9YyP20ijQTlQrl2AE-jS_42ea15CxHbNVJ12EiL5xt2_0TPI0qtpIwCZM9mTn1m2RMtn_MXYrjTbUvnOV7zQUVKopkm3IRqbASx2cy_caU/s1600/2008+-2184533+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545141928341540274" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJO3aOQK1fbmhOoDB1HVXSuwaORt9YyP20ijQTlQrl2AE-jS_42ea15CxHbNVJ12EiL5xt2_0TPI0qtpIwCZM9mTn1m2RMtn_MXYrjTbUvnOV7zQUVKopkm3IRqbASx2cy_caU/s400/2008+-2184533+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>Stationary signal with zero drift rate. Repeated pulsing groups suggest signal could contain modulated content.<br />
<br />
Here is the signal at 2008 - 2.177574 = 2005.822426 MHz decimated by 4096. Note Hz=2X.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkk35rBFN4cIkEM6Zb2C_NVmqEa11giIpgDYjaAVZ4-GRS9KXrtwIEphLoSZAOlnVcnX-VV0qCjUupafvZK7POqw90MQaqM-BeTiC5TpuGnAJ6T0juc-LPcc3ENf8zn3whF8YQ/s1600/2008+-2177574+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545175026228103970" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkk35rBFN4cIkEM6Zb2C_NVmqEa11giIpgDYjaAVZ4-GRS9KXrtwIEphLoSZAOlnVcnX-VV0qCjUupafvZK7POqw90MQaqM-BeTiC5TpuGnAJ6T0juc-LPcc3ENf8zn3whF8YQ/s400/2008+-2177574+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
This is a weaker version of the -2251751 Hz signal we saw above.<br />
<br />
Here is the signal at 2008 - 2.103398 = 2005.896602 MHz decimated by 4096. Note Hz=2X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxfCa4qUD3Br0Y284SVuQ8uWnIfP1p64EkvCQOoupu1NEY_wuj1AWx8-3J1THMozMLnX9sX6cV-jUZtQwwFhFcEqaDhdnFEOMJaYxSH1zfo8vKB2nWnGn6VG1-pEHkcqo59tRK/s1600/2008+-2103398+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545168369645150674" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxfCa4qUD3Br0Y284SVuQ8uWnIfP1p64EkvCQOoupu1NEY_wuj1AWx8-3J1THMozMLnX9sX6cV-jUZtQwwFhFcEqaDhdnFEOMJaYxSH1zfo8vKB2nWnGn6VG1-pEHkcqo59tRK/s400/2008+-2103398+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Another weaker version of the signal we saw above.<br />
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Here is the signal at 2008 - 1.948203 = 2006.051797 MHz decimated by 4096. Note Hz=8X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoRgf14SvSqPrbeyq-wyYzaVCWl3OTrMaRbIQlncrYIs9IQ6infPBUzN8xjNTOd2PDq67jDiHOlexzTe5VxQRKltJ6OOBlnd8NgJlE6Mc92wZzUoGPph8mhc9PVytUTIaJDFSs/s1600/2008+-1948203+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545517600785453378" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoRgf14SvSqPrbeyq-wyYzaVCWl3OTrMaRbIQlncrYIs9IQ6infPBUzN8xjNTOd2PDq67jDiHOlexzTe5VxQRKltJ6OOBlnd8NgJlE6Mc92wZzUoGPph8mhc9PVytUTIaJDFSs/s400/2008+-1948203+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Narrow band noise-like pulses. Drift rate of -110 Hz / 271 seconds = -0.406 Hz/sec. The pulse bursts line up with a 87 second periodicity.<br />
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Here is the signal at 2008 + 1.094480 = 2009.094480 MHz decimated by 4096. Note Hz=8X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPakjxq1W8Sey97c82ATU0CieMbwGpNxSjdnZY6snZcAAyXpfj9ufA48e2rdRhTA0heWbmSlUCHx0-eLk6r_z_DjOgcxU9fdClsoUPUVbjSv5k1-TDGWtrdZ3XSUbwbKBTRdrs/s1600/2008+%252B1094480+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5545526553917091746" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPakjxq1W8Sey97c82ATU0CieMbwGpNxSjdnZY6snZcAAyXpfj9ufA48e2rdRhTA0heWbmSlUCHx0-eLk6r_z_DjOgcxU9fdClsoUPUVbjSv5k1-TDGWtrdZ3XSUbwbKBTRdrs/s400/2008+%252B1094480+Hz.png" style="cursor: pointer; display: block; height: 367px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Drift rate of 240 Hz / 579 seconds = 0.415 Hz/sec. The previous signal above had a similar drift rate but looked completely different. Measured a periodicity of 52 seconds which matches that seen in the -2251751 Hz signal. That signal had the same periodicity but a quarter of the drift rate. It is interesting that this signal shares characteristics with two different signals, they are clearly related but not exactly.<br />
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<a href="http://www.blogger.com/blogger.g?blogID=19780926" name="3991"></a><span class="Apple-style-span" style="font-size: x-large;">3991 MHz</span></div>
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This frequency is expected to be a "bad band" filled with lots of C-band satellite signals.</div>
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<span class="Apple-style-span" style="color: #0000ee;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjS7AJe-5WDfqEqcbh1fb9Hi-fKyRQfNYLaJM4Tk6IAQcWs1VT4F4w4aMTOjyUwEbSHfrf485DGTGs8MjWmrEahJDzB4j6gllmEGfW7Wn7yGVuaiJROwY6j7V1gcFV9DGkaQrDc/s1600/Lagrange-4_3991+4M+screenshot.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5536220291927936994" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjS7AJe-5WDfqEqcbh1fb9Hi-fKyRQfNYLaJM4Tk6IAQcWs1VT4F4w4aMTOjyUwEbSHfrf485DGTGs8MjWmrEahJDzB4j6gllmEGfW7Wn7yGVuaiJROwY6j7V1gcFV9DGkaQrDc/s400/Lagrange-4_3991+4M+screenshot.png" style="cursor: pointer; display: block; height: 320px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a></span></div>
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This signal's bandwidth is 2.5 MHz wide. The spectrogram and Average spectrum look to be filled with an incredible number of signals. Let's zoom into the frequency axis of the Average spectrum:</div>
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<span class="Apple-style-span" style="color: #0000ee;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1hU3is8hoWRmJNU_NWAt_2gyVyn1fhjuyaVGCebcBC4WxKTCh99Iur9BJZ9EJwNivJi4iQMRhiM870YE24Zjs54f5YL66bFQa3hq3aP0QWX_VBW4_qnRw-uno1tvKXrNXs4Cl/s1600/3991+average+64X.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5536260347855136930" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1hU3is8hoWRmJNU_NWAt_2gyVyn1fhjuyaVGCebcBC4WxKTCh99Iur9BJZ9EJwNivJi4iQMRhiM870YE24Zjs54f5YL66bFQa3hq3aP0QWX_VBW4_qnRw-uno1tvKXrNXs4Cl/s400/3991+average+64X.png" style="cursor: pointer; display: block; height: 171px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a></span></div>
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There are thousands of narrow well defined signals everywhere you look in the spectrum Let's zoom in some more:</div>
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<span class="Apple-style-span" style="color: #0000ee;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVWF4GbbYt36DpHODD27-T8seyYxvwpOfoGqpcurGnd4Rmgzp2iid9SrrjT64jVSIOcIlVU23wRfPzj_Etp3aK2MhyuilYor1U2SYnTrKqcghFJVv1A-beq2uzRRlVMUi9ZFfw/s1600/3991+average+16X.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5536261377993288258" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVWF4GbbYt36DpHODD27-T8seyYxvwpOfoGqpcurGnd4Rmgzp2iid9SrrjT64jVSIOcIlVU23wRfPzj_Etp3aK2MhyuilYor1U2SYnTrKqcghFJVv1A-beq2uzRRlVMUi9ZFfw/s400/3991+average+16X.png" style="cursor: pointer; display: block; height: 171px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a></span></div>
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Using baudline's <a href="http://baudline.com/manual/measurements.html#fundamental_Hz_dB_PSD">fundamental Hz</a> measurement window the delta between peaks was accurately measured to be 1267.226 Hz. That is an interesting value because ...</div>
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Next let us decimate by 4096 and zoom into the strongest signal peak at 1502 kHz.</div>
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<span class="Apple-style-span" style="color: #0000ee;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdeeCtRtcffyZn4CKV-mxPEWgz4tOWO9K36GJ7fFcjZR_tN3RM0mRBTq9NpVRJJpbLLSUGGsuJOvs4YrzgxGAGsWODJybRQ8RZm9Im2GDpA3FJu9byr31SqY7b4R0ZPqlCWVIn/s1600/Lagrange-4_3991+1502kHz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5536561790762494370" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdeeCtRtcffyZn4CKV-mxPEWgz4tOWO9K36GJ7fFcjZR_tN3RM0mRBTq9NpVRJJpbLLSUGGsuJOvs4YrzgxGAGsWODJybRQ8RZm9Im2GDpA3FJu9byr31SqY7b4R0ZPqlCWVIn/s400/Lagrange-4_3991+1502kHz.png" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a></span></div>
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<span class="Apple-style-span" style="color: #0000ee;"><br /></span></div>
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Slowly drifting to the left with a general drift rate of -0.91 Hz / 295 seconds = -0.0033 Hz/second. The signal erratically jumps between several discrete frequencies with deltas of {∆ 0.5, 1.0, 1.4, 3.2 Hz}. This signal is clearly modulated. Using the <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> a symbol rate of 1 / 2.783 seconds = 0.359 symbols/second is measured.</div>
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Randomly spot checking 20 of the tone peaks reveals the same shape with varying amplitudes. So I believe that there are thousands of copies of this same signal. This could be caused by AM modulation, distortion in the ATA signal chain, or it could be a unique characteristic of this modulation scheme.</div>
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Listen to this modulated signal in the following video. Select 720p HD and fullscreen for the best resolution.</div>
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<center>
<object height="336" width="420"><param name="movie" value="http://www.youtube.com/v/hS5iM78defg?fs=1&hl=en_US&rel=0&hd=1&color1=0x234900&color2=0x4e9e00"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/hS5iM78defg?fs=1&hl=en_US&rel=0&hd=1&color1=0x234900&color2=0x4e9e00" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="336" width="420"></embed></object></center>
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Something else extremely interesting is going on with this signal. Here is the autocorrelation spectrogram of the same signal seen above decimated by another factor of 64 for a total decimation ratio of 262144.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisDqgmj9orsKobSzV6rlV6OcvAFWso1AKiftpXzZoXwVgwBy9_Geo2wcaJJj-mTJYNdS9KOh0kp1dDlbuKHDWj7v9jTAyKl2JCz_0IkMkOoSPs-MtSTVXt1P_O0JHZ4CKHJcts/s1600/3991+spectrogram+2M+autocorrelation+33.3333+%252B1502346+Hz.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5549244878563359762" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisDqgmj9orsKobSzV6rlV6OcvAFWso1AKiftpXzZoXwVgwBy9_Geo2wcaJJj-mTJYNdS9KOh0kp1dDlbuKHDWj7v9jTAyKl2JCz_0IkMkOoSPs-MtSTVXt1P_O0JHZ4CKHJcts/s400/3991+spectrogram+2M+autocorrelation+33.3333+%252B1502346+Hz.png" style="cursor: pointer; display: block; height: 400px; margin: 0px auto 10px; text-align: center; width: 372px;" /></a>The two patterns of interest are the strange shapes in the middle the 6+ holes near the bottom. They signify a more complex structure than you would expect from a drifting random walk. Similar shapes and holes were also seen in several other baudline-setiQuest <span id="main" style="visibility: visible;"><span id="search" style="visibility: visible;">analyses</span></span> such as the two Kepler-4 blog posts.<br />
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Here is the spectrogram of the blip Fourier transform in phase space.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5lO_RnjHg_fKWuCb05hKkJ-gintOW9PXk7NCn3OE4i6nicGZk2f9mb2VQ2waL7-pWgl9gXNhFSA8CYHBGvfcmOv79Pf2V-1nOk_R5h8ecku0Ou8QLI5ajpw33taXHJeX5SCsL/s1600/3991+blip+phase+spectrogram.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5549249561000305298" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5lO_RnjHg_fKWuCb05hKkJ-gintOW9PXk7NCn3OE4i6nicGZk2f9mb2VQ2waL7-pWgl9gXNhFSA8CYHBGvfcmOv79Pf2V-1nOk_R5h8ecku0Ou8QLI5ajpw33taXHJeX5SCsL/s400/3991+blip+phase+spectrogram.png" style="cursor: pointer; display: block; height: 324px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Look along the vertical center-line (arrow) and notice the evenly spaced black holes near the bottom. Their periodic spacing measurement is 5.81 seconds for 7 consecutive major feature changes. This distribution is too uniform to be a statistic fluke. They signify 180º phase shifts which suggest a BPSK like modulation.<br />
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Here is a plot of the Autocorrelation transform using the Average window of the full bandwidth signal.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdAEBCZjVtIPeq-nmxMFi_Alqz4b4Zmd9Lt1_97xlSwbfImEoLchfrKX0oD61Gu8wL4uBknEYcps6GctBowMXFElbW76WbDmx_hGQbXy_fM-vMkMaUeIKmD9VvwR8JB4-tLJyV/s1600/3991+average+2M+autocorrelation.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5548093246225633522" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdAEBCZjVtIPeq-nmxMFi_Alqz4b4Zmd9Lt1_97xlSwbfImEoLchfrKX0oD61Gu8wL4uBknEYcps6GctBowMXFElbW76WbDmx_hGQbXy_fM-vMkMaUeIKmD9VvwR8JB4-tLJyV/s400/3991+average+2M+autocorrelation.png" style="cursor: pointer; display: block; height: 168px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicP6-xpJmrMr465UTlkr-nOPPAzLwljkZ0ZFOgeTmaYqG9R_0yWDLQAQJSjhUt_5ZI1MXZ8-OrMzSMYmb4Kc7ANXv3Fwtat-PVq6SpecXznyv5hzd8ndtn7kiArYGIo9yARDdS/s1600/3991+averge+2M+autocorrelation.png"><br /></a>The evenly spaced spikes represent that a repetitive pattern is present. This shape suggests the signal is direct-sequence spread spectrum (DSSS) and possibly CDMA. The spacing between autocorrelation peaks is 1 / 789.07 us = 1267.3 Hz which interestingly is within 0.1 Hz of the spectral measurement above.</div>
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Here is an autocorrelation spectrogram.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTiohuQ3-Iw_0HUN7wOE04WZXVlHDxNT_SMjN2QSIjNHQY_S2QRxniTLwOaVAvl8fEgKZG9XGompvpgHG1YN7N0U4DeDP-NTrAeDNtOkMfo7WK-3vITbghsxtXWbwAOpAOlr87/s1600/3991+spectrogram+2M+autocorrelation.png"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5549242182730673282" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTiohuQ3-Iw_0HUN7wOE04WZXVlHDxNT_SMjN2QSIjNHQY_S2QRxniTLwOaVAvl8fEgKZG9XGompvpgHG1YN7N0U4DeDP-NTrAeDNtOkMfo7WK-3vITbghsxtXWbwAOpAOlr87/s400/3991+spectrogram+2M+autocorrelation.png" style="cursor: pointer; display: block; height: 374px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a></div>
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The vertical dash-dot patterns represent changing bits (groups actually). Any common patterns you see are likely repeating header or idle sequences.<br />
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<span class="Apple-style-span" style="font-size: x-large;">Conclusion</span></div>
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The Lagrange-4 datasets contained an incredible number of unique signals. Drifting random walks were a common theme in the 1420 MHz band while 2008 MHz was mostly populated with variations of a wider band Doppler flyby signal. Many of these signals had modulated features. Determining the source of these unknown signals is not really possible with the available information. This fairly sums up the challenge of SETI; detecting weak signals is easy, determining extraterrestrial origin is difficult.<br />
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The 3991 MHz band contained one 2.5 MHz wide signal that I suspect is CDMA. In the comments below a reader named Martin posted some extremely interesting information about the STEREO (Solar TErrestrial RElations Observatory) NASA satellites at the L4 and L5 positions (see plot below).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRue7z4WuKlMf8aECpXULBHoRJzzSAlPE8RsLqSm_4ADAyW8bb0Nb_a9ytOdSEm2R1vpZHYv7_PaYylw4Q_cGy5rrxjlc97CXWyAVST_-QVESi5eAi_HsZGRQAZTisx3LwGucs/s1600/positions+of+STEREO+AB+2010-10-8.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRue7z4WuKlMf8aECpXULBHoRJzzSAlPE8RsLqSm_4ADAyW8bb0Nb_a9ytOdSEm2R1vpZHYv7_PaYylw4Q_cGy5rrxjlc97CXWyAVST_-QVESi5eAi_HsZGRQAZTisx3LwGucs/s320/positions+of+STEREO+AB+2010-10-8.png" width="217" /></a></div>
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Martin mentions STEREO having a 633.245 bps data rate at 8.4 GHz. Twice this data rate is 1266.490 bps which is very close to the 1267.226 Hz spectral value and the 1 / 789.07 us = 1267.3 Hz autocorrelation rate I measured. The average error is 0.75 Hz which seems slightly greater than the accuracy level I felt baudline measured but since this signal is wiggling around by almost ±2 Hz it is in the realm of being a plausible match. Explaining how such a low baud rate signal gets down-converted by 4.4 GHz and expanded into a CDMA-like 2.5 MHz wideband signal is more difficult. In any event, this match is potentially an amazing discovery that should help in understanding the distortion characteristics of the ATA. Thank you Martin.<br />
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There were too many signals in the Lagrange-4 datasets to be able provide the quality of coverage each signal deserved. This blog post is the last time that I will attempt an exhaustive analysis of all the signals in a data set. It is a quantity vs. quality trade-off. Future baudline-setiQuest blog posts will focus on a single feature of interest. I also plan on incorporating more video clips so let me know what you think of them in the comments and how they might be more useful.</div>
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<span class="Apple-style-span" style="font-size: x-large;">Links</span></div>
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<ul>
<li><a href="http://setiquest.org/forum/topic/baudline-analysis-lagrange-4">http://setiquest.org/forum/topic/baudline-analysis-lagrange-4</a></li>
<li><a href="http://setiquest.org/forum/topic/new-datasets-posted#comment-1416">http://setiquest.org/forum/topic/new-datasets-posted#comment-1416</a></li>
<li><a href="http://map.gsfc.nasa.gov/mission/observatory_l2.html">http://map.gsfc.nasa.gov/mission/observatory_l2.html</a></li>
<li><a href="http://www.esa.int/esaSC/SEMM17XJD1E_index_0.html">http://www.esa.int/esaSC/SEMM17XJD1E_index_0.html</a></li>
<li><a href="http://www.nasa.gov/stereo/">http://www.nasa.gov/stereo/</a></li>
<li><a href="http://www.amsat.org/amsat/articles/g3ruh/127.html">http://www.amsat.org/amsat/articles/g3ruh/127.html</a></li>
</ul>
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<span class="Apple-style-span" style="font-size: 85%;">Data licensed through <a href="http://www.seti.org/">SETI</a>.</span></div>
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<span class="Apple-style-span" style="font-size: 85%;">Software licensed through <a href="http://www.sigblips.com/">SigBlips</a>.</span></div>
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baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com3tag:blogger.com,1999:blog-19780926.post-57269140693485523362010-09-26T14:12:00.000-07:002010-11-17T15:43:39.164-08:00setiQuest Kepler-4b reduxThe discovery of an extremely interesting <a href="http://baudline.com/manual/glossary.html#FSK">FSK</a> modulated signal was reported in my <a href="http://baudline.blogspot.com/2010/04/setiquest-kepler-exo4-1420-mhz.html">setiQuest Kepler-Exo4 1420 MHz</a> blog entry back on April 24 2010. This finding generated a great deal of excitement and skepticism. Was it a real extraterrestrial transmission from the exoplanet Kepler-4b or was it just local <a href="http://baudline.com/manual/glossary.html#RFI">RFI</a>? The SETI Institute decided to follow up and take a second look at the Kepler-04 target in May 15 2010. Two new datasets of "good" observations were released <a href="http://setiquest.org/forum/topic/new-datasets-posted#comment-1154">a couple days ago</a>.<br /><br />The <a href="http://www.baudline.com/">baudline signal analyzer</a> is going to explore this setiQuest Kepler-4b redux data. The base frequency of the two data files are 1418.0 and 1420.0 MHz with an 8.7381 MHz bandwidth. The format is the familiar signed 8-bit <a href="http://baudline.com/manual/glossary.html#quadrature">quadrature</a> data with a sample rate of 8738133.333 samples/second.<br /><br />The following command line was used to stream the Kepler-4b data files into baudline:<br /><br /><span style="font-size:85%;"><span style="font-family:courier new;">cat 2010-05-14-kepler04-3* | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133 -fftsize 65536 -pause -utc 0<br /></span></span><br />First the kepler04-3 dataset will be analyzed and then the kepler04-4 dataset.<br /><div><br /><br /><span style="font-size:180%;">Kepler04-3</span><br /><div>Date: May-14-2010<br />Start time: <b>10:50</b><br />Freq: <b>1418.0</b> MHz<br />RA,Dec: 19.041021,50.135753<br /><br />The kepler04-3*.dat files are the first data set in this redux. A <a href="http://baudline.com/manual/equalization.html#windowing">Welch windowed</a> 65536 point FFT for a 266.67 Hz/bin resolution was used to create the image below. Click on image for a larger view.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6g217rWGzDMHHWNhGS_n-iwS8mQ0jCfVhspb-JMuzjQ_Pu51oOfUr2ZCIq623Q75xTQI2d1bZgB5VJtHKwCpTVphTiI8BF17VnEPkVU0jtBYFwkxXNoNYpjxUga51TzWY25qa/s1600/kepler04-3+screen-capture.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6g217rWGzDMHHWNhGS_n-iwS8mQ0jCfVhspb-JMuzjQ_Pu51oOfUr2ZCIq623Q75xTQI2d1bZgB5VJtHKwCpTVphTiI8BF17VnEPkVU0jtBYFwkxXNoNYpjxUga51TzWY25qa/s400/kepler04-3+screen-capture.png" alt="" id="BLOGGER_PHOTO_ID_5521322674449519554" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 320px;" border="0" /></a><br />Here is the Average spectrum from a prototype version of baudline that has more sensitivity.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMvRyCUcxlDIGtVyh4kJOHuCukLaEM3fsdSTWt3Fy92MeaIXRe5f8ge6PQjqhBeS9ATV79Hv1w07ud2y3KUGqlKmOWES7VYsxJBsALSZvN7W-i3kwd7oxMZMxv6j4Kop8VNlnh/s1600/kepler04-4+average+4M.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 154px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMvRyCUcxlDIGtVyh4kJOHuCukLaEM3fsdSTWt3Fy92MeaIXRe5f8ge6PQjqhBeS9ATV79Hv1w07ud2y3KUGqlKmOWES7VYsxJBsALSZvN7W-i3kwd7oxMZMxv6j4Kop8VNlnh/s400/kepler04-4+average+4M.png" alt="" id="BLOGGER_PHOTO_ID_5539993971677578450" border="0" /></a><br />Targets:<br /><ul><li>-2422400 Hz | 215 sigma | "off the top"<br /></li><li>-1312794 Hz | 6 sigma<br /></li><li>-1274844 Hz | 7 sigma<br /></li><li>-44514 Hz | 4 sigma</li><li>-38376 Hz | 4 sigma<br /></li><li>+2044295 Hz | 22 sigma | "left of Hydrogen"<br /></li><li>+2416146 Hz | 10 sigma | "in Hydrogen"<br /></li><li>+3008373 Hz | 7 sigma | "right of Hydrogen"<br /></li></ul>There are several signals within the +2044295 Hz "left of Hydrogen" peak so let's decimate by 256 and see what <a href="http://baudline.com/manual/process.html#auto_drift">Auto Drift</a> can find:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuc9MK1cO0BvKXClPgT9WaZWDr-FueBzsgIYTnv1t1GO_tSTw19nsgVPt_7mrKvkD6xs-sUh1NodBT2SNfvBs_s2O7gOsUtqO2LzKhW7r1DWvhAK1s_v94vCpmW68v6_xGmzTM/s1600/kepler04-4+average+d256.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 157px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuc9MK1cO0BvKXClPgT9WaZWDr-FueBzsgIYTnv1t1GO_tSTw19nsgVPt_7mrKvkD6xs-sUh1NodBT2SNfvBs_s2O7gOsUtqO2LzKhW7r1DWvhAK1s_v94vCpmW68v6_xGmzTM/s400/kepler04-4+average+d256.png" alt="" id="BLOGGER_PHOTO_ID_5539995208434716786" border="0" /></a><br />Compare the green and purple spectrum curves. Auto drift increases the strength of drifting signals, reduces the variance of the noise floor, and allows the drift rate to be queried with the <a href="http://baudline.com/manual/measurements.html#auto_drift_rate">auto drift rate</a> measurement window.<br /><br />Drifting Targets:<br /><ul><li>+2025472 Hz | 22 sigma | +0.0447 Hz/s</li><li>+2030395 Hz | 6 sigma | +0.0249 Hz/s</li><li>+2031496 Hz | 7 sigma | -0.5453 Hz/s</li><li>+2034730 Hz | 14 sigma | -0.0976 Hz/s | "LSB?"<br /></li><li>+2034911 Hz | 30 sigma | -0.2942 Hz/s | "carrier?"<br /></li><li>+2035122 Hz | 14 sigma | +0.0137 Hz/s | "USB?"<br /></li><li>+2036686 Hz | 12 sigma | -0.1494 Hz/s</li><li>+2037900 Hz | 11 sigma | -0.3151 Hz/s</li><li>+2038257 Hz | 4 sigma | -0.1672 Hz/s</li><li>+2038767 Hz | 45 sigma | -0.0447 Hz/s</li><li>+2038960 Hz | 7 sigma | -0.0991 Hz/s</li><li>+2040367 Hz | 16 sigma | +0.0417 Hz/s</li><li>+2044250 Hz | 78 sigma | -0.1855 Hz/s | "left of Hydrogen"</li><li>+2045996 Hz | 14 sigma | +0.3710 Hz/s</li></ul>Now let's zoom in, take a look around, and see what we can find.<br /><br /><br /><span style="font-size:180%;">Hydrogen has Sidebands</span><span class="Apple-style-span" style="font-size:x-large;"><br /></span>Hydrogen is the largest peak in the center (+2526 kHz) of the <a href="http://baudline.com/manual/average.html#average">Average</a> display below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB-CD2G6hW6xlNB26k_eatpO4IBBi4GSOAVHn2du40FiK_DavMe5usq4qZdI4R_ZbMfqr04lDqkSlMXEz5HR_oVQ02o2WeqnhE1fBgTeZQDcIhrnHQ1tMhKqgxoiQHCDGT3czt/s1600/kepler04-3+hydrogen+sidebands+average.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB-CD2G6hW6xlNB26k_eatpO4IBBi4GSOAVHn2du40FiK_DavMe5usq4qZdI4R_ZbMfqr04lDqkSlMXEz5HR_oVQ02o2WeqnhE1fBgTeZQDcIhrnHQ1tMhKqgxoiQHCDGT3czt/s400/kepler04-3+hydrogen+sidebands+average.png" alt="" id="BLOGGER_PHOTO_ID_5520657817713273650" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 146px; color: rgb(0, 0, 238);" border="0" /></a><br />Adjusting for Hydrogen's slightly lopsided shape moves the center of mass -14 kHz to the left. When this offset is applied the corrected center of mass sits directly in the middle of the two tones with a delta of ±483 kHz.<br /><br /><br /><span style="font-size:180%;">-2422400 Hz</span><br /></div><div>Very strong tone. <a href="http://baudline.com/manual/glossary.html#decimation">Decimating</a> by 4096.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMHYVv54GaScbj9LbDNY7_3lG6Ejp9xmZp7T62sycyPBN00PRlKWP2rB4WaC4a0Xenyyme8DXw5QpVJGxK2ldrw5FikoRAogfVa8wyudAV05JTnljNv8sK2oEdapJvxwH350Ni/s1600/kepler04-3+-2422400Hz+average.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMHYVv54GaScbj9LbDNY7_3lG6Ejp9xmZp7T62sycyPBN00PRlKWP2rB4WaC4a0Xenyyme8DXw5QpVJGxK2ldrw5FikoRAogfVa8wyudAV05JTnljNv8sK2oEdapJvxwH350Ni/s400/kepler04-3+-2422400Hz+average.png" alt="" id="BLOGGER_PHOTO_ID_5520576804155669970" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 151px;" border="0" /></a><br />The center tone is measured to be at -2422399.90 Hz. This is a very suspicious number because -2422399.90 / 8738133.33 * 8192 = -2270.99991 which is the whole number -2271 for all practical purposes. I suspect bin[2271] is buried somewhere deep in the ATA <a href="http://baudline.com/manual/glossary.html#DSP">DSP</a> code, possibly as a tuning parameter.<br /><br />The purple sidebands are ±73.95 Hz from the center tone. The green sidebands are ±50.00 Hz from the center tone. The two sets of non-harmonically related sidebands suggest that there are two independent distortion/modulation forces (50 & 74 Hz) at work.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjY6zE0ssLT0Tq9w3eggENpKnh4rCR022ehcqKRLgEUEEw7yZjqgMat4eUs7NS-b_ojpNjfdm42St0fEPnMLRgfZ6BjusTtGvibuqgz9f8kkxcePB1VJ8gynPQQm7Qyh7lT2un/s1600/kepler04-3+-2422400Hz+spectrogram.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjY6zE0ssLT0Tq9w3eggENpKnh4rCR022ehcqKRLgEUEEw7yZjqgMat4eUs7NS-b_ojpNjfdm42St0fEPnMLRgfZ6BjusTtGvibuqgz9f8kkxcePB1VJ8gynPQQm7Qyh7lT2un/s400/kepler04-3+-2422400Hz+spectrogram.png" alt="" id="BLOGGER_PHOTO_ID_5520580346708368386" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 368px;" border="0" /></a><br />A stationary tone with zero drift rate. Four amplitude dropouts of about -14 dB are visible.<br /><br />While baudline was recording this decimated signal I noticed that the <a href="http://baudline.com/manual/histogram.html#histogram">Histogram</a> window underwent some odd and unusual behavior. Here a 3 snapshots:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2IKMZR93mZtSfHkHwgK3uLjg0XcQF7aXOYGY_4fQIkvZvoQxHDnJz-C1n6wc9u9eKbQFMUd6H8Ykjgb2KMGc8VlW9I9PVhTJxd3yvQMqVSVxZjt2a_VBmkxbvt-q1ooS-pT_V/s1600/kepler04-3+-2422400Hz++historgram3.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2IKMZR93mZtSfHkHwgK3uLjg0XcQF7aXOYGY_4fQIkvZvoQxHDnJz-C1n6wc9u9eKbQFMUd6H8Ykjgb2KMGc8VlW9I9PVhTJxd3yvQMqVSVxZjt2a_VBmkxbvt-q1ooS-pT_V/s400/kepler04-3+-2422400Hz++historgram3.png" alt="" id="BLOGGER_PHOTO_ID_5520606928451774274" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 145px;" border="0" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4GBJjusi9BrimCdqb9E25V1Ztb13aIg02tc4HisepqJtkk2AJIMsXCZwGgfNX1_FC2phZm_34Q5D1_ujjY-AIbVS9nycS4Fj0B-h1pbUhdUD_b7ItIxPztBt3Yy12JS1_ZTgo/s1600/kepler04-3+-2422400Hz++historgram2.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4GBJjusi9BrimCdqb9E25V1Ztb13aIg02tc4HisepqJtkk2AJIMsXCZwGgfNX1_FC2phZm_34Q5D1_ujjY-AIbVS9nycS4Fj0B-h1pbUhdUD_b7ItIxPztBt3Yy12JS1_ZTgo/s400/kepler04-3+-2422400Hz++historgram2.png" alt="" id="BLOGGER_PHOTO_ID_5520606918087757490" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 145px;" border="0" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEie4RbhHB2lsSAFenRwnOgeWl1fpNqKetXfmb-ymc32NoncbFd3iQ0dc25BdUA_tVWqu4K-_WD3jEL63ADfQ8NtuM0F5jOJdzH9gWrgN0Ebwn9USWs5m6DXE5jmhwAerCM1fZRw/s1600/kepler04-3+-2422400Hz++historgram1.png"></a></div><div><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEie4RbhHB2lsSAFenRwnOgeWl1fpNqKetXfmb-ymc32NoncbFd3iQ0dc25BdUA_tVWqu4K-_WD3jEL63ADfQ8NtuM0F5jOJdzH9gWrgN0Ebwn9USWs5m6DXE5jmhwAerCM1fZRw/s1600/kepler04-3+-2422400Hz++historgram1.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEie4RbhHB2lsSAFenRwnOgeWl1fpNqKetXfmb-ymc32NoncbFd3iQ0dc25BdUA_tVWqu4K-_WD3jEL63ADfQ8NtuM0F5jOJdzH9gWrgN0Ebwn9USWs5m6DXE5jmhwAerCM1fZRw/s400/kepler04-3+-2422400Hz++historgram1.png" alt="" id="BLOGGER_PHOTO_ID_5520606911193937842" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 145px;" border="0" /></a></div><div><br />It looks like the DC value of the quadrature channels is changing. To get a better understanding of this dynamic behavior let us look at the problem from a different perspective. Below is the spectrogram of the Histogram transform. The green and purple colors represent the I & Q channels respectively.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6ip3prBOT9fRc4npgp4pd9Bbxj92A4YDbLnK0R24QEdEw777x9lwIpeYCpMEQ6HJQwqHU5uU53sOsE3x4nMxcW_BScNeVIKvuJ07kJLa8If6Y83wbumZv_RMHW7YXj96jHaT7/s1600/kepler04-3+-2422400Hz++historgram+transform.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6ip3prBOT9fRc4npgp4pd9Bbxj92A4YDbLnK0R24QEdEw777x9lwIpeYCpMEQ6HJQwqHU5uU53sOsE3x4nMxcW_BScNeVIKvuJ07kJLa8If6Y83wbumZv_RMHW7YXj96jHaT7/s400/kepler04-3+-2422400Hz++historgram+transform.png" alt="" id="BLOGGER_PHOTO_ID_5520601927775232578" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 368px;" border="0" /></a><br />One way of interpreting the data is that some sort of strange phasing is at work. Another way of looking at the data is that the quadrature balance is wandering.<br /><br /><br /><span style="font-size:180%;">-1312794 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixJralCNlQXyJXpenGoyqO0yN40NGQdAGn5oUrHv0KQwdYGIHT9YQL3fKcIAqCTs9AfS9C_bfC-LfND_rdULVKsdqgWzWUrb8p6nBjfL965e1xWh-qiHS7OnvTUIK8skRWckFb/s1600/kepler04-4+-1312803+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixJralCNlQXyJXpenGoyqO0yN40NGQdAGn5oUrHv0KQwdYGIHT9YQL3fKcIAqCTs9AfS9C_bfC-LfND_rdULVKsdqgWzWUrb8p6nBjfL965e1xWh-qiHS7OnvTUIK8skRWckFb/s400/kepler04-4+-1312803+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5539924986299615810" border="0" /></a><br />Drifting wideband noise with a -8.92 Hz / 112.3 seconds = -0.0794 Hz/sec drift rate.<br /><br /><br /><span style="font-size:180%;">-1274844 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMmRrldmAqQKk-VDxDwAbpTGfX0XHgvl1DBzoKHUP9uY_Ig_zXyFE20DNYGAZAlqbfvmm6xghIhrv-8rcfEiB9n8PHTTfFBxlOxJVi_fXNopliPkKro6XWsh8AaElZMy_yVybS/s1600/kepler04-3+-1274844+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMmRrldmAqQKk-VDxDwAbpTGfX0XHgvl1DBzoKHUP9uY_Ig_zXyFE20DNYGAZAlqbfvmm6xghIhrv-8rcfEiB9n8PHTTfFBxlOxJVi_fXNopliPkKro6XWsh8AaElZMy_yVybS/s400/kepler04-3+-1274844+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5539935232450848674" border="0" /></a>Non-drifting wideband noise similar to the previous signal above. The scattered high energy blips are about +10 dB above the noise floor.<br /><br /><br /><span style="font-size:180%;">-44514 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6t3TRd6vvBVG8PdNZ1wlJOwYvqltRJiMghWISZxD1bNN6DlQoCGhGaascbAlO3gxI4uRDIcMbqH7zh14Yr-LQ0O5OOb_oni0iALi9zSBiHdSHbu4ziuddeqwlERPMHHS_sJJP/s1600/kepler04-3+-44514+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6t3TRd6vvBVG8PdNZ1wlJOwYvqltRJiMghWISZxD1bNN6DlQoCGhGaascbAlO3gxI4uRDIcMbqH7zh14Yr-LQ0O5OOb_oni0iALi9zSBiHdSHbu4ziuddeqwlERPMHHS_sJJP/s400/kepler04-3+-44514+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5539941766250748114" border="0" /></a><br />More weak non-drifting wideband scatter noise. Four sigma above the noise floor. Not much to see.<br /><br /><br /><span style="font-size:180%;">-38376 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAJD0PnYMHsetLtzXlaw0FFKYDv3Xa4I9NSneywvT6viEcg28ms_NQ1GtdV-V6g9thkk_h4pYdYGHDn7-swnh-ZTsC7Y3kkh_6wSqHoO1xNmTWxAFJRtVTYZ3YBpqSD-ZjePtr/s1600/kepler04-3+-38376+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAJD0PnYMHsetLtzXlaw0FFKYDv3Xa4I9NSneywvT6viEcg28ms_NQ1GtdV-V6g9thkk_h4pYdYGHDn7-swnh-ZTsC7Y3kkh_6wSqHoO1xNmTWxAFJRtVTYZ3YBpqSD-ZjePtr/s400/kepler04-3+-38376+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5539949408650065202" border="0" /></a><br />Another 4 sigma signal. Weak non-drifting wideband scatter noise. Not much to see.<br /><br /><br /><span style="font-size:180%;">+2025472 Hz</span><br />First signal from the Auto Drift target set. Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgikvYmlo2qvnqkOIuRzigC0cWIq1VnQkH6gJDKkKXagKHnZ-TIgeZHZRVICZU7-kvk_JqmmKb38Db0otNd6o-K39FA7Ds_2et2GgWyHNO-OQPEPDI4s75Yi3KRhuaApMGXvREq/s1600/kepler04-3+%252B2025471+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgikvYmlo2qvnqkOIuRzigC0cWIq1VnQkH6gJDKkKXagKHnZ-TIgeZHZRVICZU7-kvk_JqmmKb38Db0otNd6o-K39FA7Ds_2et2GgWyHNO-OQPEPDI4s75Yi3KRhuaApMGXvREq/s400/kepler04-3+%252B2025471+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540209493508651074" border="0" /></a><br />A drifting random walk with a +10.81 Hz / 255.7 seconds = +0.0423 Hz/sec drift rate. Using baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> shows a repetitive 25 Hz frequency bounce. Further inspection shows a roughly 2.5 Hz pulsing.<br /><br /><br /><span style="font-size:180%;">+2030395 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwZwZouiJ7I_7MFvpe5peyrV5qxWaODqwsOo_h0lPhYYn-hcssuXxXQIZ46E0CDHosC0Uq4tDpW-7tHsVO0kq4F7wGmDNq0QXwYpo85osrbFV0cJVVE9UierDgcj7ncy4kQqqq/s1600/kepler04-3+%252B2030395+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwZwZouiJ7I_7MFvpe5peyrV5qxWaODqwsOo_h0lPhYYn-hcssuXxXQIZ46E0CDHosC0Uq4tDpW-7tHsVO0kq4F7wGmDNq0QXwYpo85osrbFV0cJVVE9UierDgcj7ncy4kQqqq/s400/kepler04-3+%252B2030395+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540216082890121314" border="0" /></a><br />A weak drifting random walk with a +5.92 Hz / 255.7 seconds = +0.0232 Hz/sec drift rate.<br /><br /><span style="font-size:180%;"><br />+2031500 Hz</span><br />Decimating by 4096. Note that the frequency axis has been changed to Hz=4X so the entire signal fits on the screen.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibnIzVfa7PJSsT-JMe6IE4KwOs0WDJOwNsXgMO2NO0q8eQN4Z7_kkyvEfH6yg-B7p9OoSDtEbxyckErx6O29RX0trUPLZngkDX9Gs0pbCKDbunG_LQ51cqgAFQaFh7VcDI33ys/s1600/kepler04-3+%252B2031500+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibnIzVfa7PJSsT-JMe6IE4KwOs0WDJOwNsXgMO2NO0q8eQN4Z7_kkyvEfH6yg-B7p9OoSDtEbxyckErx6O29RX0trUPLZngkDX9Gs0pbCKDbunG_LQ51cqgAFQaFh7VcDI33ys/s400/kepler04-3+%252B2031500+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540275154925263650" border="0" /></a><br />A drifting random walk with a -125.26 Hz / 255.7 seconds = -0.4899 Hz/sec drift rate. The periodic bars found a rough periodicity of 28.4 seconds.<br /><br /><br /><span style="font-size:180%;">+2034731 Hz</span><br />This signal looked like a lower sideband (LSB) to a nearby carrier. Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1Cko4QEidCUS_BkAJP2Z2Z5GqQ-YUkZOh7kR5jMK6Q6TeMDSctEz8UWlciqpbEiW_CPEcKB54c7uh8C7JQTtmQJF0FVo4WXNXXSPnq90LxGd9B7PrcsfHKHO251DxCGWWSuu6/s1600/kepler04-3+%252B2034731+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1Cko4QEidCUS_BkAJP2Z2Z5GqQ-YUkZOh7kR5jMK6Q6TeMDSctEz8UWlciqpbEiW_CPEcKB54c7uh8C7JQTtmQJF0FVo4WXNXXSPnq90LxGd9B7PrcsfHKHO251DxCGWWSuu6/s400/kepler04-3+%252B2034731+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540224599797044930" border="0" /></a><br />A drifting random walk with a -24.41 Hz / 255.7 seconds = -0.0955 Hz/sec drift rate. Blip pulsing with a 7.48 second periodicity.<br /><br /><br /><span style="font-size:180%;">+2034913 Hz</span><br />This signal looked like a carrier that had upper and lower sidebands. Decimating by 4096. Note that the frequency axis has been changed to Hz=2X so the entire signal fits on the screen.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPsqq3-g7Oo0K03rW7oozyTaKGoRrabKqeuXteIsy1AwaHo4sKzai0AUAcCzdTPOy-MAz6FIGuK1lr_cD_Cvz-YP4XSOSQGjHzGbEHz4QU7PGezt4i2qbiblnWISkuj0JLtE5o/s1600/kepler04-3+%252B2034913+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPsqq3-g7Oo0K03rW7oozyTaKGoRrabKqeuXteIsy1AwaHo4sKzai0AUAcCzdTPOy-MAz6FIGuK1lr_cD_Cvz-YP4XSOSQGjHzGbEHz4QU7PGezt4i2qbiblnWISkuj0JLtE5o/s400/kepler04-3+%252B2034913+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540262896656481714" border="0" /></a><br />A drifting random walk with a -70.83 Hz / 255.7 seconds = +0.2770 Hz/sec drift rate.<br /><br /><br /><span style="font-size:180%;">+2035122 Hz</span><br />This signal looked like an upper sideband (USB) to a nearby carrier. Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmSsoIfIdqYl_FoudVJ2qJBKYJsY7ojSHrwyPX_6WuIjtJ0huXzeH2bDbWdpYQo-atE_fjbsYCfBLL-c8_e0SUE6vBa5NRR28BwDN8Z5yx0X1IarJgs35g66kiEdeBjH2PTkEt/s1600/kepler04-3+%252B2035122+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmSsoIfIdqYl_FoudVJ2qJBKYJsY7ojSHrwyPX_6WuIjtJ0huXzeH2bDbWdpYQo-atE_fjbsYCfBLL-c8_e0SUE6vBa5NRR28BwDN8Z5yx0X1IarJgs35g66kiEdeBjH2PTkEt/s400/kepler04-3+%252B2035122+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540221581765668850" border="0" /></a>A drifting random walk with a +2.21 Hz / 255.7 seconds = +0.00864 Hz/sec drift rate. Blip pulsing with a 5.7 second periodicity. Here is a zoomed out spectrogram that shows the relationship of the previously mentioned LSB-carrier-USB signals:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGI_w9o1VMfcHY5-nQnJ5e2GMgyH4DyUUXRmdAP2CjzUgGTJeNPhbQNBD1KqoqEYxvFwjv1D1WIYhaK-iWsmE5VPC6k1FEpiC0dZh1UeV9K_wfH23IVAhJoZLvshXDRoybLwph/s1600/kepler04-3+%252B2034+kHz+LSB-carrier-USB.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 221px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGI_w9o1VMfcHY5-nQnJ5e2GMgyH4DyUUXRmdAP2CjzUgGTJeNPhbQNBD1KqoqEYxvFwjv1D1WIYhaK-iWsmE5VPC6k1FEpiC0dZh1UeV9K_wfH23IVAhJoZLvshXDRoybLwph/s400/kepler04-3+%252B2034+kHz+LSB-carrier-USB.png" alt="" id="BLOGGER_PHOTO_ID_5540269451045668866" border="0" /></a><br />The "LSB", "carrier", and "USB" signals all looked to be related in the Average spectrum with ±200 Hz spacings but they have different drift rates and aren't sidebands at all. This shows the importance of different perspectives. What looks like something in one visualization might have different characteristics in another viewpoint.<br /><br /><br /><span style="font-size:180%;">+2036687 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIlk_M8A-0UZYvhqAYhhD3-XHO5iwYR0RJnWD37H5DHo4jXrL1VfLuzoVPaHzFUOqdL_gJ3TtBUUo6A4S-RWjzYXF_qzUWEMD8t26JiB8GauY9SRLBpBu0pwyQo-ZigvOzNbPK/s1600/kepler04-3+%252B2036687+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIlk_M8A-0UZYvhqAYhhD3-XHO5iwYR0RJnWD37H5DHo4jXrL1VfLuzoVPaHzFUOqdL_gJ3TtBUUo6A4S-RWjzYXF_qzUWEMD8t26JiB8GauY9SRLBpBu0pwyQo-ZigvOzNbPK/s400/kepler04-3+%252B2036687+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540278558877823938" border="0" /></a><br />A drifting random walk with a -37.89 Hz / 255.7 seconds = -0.1482 Hz/sec drift rate.<br /><br /><br /><span style="font-size:180%;">+2037910 Hz</span><br />Decimating by 4096. Note that the frequency axis has been changed to Hz=2X so the entire signal fits on the screen.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhM9lUfgAQNo4IM2QSFxg5UYHuOhKAkmM9obInOCb3Zs0ZtvImgqYnPATo_udzijPhj8vUCEUXWn5yn9sLhCBJ2Zj1N9b4j1AvAJCfZ0zRyO-4wBB5IQ_tnudVb293Lg5juHnJR/s1600/kepler04-3+%252B2037910+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhM9lUfgAQNo4IM2QSFxg5UYHuOhKAkmM9obInOCb3Zs0ZtvImgqYnPATo_udzijPhj8vUCEUXWn5yn9sLhCBJ2Zj1N9b4j1AvAJCfZ0zRyO-4wBB5IQ_tnudVb293Lg5juHnJR/s400/kepler04-3+%252B2037910+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540280851471024018" border="0" /></a><br />A drifting random walk with a -69.40 Hz / 255.7 seconds = -0.2714 Hz/sec drift rate. A weak 27 second periodicity similar to what was seen above at +2031500 Hz.<br /><br /><br /><span style="font-size:180%;">+2038261 Hz</span><br />Decimating by 4096. Note that frequency axis is set to Hz=2X.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJdxU0zUqrLr2iT72QcT_0Otev-0LpudXcDBeSBp0UuTsVwIWvKhon4Apt7ITJCyCTEVvQRcqulW4Q69x8Xj6Z2I8ix6QRgdYm0LaEeGcrP5hytOMJhwywFaQXdzEpd4yOBrCg/s1600/kepler04-3+%252B2038261+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJdxU0zUqrLr2iT72QcT_0Otev-0LpudXcDBeSBp0UuTsVwIWvKhon4Apt7ITJCyCTEVvQRcqulW4Q69x8Xj6Z2I8ix6QRgdYm0LaEeGcrP5hytOMJhwywFaQXdzEpd4yOBrCg/s400/kepler04-3+%252B2038261+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540286894260650226" border="0" /></a><br />Two trajectories with a split point at 100 seconds mark near the middle. The upper section has a -25.65 Hz / 155.7 seconds = -0.1647 Hz/sec drift rate. The lower section has a -13.15 Hz / 100 seconds = -0.1315 Hz/sec drift rate.<br /><br /><br /><span style="font-size:180%;">+2038767 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh603emWwAB7NErSLgVjQkVh7iykgeVQ_w-hOVm5dwlZ0yZN_ccPdOMFqosuLn5JRpbMQiptGHY6UZe6iwQ4HMGWIUZ6xoQepBkPL88GSIvAYXhRSYJtDv_MxEjPbK6wmfJ8x_E/s1600/kepler04-3+%252B2038767+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh603emWwAB7NErSLgVjQkVh7iykgeVQ_w-hOVm5dwlZ0yZN_ccPdOMFqosuLn5JRpbMQiptGHY6UZe6iwQ4HMGWIUZ6xoQepBkPL88GSIvAYXhRSYJtDv_MxEjPbK6wmfJ8x_E/s400/kepler04-3+%252B2038767+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540291164614606818" border="0" /></a><br />A drifting random walk with a -12.30 Hz / 255.7 seconds = -0.04810 Hz/sec drift rate.<br /><br /><br /><span style="font-size:180%;">+2038960 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJ3opz91DZ9T_Mh9PJ5AogDjcAXVGLQSz5I92JgX3AmhSRuHH7yGigvHhxxqoAOxmYj8Yxuto0q2nT8lF_GcHwaWL3UFuLHb3xYB_gAjIy69qvibcOzkDhwcoYIy289cbULh8J/s1600/kepler04-3+%252B2038960+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJ3opz91DZ9T_Mh9PJ5AogDjcAXVGLQSz5I92JgX3AmhSRuHH7yGigvHhxxqoAOxmYj8Yxuto0q2nT8lF_GcHwaWL3UFuLHb3xYB_gAjIy69qvibcOzkDhwcoYIy289cbULh8J/s400/kepler04-3+%252B2038960+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540292604263932402" border="0" /></a><br />A drifting and oscillating random walk with a -43.95 Hz / 255.7 seconds = -0.1719 Hz/sec drift rate. The drift motion looks like a full cycle of a sinusoid.<br /><br /><span style="font-size:180%;">+2040365 Hz</span><br />Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGczVf0MKdKqQt0uJWQw_RnYopIfNAqFVIjk4zOGhqqH4vT2ypKbYx6knOaERvJjVGdU5Gq289ZqjJoot_78rB1zG2EoqIM3n7lCyvuOvJW8_hwFNPIgNGXXb9CdPSOJ8927Aw/s1600/kepler04-3+%252B2040365+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGczVf0MKdKqQt0uJWQw_RnYopIfNAqFVIjk4zOGhqqH4vT2ypKbYx6knOaERvJjVGdU5Gq289ZqjJoot_78rB1zG2EoqIM3n7lCyvuOvJW8_hwFNPIgNGXXb9CdPSOJ8927Aw/s400/kepler04-3+%252B2040365+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540294379109975874" border="0" /></a><br />A drifting random walk with a +10.34 Hz / 255.7 seconds = +0.04044 Hz/sec drift rate.<br /><br /><br /><a name="+2044295_Hz"></a><br /><span class="Apple-style-span" style="font-size:180%;">+2044295 Hz</span><br />Hydrogen's left sideband. The distance from Hydrogen's center of mass is -483 kHz. Decimating by 4096.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKEcojYij48QBx3AI3S7jwX8n5-HAeIJnmn31TS66PoB-q32G5chsrxdocCpH2AoUdolw9IMEI8BVY7t2CszWtuMis62QWF2Oz1S25So_NbrLkGcDxHQBCjlaJbod0nnNnVGSv/s1600/kepler04-3+%2B2044267Hz+spectrogram.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKEcojYij48QBx3AI3S7jwX8n5-HAeIJnmn31TS66PoB-q32G5chsrxdocCpH2AoUdolw9IMEI8BVY7t2CszWtuMis62QWF2Oz1S25So_NbrLkGcDxHQBCjlaJbod0nnNnVGSv/s400/kepler04-3+%2B2044267Hz+spectrogram.png" alt="" id="BLOGGER_PHOTO_ID_5520570788487906514" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 368px;" border="0" /></a><br />A drifting random walk with a -43.10 Hz / 255.7 seconds = -0.1686 Hz/sec drift rate.<br /><br />What at first looked like a drifting random walk in fact has periodic structure. Pay attention to the short vertical discontinuous lines that all appear to have a duration of ~4.5 seconds. It looks binary and has FSK characteristics but I have never seen a modulation implementation like this. Using baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> shows how these vertical bars line up.<br /><br /></div><div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOtkYKn9MNXDOdROT4-dY6gKRrXlUMPHC1R08e1s6TobQqqn1dowqHp9dgQqvtDCv6Av-lCal78-n-pJ0qjV_OHknrLJVgfNFQBdDVF0TOcYtBd_YiDjkJ-apwRty7S7ln4CjX/s1600/kepler04-3+%2B2044267Hz+periodicity+bars.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOtkYKn9MNXDOdROT4-dY6gKRrXlUMPHC1R08e1s6TobQqqn1dowqHp9dgQqvtDCv6Av-lCal78-n-pJ0qjV_OHknrLJVgfNFQBdDVF0TOcYtBd_YiDjkJ-apwRty7S7ln4CjX/s400/kepler04-3+%2B2044267Hz+periodicity+bars.png" alt="" id="BLOGGER_PHOTO_ID_5521365531815946034" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 368px;" border="0" /></a></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"></span><div style="text-align: center;"><br /></div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"></span>The clocking appears to be very stable. The periodicity bars synced up all 21 vertical discontinuous lines for a 4.503 second duration for a 0.2221 baud rate. Coding the vertical discontinuous bars as the "1" symbol and slanting wiggling drift as the "0" symbol results in this demodulated string of 54 symbols:<br /><br /><span style="font-size:85%;"><span style="font-family:courier new;">10101011000001010100000001101100000110(1000010101101010<br /></span></span><br />The "(" symbol represents an error because the slope briefly reversed direction and became positive, hence its shape looks like a parenthesis. Statistically the "(" symbol most likely is a "1" symbol.<br /><br />Using a context-free grammar to break down the demodulated string yields:<br /><br /><span style="font-size:85%;"><span style="font-family:courier new;">3(10) 11 5(0) 3(10) 6(0) 11011 5(0) 110(1 4(0) 2(10) 110 2(10)<br /></span></span><br />Runs of "10" and "0" appear common, while "11" and/or " "11011" are less frequent and may be separators or sync codes.<br /><br />As previously mentioned this modulation scheme is unusual. One way of generating this signal would be to have a drifting tone that periodically stops drifting for 4.5 seconds and then restarts ("drift-n-drop"). [Update: Zooming in shows that the vertical drops are not exactly stationary.] To look at this from a different frame of reference let us correct the steep drift rate by rotating the image by about 40° in a graphics editor.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUOGUtjYRC5w3EG1L7Th7dFqW-0l5u2-7QTxeCN8rslE3QjdS1rUJK1tKBoJEWu2R5KTaoVhxSR66bxvJR_9fjjW_FfAPBaIvX6Sx5dfauOxbmK-AgZTHg53u6hT7MsXF-472S/s1600/drift_rotate7.jpg"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUOGUtjYRC5w3EG1L7Th7dFqW-0l5u2-7QTxeCN8rslE3QjdS1rUJK1tKBoJEWu2R5KTaoVhxSR66bxvJR_9fjjW_FfAPBaIvX6Sx5dfauOxbmK-AgZTHg53u6hT7MsXF-472S/s400/drift_rotate7.jpg" alt="" id="BLOGGER_PHOTO_ID_5520636840558248114" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 399px;" border="0" /></a></div><div><div style="text-align: center;"><br /></div><br />In this point of view the signal shape takes on a wandering zigzag shape that has a very sawtooth-like appearance. In this rotated view the binary transitions are more pronounced. Now this was a cute graphical demonstration of what we are going to do next in the audio DSP domain.</div><div style="text-align: left;"><br /></div><div>Now let us properly drift correct this modulated signal using baudline's many DSP manipulation features as building blocks. Multiple instances of baudline need to be connected together to form a multi-pass processing chain. This can be done by using the <a href="http://baudline.com/manual/options.html#stdin">-stdin</a> / <a href="http://baudline.com/manual/options.html#stdout">-stdout</a> command line options, <a href="http://baudline.com/manual/options.html#jack">JACK</a>, SoundFlower, or the digital loop mode of an Edirol UA-25 USB device. </div><div><br /></div><div><div>Here are the basic steps:</div><div><ol><li>Set the <a href="http://baudline.com/manual/tone_generator.html#tone_generator">Tone Generator</a> to output a sine wave that is FM modulated by the <b>ramp up</b> function.</li><li>Set the mix (x*y) operation in the <a href="http://baudline.com/manual/channel_mapping.html#channel_mapping">Channel Mapping</a> window.</li><li>In one baudline instance play the decimated drifting signal at half speed with the <a href="http://baudline.com/manual/play_deck.html#play_deck">Play Deck</a>, record this stream in a second instance of baudline. You now have the intermediary drift corrected mix spectrogram image shown below.</li><li>Begin analysis by playing this drift corrected mixed signal to another instance of baudline. Use the Play Deck's LPF and HPF controls to create a bandpass filter, or use baudline's decimating down mixer to filter out the carrier and lower sideband.</li></ol></div></div><div>Intermediary image of the drift corrected "mix" spectrogram is a visual description of the DSP processing involved:</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKTchxFZKnxnmkYF3EYwbP3SY2nEf0LN1RAjqHSTD0L4ZkAlqLE0YGVv5c39cLXqgDjD4Ibz2TNxY009-T9hTZONpniPNSYAo1gUm3dSienRmbTAET_eZ6S7k0wxoM2fJnilRz/s1600/mix+0...22000Hz+linear+ramp+up+0.055Hz.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKTchxFZKnxnmkYF3EYwbP3SY2nEf0LN1RAjqHSTD0L4ZkAlqLE0YGVv5c39cLXqgDjD4Ibz2TNxY009-T9hTZONpniPNSYAo1gUm3dSienRmbTAET_eZ6S7k0wxoM2fJnilRz/s400/mix+0...22000Hz+linear+ramp+up+0.055Hz.png" alt="" id="BLOGGER_PHOTO_ID_5526941878345742482" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 377px;" border="0" /></a></span></div><div>The purple ramp up FM modulated sine wave is mixed (x*y) with the original signal to create a folded lower sideband and a straightened upper sideband. The upper sideband is extracted by using LPF/HPF filters or the decimating down mixer as a bandpass filter. Note that the Play Deck's speed and shift sliders can be used to adjust the spectral resolution and position. The Play Deck tools can also be used to listen to this signal.</div><div><br /></div><div>Here is the extracted drift-corrected signal:</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZ0j39jRsCU87Kw1FCvWpcnEAGtnCsRROh-RcXTtfcbW8ybCYtxUylPsAZwotVjd__4_sWVA6jl2iZg83VRpZkesaBe87bkiWkiRKm1CeB9GX_PqHXcAxZNe-hPg7Ss1jQ0G7H/s1600/kepler04-3+linear+ramp+44100.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZ0j39jRsCU87Kw1FCvWpcnEAGtnCsRROh-RcXTtfcbW8ybCYtxUylPsAZwotVjd__4_sWVA6jl2iZg83VRpZkesaBe87bkiWkiRKm1CeB9GX_PqHXcAxZNe-hPg7Ss1jQ0G7H/s400/kepler04-3+linear+ramp+44100.png" alt="" id="BLOGGER_PHOTO_ID_5527213817399037122" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 377px;" border="0" /></a></span></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><br /></span></div><div>We now have a drift corrected version of this modulated signal. Note that the correct sample rate is actually 531.956 samples/second. I see some signal features that I missed during the first look. Let's zoom in and explore.</div><div><br /></div><div>Decimate by another factor of 32 for a 0.00818 Hz/bin resolution.</div><div><div style="text-align: left;"><span class="Apple-style-span"><br /></span></div><div style="text-align: left;"><span class="Apple-style-span"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXyoZCQ7ZOdw-ZBcWbwdEJJcQC46dyWyu9qSqvy2aek5XMzsFKWRYAH4xE8QctS5xFJWaZ_s69zJtTQIk9aY1V0ZPQMHAybyy__qhUURGllhLg0iO1zw2mwB5DjsWqWnxJNt9j/s1600/kepler04-3+linear+ramp+16.76.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXyoZCQ7ZOdw-ZBcWbwdEJJcQC46dyWyu9qSqvy2aek5XMzsFKWRYAH4xE8QctS5xFJWaZ_s69zJtTQIk9aY1V0ZPQMHAybyy__qhUURGllhLg0iO1zw2mwB5DjsWqWnxJNt9j/s400/kepler04-3+linear+ramp+16.76.png" alt="" id="BLOGGER_PHOTO_ID_5526978762560915346" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 377px;" border="0" /></a></span></span></div><div style="text-align: left;"><span class="Apple-style-span"><br /></span></div><div style="text-align: left;"><span class="Apple-style-span">This looks like a hybrid modulation of pulses on a zigzag with groupings of FSK. It is interesting that the frequency before each zig and zag is approximately the same after. It is as if the creating machinery after each zigzag wants to return to a moving centroid.</span></div><div style="text-align: left;"><span class="Apple-style-span"><br /></span></div><div style="text-align: left;"><span class="Apple-style-span">The periodicity bars will make this concept clearer.</span></div><div style="text-align: left;"><span class="Apple-style-span"><span class="Apple-style-span"><br /></span></span></div><div style="text-align: left;"><span class="Apple-style-span"><span class="Apple-style-span"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghkgfo_H55KDHKtX67RxA0x88CiUfyR0VhdcxqcYAkQNAazYRkhOKOtj_eG2DWTfdA6jBCq7rbk-XW3pAoi96H2shvDA9-lYszsIA_dqqXeP3bYU_iFVmUoz0kIgBzDPmVVxxo/s1600/kepler04-3+49.329s+periodicity+bars+16.552.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghkgfo_H55KDHKtX67RxA0x88CiUfyR0VhdcxqcYAkQNAazYRkhOKOtj_eG2DWTfdA6jBCq7rbk-XW3pAoi96H2shvDA9-lYszsIA_dqqXeP3bYU_iFVmUoz0kIgBzDPmVVxxo/s400/kepler04-3+49.329s+periodicity+bars+16.552.png" alt="" id="BLOGGER_PHOTO_ID_5529492225905029954" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 377px;" border="0" /></a></span></span></span></div><div><span class="Apple-style-span"><span class="Apple-style-span"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><br /></span></span></span></div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"></span><div><br /></div><div>A fairly stable clocking with a periodicity of 1 / 49.239 seconds = 0.020309 symbol rate. The pattern is 0+0-0+0. The 3 states suggest that the zigzag modulation could be some form of trinary (base-3). The lack of positive to negative transitions {+-, -+} suggest a differential coding scheme but unfortunately 6 1/2 symbols isn't enough information to infer details with any level of confidence.</div><div><br /></div><div>Now let's use the periodicity bars again to measure the clocking rate of the FSK symbols. A smaller 1024 point FFT size was used along with the <b>blip Fourier</b> transform in magnitude space of a bit more resolution.</div><div><br /></div><div style="text-align: center;"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnjttn540Josst-cFAUOywePdzyfPMASavkiyefIUKXygrEjas6blO_t_oKFYW5Cv1_sqAlvt0eFvKA_Hcqa5MGWDDAdecoiZsgxBTCV2jeYaTO79RCbEBWNUO9LPVQaHRaUKr/s1600/kepler04-3+4.911s+periodicity+bars+16.552.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnjttn540Josst-cFAUOywePdzyfPMASavkiyefIUKXygrEjas6blO_t_oKFYW5Cv1_sqAlvt0eFvKA_Hcqa5MGWDDAdecoiZsgxBTCV2jeYaTO79RCbEBWNUO9LPVQaHRaUKr/s320/kepler04-3+4.911s+periodicity+bars+16.552.png" alt="" id="BLOGGER_PHOTO_ID_5530984682494678082" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 176px; height: 320px;" border="0" /></a></span></div><div><br /></div><div>The straighter pulse sections ( for example the 175 second position) clock perfectly with a periodicity of 1 / 4.9112 seconds = 0.20362 symbol rate. The faster FSK sections are off in an unusual symbol-and-a-half way. I mean every other symbol is sliced perfectly in the middle. Let's try again and focus on the faster FSK sections.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_2Qik51GX5I7uXZ7BjxaTW0ZLhGCunFuoB4bdZHroMyClLbNfaS-4YMBcJthJg0o2ca2obc9YUk1YbgvXgUeqUnOHhyphenhyphenbCufMMpwpSgnLV6aH6A_2suQauY284uJAL1BbK55Rk/s1600/kepler04-3+3.288s+periodicity+bars+16.552.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_2Qik51GX5I7uXZ7BjxaTW0ZLhGCunFuoB4bdZHroMyClLbNfaS-4YMBcJthJg0o2ca2obc9YUk1YbgvXgUeqUnOHhyphenhyphenbCufMMpwpSgnLV6aH6A_2suQauY284uJAL1BbK55Rk/s320/kepler04-3+3.288s+periodicity+bars+16.552.png" alt="" id="BLOGGER_PHOTO_ID_5530988410737310818" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 176px; height: 320px;" border="0" /></a></span></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><br /></span></div><div>All of the faster FSK sections clock perfectly with a periodicity of 1 / 3.2884 seconds = 0.30410 baud rate but the slower pulsed sections are now sliced incorrectly. So we are in the unpleasant situation where both symbol rates slice different sections of the modulated signal perfectly but fail when applied to the signal as a whole. One way to explain this is that the signal is switching between two different symbol rates which is a very unusual thing to do. It would make demodulation much more difficult but it might be beneficial (speculatively) by adding a second embedded clock which could provide some added ISM distortion immunity. Another way of explaining the two symbol rates is that both are wrong and the correct answer is a faster rate that is a least common multiple (LCM) of the two. Let's zoom in and try again with something in the 0.6 symbols/second range.</div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCxBKtdydz-DYnsqZ17u3YaWDYwMVN0xEhMQ5KuJicIL-te9SKCeyRun3YxJur_7lEGlQ7ROd5zwk-z0qG7ccei9TmbVRJGr58k4mJCggHtJZfKjV-GIwTU5uhqmqVKZ19RQ4E/s1600/kepler04-3+1.646s+periodicity+bars+16.552.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCxBKtdydz-DYnsqZ17u3YaWDYwMVN0xEhMQ5KuJicIL-te9SKCeyRun3YxJur_7lEGlQ7ROd5zwk-z0qG7ccei9TmbVRJGr58k4mJCggHtJZfKjV-GIwTU5uhqmqVKZ19RQ4E/s320/kepler04-3+1.646s+periodicity+bars+16.552.png" alt="" id="BLOGGER_PHOTO_ID_5530988632764270274" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 176px; height: 320px;" border="0" /></a></span></div><div><span class="Apple-style-span"><br /></span></div><div>Eureka! We have perfect clocking with a periodicity of 1 / 1.6457 seconds = 0.60764 symbol rate. The result does look strange with the slower pulses being triple sampled and the faster FSK sections being double sampled. It seems like a waste and I doubt it is a result of the binary data sequence. It could be an error redundancy scheme but I'm not going to speculate. What is important is that this faster symbol rate solves the data periodicity clocking perfectly.</div><div><br /></div><div>The delta between mark and space frequencies is about 0.3 Hz. Using a bandwidth of twice the mark/space delta (Nyquist) the spectral efficiency is 0.30410 baud / 0.6 Hz = 0.507 (bit/s)/Hz. Using the same bandwidth rule, the spectral efficiency of the FSK signal in the original Kepler-4 analysis is 0.5061 baud / 2.4 Hz = 0.211 (bit/s)/Hz which is a little less than half of what is seen here. So roughly half the baud rate, a fourth the bandwidth, for about double the spectral efficiency. So it scaled in a squared sort of way.</div><div><br /></div><div>A good question is what are the FSK bits doing in the zigzag sections? Maybe isolated FSK sections aren't the correct way to interpret the data? It could be a trinary scheme were the motions are either a {-, 0, +} ∆f adjustment instead of mark/space hopping? This would correspond with the first zigzag trinary modulation we saw with the slow 0.02 symbol rate.</div><div><br /></div><div>Now we are going to investigate any possible phase modulations by using the <b>blip Fourier</b> transform set to phase space. The blip transform incorporates a blind phase locking algorithm that is ideal for this sort of work. The Play Deck's LPF/HPF controls were used to create a narrow bandpass filter. Decimation was set to 2 so that the down mixer could be used to adjust the frequency center. Note the 265 samples/second rate is 16X higher than the previous modulation analyses. Ignore the reddish orange colors and focus on the vertical blue band near the arrow at 61 Hz. The blue color fluctuations represent a change of phase.</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaU2CmhjYP9TEUYjHTgHgfD2Npn2vAuHsDP-cySEfvWYnv6xOIWUvPY9H_6SL6PUDLy6K9kcgHPRehhZ2PqUPTpYjoAscfYibhVgT_RorCj4dsfqGM04dPAck4HivvAJZX4j74/s1600/blip+phase.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaU2CmhjYP9TEUYjHTgHgfD2Npn2vAuHsDP-cySEfvWYnv6xOIWUvPY9H_6SL6PUDLy6K9kcgHPRehhZ2PqUPTpYjoAscfYibhVgT_RorCj4dsfqGM04dPAck4HivvAJZX4j74/s400/blip+phase.png" alt="" id="BLOGGER_PHOTO_ID_5528028203270472770" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 297px; height: 400px;" border="0" /></a></span></div><div>What we see here are 4 distinct phases (0°, 90°, 180°, 270°) that suggests a <a href="http://baudline.com/manual/glossary.html#QPSK">QPSK</a> modulation scheme. The blueish "cos full" color palette was used because it helped reduce the visual phase ambiguity. </div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><span class="Apple-style-span" style="color: rgb(0, 0, 0);"></span></span>Next let's use baudline's periodicity bars to explore the modulation clocking.</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPtqWtKFu7AWTbUIl8vDvxkL0o8szjlLH6Zi5FKy4Im6W0bnCX2fr4X6F0xUWO_uteceC5B6xxRbHm0jDacL_XsYB6XyvKc8aKv1en2l6dbwOEX7lWLCmdbw902O-NFcfRW9BB/s1600/blip+phase+periodicity%3D9.365Hz.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPtqWtKFu7AWTbUIl8vDvxkL0o8szjlLH6Zi5FKy4Im6W0bnCX2fr4X6F0xUWO_uteceC5B6xxRbHm0jDacL_XsYB6XyvKc8aKv1en2l6dbwOEX7lWLCmdbw902O-NFcfRW9BB/s400/blip+phase+periodicity%3D9.365Hz.png" alt="" id="BLOGGER_PHOTO_ID_5528028628819359442" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 295px; height: 400px;" border="0" /></a></span></div><div><br /></div><div>Perfect symbol placement with a very stable clocking periodicity of 1 / 0.10678 seconds = 9.3649 symbol rate. Here is a demodulation of the phase symbols with the codes dark to light ={ 0,1, 2, 3 }.</div><div><br /></div><div><span class="Apple-style-span"><span class="Apple-style-span" style="font-size:14px;"><span class="Apple-style-span" style="font-family:'courier new';">202222120301202112113021012213020203</span></span></span></div><div><br /></div><div>36 symbols with no consecutive runs of 0's or 3's. There is not enough data to make much of this and as always my thresholds could of been off so demodulation errors are a definite possibility. We see 4 phases but is this really QPSK? Let us take a look with the <a href="http://baudline.com/manual/waveform.html#waveform">Waveform</a> window. Here is a random segment from the data file:</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiERHNNMh_wWpEeEafBQAUI_takz11ZmtXehT4Ni5z8UwNdgTaSMmsjoYN0CazeA1mJWk5AvPoFnEAMPxqdHwdkWpXugC5SWEa_ZU_umePyfUsvJmvyKnwBjsBxmgA69GRKudLa/s1600/waveform+QAM.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiERHNNMh_wWpEeEafBQAUI_takz11ZmtXehT4Ni5z8UwNdgTaSMmsjoYN0CazeA1mJWk5AvPoFnEAMPxqdHwdkWpXugC5SWEa_ZU_umePyfUsvJmvyKnwBjsBxmgA69GRKudLa/s400/waveform+QAM.png" alt="" id="BLOGGER_PHOTO_ID_5528048071873968610" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 100px;" border="0" /></a></span></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><br /></span></div><div>The two interesting features are what looks to be wave packets and the two quantized amplitude levels. The two energy levels suggest that this modulation is Quadrature Amplitude Modulation (<a href="http://baudline.com/manual/glossary.html#QAM">QAM</a>). So what we thought was QPSK becomes 8-QAM which nobody uses since 8-PSK is more efficient. To get a slightly different perspective let us look at the same data segment we analyzed above for the phase spectrogram but this time we'll look with the blip Fourier transform in <b>magnitude</b> space.</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_QMrTVO9i-wZwAGsFHujc4a6I-q8H8Nzn9c9ECBNqjoxIIJenCBxvhv1yrWEHYvcF8x2jQXGPyzApjKNcEPqreCEyJYdJZm0R3EegUDt9QsG_iU43EJ_gf5kzfszz12NNufJc/s1600/blip+magnitude.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_QMrTVO9i-wZwAGsFHujc4a6I-q8H8Nzn9c9ECBNqjoxIIJenCBxvhv1yrWEHYvcF8x2jQXGPyzApjKNcEPqreCEyJYdJZm0R3EegUDt9QsG_iU43EJ_gf5kzfszz12NNufJc/s400/blip+magnitude.png" alt="" id="BLOGGER_PHOTO_ID_5528379155409422914" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 297px; height: 400px;" border="0" /></a></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_QMrTVO9i-wZwAGsFHujc4a6I-q8H8Nzn9c9ECBNqjoxIIJenCBxvhv1yrWEHYvcF8x2jQXGPyzApjKNcEPqreCEyJYdJZm0R3EegUDt9QsG_iU43EJ_gf5kzfszz12NNufJc/s1600/blip+magnitude.png"></a></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_QMrTVO9i-wZwAGsFHujc4a6I-q8H8Nzn9c9ECBNqjoxIIJenCBxvhv1yrWEHYvcF8x2jQXGPyzApjKNcEPqreCEyJYdJZm0R3EegUDt9QsG_iU43EJ_gf5kzfszz12NNufJc/s1600/blip+magnitude.png"></a><div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_QMrTVO9i-wZwAGsFHujc4a6I-q8H8Nzn9c9ECBNqjoxIIJenCBxvhv1yrWEHYvcF8x2jQXGPyzApjKNcEPqreCEyJYdJZm0R3EegUDt9QsG_iU43EJ_gf5kzfszz12NNufJc/s1600/blip+magnitude.png"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"></span></a><br /></div><div>This is left as an exercise for the reader. Aligning the periodicity bars up at the 9.365 symbol/sec rate again shows perfect modulation clocking but the symbols now take on 3 amplitude levels (bright red, medium red, and blue). So what looks like empty blue space between the red packets are in fact symbols. So what we previously thought was 8-QAM now has 4 distinct phase and 3 amplitudes. Here is a demodulation of the amplitude symbols with the codes high to low = { a, b, c }.</div><div><br /></div><div><span class="Apple-style-span" style=";font-family:'courier new';font-size:14px;" >aaaaaabbbbacbccbbbbbbaabbabbbbbbcbcc</span></div><div><span class="Apple-style-span"><span class="Apple-style-span" style="font-size:14px;"><br /></span></span></div><div>What stands out are the three independent runs of six consecutive symbols (a's and b's) and the two cbcc sequences. Placing the demodulated phases and amplitudes symbols next to each other gives us a QAM representation.</div><div><br /></div><div><div><span class="Apple-style-span" style=";font-family:'courier new';font-size:14px;" >202222120301202112113021012213020203</span></div></div><div><span class="Apple-style-span" style=";font-family:'courier new';font-size:14px;" ><span class="Apple-style-span" style=";font-family:Georgia,serif;font-size:16px;" ><div><span class="Apple-style-span" style=";font-family:'courier new';font-size:14px;" >aaaaaabbbbacbccbbbbbbaabbabbbbbbcbcc</span></div><div><span class="Apple-style-span" style=";font-family:'courier new';font-size:14px;" ><br /></span></div></span></span></div><div>The QAM phase/amplitude pairs should be read as columns { 2a, 0a, 2a, 2a, ...}. Assuming all the possible phase/amplitude combinations are populated we now have 12-QAM which not a common modulation scheme. This strange modulation could be due to analysis misinterpretation or it could be that the scheme is QAM-like but something slightly different. The only way to know for sure is to look at it in a constellation window. [Great, now I need to create another baudline tool!]</div><div><br /></div><div>As a sanity check of the blip phase locking algorithm here is the Waveform window with the periodicity bars set to a 9.365 symbol rate. The phase of the sinusoid does jump around in accordance to what the blip Fourier transform predicts. Cool.</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisXlGdD5eClIe-y8DuCHHzXmYQy0SCkvuR2ktmqU_Kt1pb004k2Bu90QruMf8YDmjPHEPtZQHcZm_KNRnzExjN2Vc7ey9JXuSHktOD6_qYk5QBiZUW2hcbhTjQ8R6oiR4047bR/s1600/waveform+QAM+periodicity.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisXlGdD5eClIe-y8DuCHHzXmYQy0SCkvuR2ktmqU_Kt1pb004k2Bu90QruMf8YDmjPHEPtZQHcZm_KNRnzExjN2Vc7ey9JXuSHktOD6_qYk5QBiZUW2hcbhTjQ8R6oiR4047bR/s400/waveform+QAM+periodicity.png" alt="" id="BLOGGER_PHOTO_ID_5528384811054154098" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 96px;" border="0" /></a></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisXlGdD5eClIe-y8DuCHHzXmYQy0SCkvuR2ktmqU_Kt1pb004k2Bu90QruMf8YDmjPHEPtZQHcZm_KNRnzExjN2Vc7ey9JXuSHktOD6_qYk5QBiZUW2hcbhTjQ8R6oiR4047bR/s1600/waveform+QAM+periodicity.png"></a></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisXlGdD5eClIe-y8DuCHHzXmYQy0SCkvuR2ktmqU_Kt1pb004k2Bu90QruMf8YDmjPHEPtZQHcZm_KNRnzExjN2Vc7ey9JXuSHktOD6_qYk5QBiZUW2hcbhTjQ8R6oiR4047bR/s1600/waveform+QAM+periodicity.png"></a><div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisXlGdD5eClIe-y8DuCHHzXmYQy0SCkvuR2ktmqU_Kt1pb004k2Bu90QruMf8YDmjPHEPtZQHcZm_KNRnzExjN2Vc7ey9JXuSHktOD6_qYk5QBiZUW2hcbhTjQ8R6oiR4047bR/s1600/waveform+QAM+periodicity.png"><span class="Apple-style-span" style="color: rgb(0, 0, 238);"></span></a><br /></div><div><br /></div><div>The 3 different modulation types (zigzag trinary, FSK pulsing, and QAM) layered on top of each other is extremely unusual. What is the significance of a <b>modulation</b> in a <b>modulation</b> in a <b>modulation</b>? That's modulation^3. I've never seen anything like this before. How could this be created? For what purpose?</div><div><br /></div><div>Here is a summary of the 3 modulation types and their respective symbol rates:</div><div><ul><li>zigzag trinary | Z = 0.020309 symbol rate (error ±0.00004)</li><li>FSK pulsing | F = 0.60764 symbol rate (error ±0.001)</li><li>12-QAM | Q = 9.3649 symbol rate (error ±0.01)</li></ul></div><div>Here are ratios comparing the symbol rates:</div><div><ul><li>F / Z = 0.60764 / 0.020309 = 29.920</li><li>Q / F = 9.3649 / 0.60764 = 15.412</li><li>Q / Z = 9.3649 / 0.020309 = 461.12</li></ul></div><div>The ratios round to the integers 30, 15, and 461 which factor to 2 * 3 * 5, 3 * 5, and prime respectively. While baudline's periodicity bars can make hyper-accurate measurements the margin of error is large enough that Q/Z could be 460. So any extra emphasis placed on a prime ratio value is likely unjustified. What is significant is how the symbol rate scales as the modulation complexity increases, first by 30 and then by about 15.</div><div><br /></div><div>Next let us look at the <b>Autocorrelation</b> transform which is a measure of self-similarity. A 4096 point FFT was used.</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4Q4QRe0iNsH4S_gGWEUbXjqqNdxEcvZXCaR0zVO2_0xYQJOkoN-Eh3z6GRUUZS5ebSHJhg0Fl3Rlsb2tWFsMChkHIqITN6ehgxceA1IZcgivmQNDE6F0VULFKmLdrv3RRWjKS/s1600/autocorrelation+FFT%3D4096.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4Q4QRe0iNsH4S_gGWEUbXjqqNdxEcvZXCaR0zVO2_0xYQJOkoN-Eh3z6GRUUZS5ebSHJhg0Fl3Rlsb2tWFsMChkHIqITN6ehgxceA1IZcgivmQNDE6F0VULFKmLdrv3RRWjKS/s400/autocorrelation+FFT%3D4096.png" alt="" id="BLOGGER_PHOTO_ID_5527291808734355986" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 376px;" border="0" /></a></span></div><div><br /></div><div>Autocorrelation with a 8192 point FFT and a slightly narrower Kaiser window.</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg6hHTHp0IQ8_UytxVvIuz_P3HmKU_iHzQzrovwtcPfBspy8Wlt0e-W7x-zNJrEdOpdGGvj-_-3Wbchk_TRa4NBOndYRMx6x3-Z7Gs2u7ZPDOuLY0fm4LqRxPpMOEA1zTHWb58/s1600/autocorrelation+FFT%3D8192.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg6hHTHp0IQ8_UytxVvIuz_P3HmKU_iHzQzrovwtcPfBspy8Wlt0e-W7x-zNJrEdOpdGGvj-_-3Wbchk_TRa4NBOndYRMx6x3-Z7Gs2u7ZPDOuLY0fm4LqRxPpMOEA1zTHWb58/s400/autocorrelation+FFT%3D8192.png" alt="" id="BLOGGER_PHOTO_ID_5527292760948161138" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 368px;" border="0" /></a></span></div><div><br /></div><div>The 8192 point Autocorrelation version is sharper while the 4096 point version looks rougher and more grainy which most likely is due to the decreased FFT gain. This tells us that the periodic signals at work here are fairly local in time. </div><div><br /></div><div>There is a lot of structure in both Autocorrelation spectrograms with the placement and spacing of the holes being the most intriguing feature. The holes I believe are a result of the hybrid FSK-pulse-like modulation. There are a couple groups of what could be 10101010... symbols near the top and middle. Near the bottom are two slightly offset groups of 100100100... symbols. Both repetitive patterns could be training or sync sequences. Many random holes are scattered about in the middle and they could represent the data payload. It is extremely difficult to extract any meaning from 50 bits (symbols?) so this is all speculation.</div><div><br /></div><div>An important observation is how similar the holes look like those seen in the original Kepler-4 Autocorrelation analysis. [More comparison and analysis is needed to determine if this similarity can be construed as matching modulation markers. I'm delving into forensic signal analysis here. The question I am asking is were both Kepler-4 modulated signals created by the same process or machine? (as in the same modem or the same RFI mechanism)]</div><div><br /><br /><span style="font-size:180%;">+2045991 Hz</span><br />Decimating by 4096. Note that frequency axis is set to Hz=2X so that the full drift is visible.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUjoUERgmIkgC233mGvqWaF79RingunjYnfgWJdY1lsiwb0PwwCSRV6tSyRWofCpFFuW_awWLmuOs26kefYfwoXNjG8FlctmrXdeOBFwT7_IDk_3uqwZS3k0BIx9y0jN8Trxb0/s1600/kepler04-3+%252B2045991+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUjoUERgmIkgC233mGvqWaF79RingunjYnfgWJdY1lsiwb0PwwCSRV6tSyRWofCpFFuW_awWLmuOs26kefYfwoXNjG8FlctmrXdeOBFwT7_IDk_3uqwZS3k0BIx9y0jN8Trxb0/s400/kepler04-3+%252B2045991+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5540298023783317602" border="0" /></a><br />A drifting random walk with a +85.29 Hz / 255.7 seconds = +0.3336 Hz/sec drift rate. The drift looks like it has some oscillations with 54 second period.<br /><br /><br /><span style="font-size:180%;">+2416146 Hz</span><br />Signal in Hydrogen. Decimating by 4096.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidqiFy590gTTOXFOvpo57WQuL2Tfgg3YC8urwzW9eAwO9C_JnFws329I8QnZ_oepSgNDsONAfoqtkWDjxZm6QLLZzR8NNkHob0S01b_TCeH4ZLgeP1eroDBhxVKHNRpihxC4qt/s1600/kepler04-3+%252B2416146+Hz.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidqiFy590gTTOXFOvpo57WQuL2Tfgg3YC8urwzW9eAwO9C_JnFws329I8QnZ_oepSgNDsONAfoqtkWDjxZm6QLLZzR8NNkHob0S01b_TCeH4ZLgeP1eroDBhxVKHNRpihxC4qt/s400/kepler04-3+%252B2416146+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5539960332934848066" border="0" /></a>Non-drifting wideband noise. The scattered high energy blips are about +10 dB above the noise floor.<br /><br /><br /><span style="font-size:180%;">+3008373 Hz</span><br /></div><div>Hydrogen's right sideband. The distance from Hydrogen's center of mass is +483 kHz. Decimating by 4096.<br /></div><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioKSRVnWw2U0w3UIohZazWRx_GoqC0TihFmYxxr7gt0Q5Wj2ImxQ3UxoueaSiJdm-2s0H2L2vn2Gmm5jR6zxMt41xmejO-mEuwL78KhEn6sBBCRT7Sg6H4d4DRgliqjnZAkQE1/s1600/kepler-04-3+%2B3008373Hz+spectrogram.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioKSRVnWw2U0w3UIohZazWRx_GoqC0TihFmYxxr7gt0Q5Wj2ImxQ3UxoueaSiJdm-2s0H2L2vn2Gmm5jR6zxMt41xmejO-mEuwL78KhEn6sBBCRT7Sg6H4d4DRgliqjnZAkQE1/s400/kepler-04-3+%2B3008373Hz+spectrogram.png" alt="" id="BLOGGER_PHOTO_ID_5520661562239669634" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 368px;" border="0" /></a><br />Drifting wideband noise with a +62.76 Hz / 255.7 seconds = +0.2454 Hz/sec drift rate. The banded noise has upper and lower segments with a scattering of several high energy blips (narrow in time and frequency).<br /><br /><br /><span style="font-size:180%;">Kepler04-4</span><br />Date: May-14-2010<br />Start time: <b>11:04</b><br />Freq: <b>1420.0</b> MHz<br />RA,Dec: 19.041021,50.135753<br /><br />The kepler04-4*.dat files are the second data set in this redux and they have a different base frequency and a slightly later start time. A Welch windowed 65536 point FFT for a 266.67 Hz/bin resolution was used to create the image below.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUNTFpeXRHLvCZ-V44zttD9VuZ2AsPKi9ZVFKRuo5NL8aVVvABP8Cp8j0Wv4AHj5Z98w4eldOnuHs23Nlr85IT6iXUSwO0Ujm6NtWz3Ap7XYDkAG26Xrf9Bb_HmCZwd0a0VRUM/s1600/kepler04-4+screen-capture.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUNTFpeXRHLvCZ-V44zttD9VuZ2AsPKi9ZVFKRuo5NL8aVVvABP8Cp8j0Wv4AHj5Z98w4eldOnuHs23Nlr85IT6iXUSwO0Ujm6NtWz3Ap7XYDkAG26Xrf9Bb_HmCZwd0a0VRUM/s400/kepler04-4+screen-capture.png" alt="" id="BLOGGER_PHOTO_ID_5521324317451909426" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 320px;" border="0" /></a></div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUNTFpeXRHLvCZ-V44zttD9VuZ2AsPKi9ZVFKRuo5NL8aVVvABP8Cp8j0Wv4AHj5Z98w4eldOnuHs23Nlr85IT6iXUSwO0Ujm6NtWz3Ap7XYDkAG26Xrf9Bb_HmCZwd0a0VRUM/s1600/kepler04-4+screen-capture.png"></a><div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUNTFpeXRHLvCZ-V44zttD9VuZ2AsPKi9ZVFKRuo5NL8aVVvABP8Cp8j0Wv4AHj5Z98w4eldOnuHs23Nlr85IT6iXUSwO0Ujm6NtWz3Ap7XYDkAG26Xrf9Bb_HmCZwd0a0VRUM/s1600/kepler04-4+screen-capture.png"></a><div style="text-align: center;"><br /></div><br />Targets:<br /><ul><li>+44234 Hz "left of Hydrogen"</li></ul>Many of the other signals are in the Kepler04-4 data set but only the +44234 Hz modulated candidate signal will be verified.<br /><br /><span style="font-size:180%;">+44234 Hz</span><br />This signal is -486 kHz left of Hydrogen's center of mass. Decimating by 4096.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgj3sLD8j5SKohxyOETRKnFbCZrRbvlqt77qfoj-FvzYqr_z7SebI4NApEwXIG8F-bNYeIpV36KlV5fFwADW2Tu1FgY2FBQktB1EitbvKfSZTdwSOLoZXEoIZerbHrLxpbJETRu/s1600/kepler-04-4+%2B44234Hz+spectrogram.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgj3sLD8j5SKohxyOETRKnFbCZrRbvlqt77qfoj-FvzYqr_z7SebI4NApEwXIG8F-bNYeIpV36KlV5fFwADW2Tu1FgY2FBQktB1EitbvKfSZTdwSOLoZXEoIZerbHrLxpbJETRu/s400/kepler-04-4+%2B44234Hz+spectrogram.png" alt="" id="BLOGGER_PHOTO_ID_5521277686088177570" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 368px;" border="0" /></a><br />A drifting random walk with a -39.26 Hz / 322.4 seconds = -0.1218 Hz/sec drift rate. Baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> again show a ~4.5 second periodicity.Here is the drift corrected spectrogram:<br /><br /></div><div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTTHB8gKRAlxhQh_GAP5pJRfTHMVcR2V5W6nqAr1p3bNXlqbvKNzib8ZM-V7cunAARfpTWRTHG4xQy9z6OoDLGAE3z0wPbP9gps2eZPUlQtcFtVwjIBlVYsR1HxMGSMD-qMbhW/s1600/kepler-04-4+periodicity+bars+51.353+Hz.png"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTTHB8gKRAlxhQh_GAP5pJRfTHMVcR2V5W6nqAr1p3bNXlqbvKNzib8ZM-V7cunAARfpTWRTHG4xQy9z6OoDLGAE3z0wPbP9gps2eZPUlQtcFtVwjIBlVYsR1HxMGSMD-qMbhW/s400/kepler-04-4+periodicity+bars+51.353+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5530963910957184882" style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 365px;" border="0" /></a></span></div><div><div style="text-align: center;"><span class="Apple-style-span"><br /></span></div><span class="Apple-style-span" style="color: rgb(0, 0, 238);"></span><div><br /></div>A very similar trinary/differential modulation shape. The periodicity bars measured a 51.353 second symbol rate which is close to the previously measured 49.239 periodicity. How does this compare to the modulated signal at +2044295 Hz seen in the first Kepler04-3 dataset? The drift rate, drifted starting frequency, top-layer modulation scheme and symbol rate all match so the signal in this dataset is a continuation of the first.</div><div><br /></div><div><br /><span class="Apple-style-span" style="font-size:x-large;">TBD<br /></span>This blog post is a work-in-progress. I might even add a movie for the zigzag modulated signal at +2044295 Hz. Check back soon.<br /><br /><br /><span style="font-size:180%;">Conclusion</span><br />A total of 21 signals were found in the Kelper04-3 data set. There was some wideband scatter noise and many drifting random walks. A few of the drifting random walks displayed interesting periodicities. The drifting +2044295 Hz signal exhibited unique modulation structure and was investigated in great detail.<br /><br />Let us compare that interesting FSK signal discovered in the <a href="http://baudline.blogspot.com/2010/04/setiquest-kepler-exo4-1420-mhz.html">original Kepler-04 analysis</a> done back in April to the unusual zigzag signal found today at <a href="http://baudline.blogspot.com/2010/09/setiquest-kepler-4b-redux.html#+2044295_Hz">+2044295 Hz</a>. The 2010-01-22-kepler-exo4 FSK signal was approximately -480 kHz left of Hydrogen, had a +0.0132 Hz/sec drift rate, and a 0.5064 baud rate. The 2010-05-14-kepler04-(3)(4) zigzag "drift-n-drop" signal is -483 kHz from Hydrogen's center of mass, has a -0.1686 Hz/sec drift rate, and 0.2221 baud rate. They have very different signal characteristics but they several important things in common:<br /><ul><li>same RA/Dec (celestial position)</li><li>distance left of Hydrogen (-480 kHz)</li><li>drifting in frequency</li><li>matching FSK modulation markers<br /></li><li>low modulated baud rate</li><li>similar Autocorrelation shapes<br /></li></ul>All of the above seems like too much of a coincidence to be random happenchance. Does this qualify as verification of the January Kepler-04 FSK signal? I think it does. Robackrman of the SETI Institute doesn't agree and thinks it is an "<a href="http://setiquest.org/forum/topic/discussion-roadmap-wiki#comment-1207">imprecise and wandering carrier</a>." Robackrman then uses a Pulsar B0809+74 data set recorded later that day as an OFF signal and <a href="http://setiquest.org/forum/topic/discussion-roadmap-wiki#comment-1284">shows the presence</a> of the drifting zigzag FSK signal. This suggests that the FSK signal is RFI. I am waiting for the SETI Institute to post this data set so I can confirm these findings.<br /><br />On 9-24-2010 the SETI Institute took a third look at Kepler-4b and this data has now been posted. I will be taking a look at it soon.<br /><br />A quick scan of <a href="http://baudline.blogspot.com/search/label/SETI">my old setiQuest reports</a> shows that the <a href="http://baudline.blogspot.com/2010/06/setiquest-pulsar-psr-b032954.html">pulsar PSR B0329+54 analysis</a> found an unusually modulated signal that was located -482 kHz left of Hydrogen. Hmmmm.</div><div><br /></div><div><br /></div><div><span class="Apple-style-span" style="font-size:x-large;">Links</span></div><div><ul><li><a href="http://setiquest.org/forum/topic/baudline-analysis-kepler-4b-redux">http://setiquest.org/forum/topic/baudline-analysis-kepler-4b-redux</a></li><li><a href="http://setiquest.org/forum/topic/discussion-roadmap-wiki#comment-1207">http://setiquest.org/forum/topic/discussion-roadmap-wiki#comment-1207</a></li></ul><br /></div><div><span class="Apple-style-span" style="font-size:85%;">Data licensed through </span><span style="font-size:85%;"><a href="http://seti.org/"><span class="Apple-style-span">SETI</span></a></span><span class="Apple-style-span" style="font-size:85%;">.</span></div><div><span class="Apple-style-span" style="font-size:85%;">Software licensed through </span><span style="font-size:85%;"><a href="http://sigblips.com/"><span class="Apple-style-span">SigBlips</span></a></span><span class="Apple-style-span" style="font-size:85%;">.</span></div></div>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com7tag:blogger.com,1999:blog-19780926.post-46364736076548000912010-09-22T10:37:00.000-07:002013-05-07T17:12:34.405-07:00setiQuest Deep Impact<div style="text-align: left;">
The <a href="http://www.baudline.com/">baudline signal analyzer</a> was used to analyze the <a href="http://setiquest.org/">setiQuest</a> Deep Impact satellite telemetry data file. Deep Impact was a 2005 NASA mission to crash a high velocity probe into the surface of comet 9P/Temple and make numerous measurements of the resulting explosion. That mission was successful and now the FlyBy section has been re-purposed to study other space phenomena. The Deep Impact satellite telemetry was captured by the ATA for this data file.</div>
<br />
The <a href="http://baudline.com/manual/glossary.html#quadrature">quadrature</a> data has a sample rate of 8738133.333 samples/second and since the meta data text file was missing the base frequency is unknown but believed to be in the X-band. The duration of the data file is 13 minutes and 23 seconds.<br />
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The following command line was used to stream the Deep Impact data files into baudline:<br />
<br />
<span style="font-size: 85%;"><span style="font-family: courier new;">cat 2010-01-22-deep-impact-* | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133 -fftsize 65536 -pause -utc 0</span></span><br />
<br />
A Welch windowed 65536 point <a href="http://baudline.com/manual/glossary.html#FFT">FFT</a> for a 266.67 Hz/bin resolution was used to create the image below.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPES7AX3Pvz8zNt1hEBJALY6TmkhMgMnoP-Q58tzEXVRSCE6BVGnOj3aFYhqwEUFJ37bX14GkTOCd5Ecsx7p_7lcDWp7_2QImElWkV94srWwanyKv5-Vmz7naMJMyzrzv7aDAK/s1600/full+screen+d1.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPES7AX3Pvz8zNt1hEBJALY6TmkhMgMnoP-Q58tzEXVRSCE6BVGnOj3aFYhqwEUFJ37bX14GkTOCd5Ecsx7p_7lcDWp7_2QImElWkV94srWwanyKv5-Vmz7naMJMyzrzv7aDAK/s400/full+screen+d1.png" id="BLOGGER_PHOTO_ID_5512480918585819122" style="cursor: pointer; display: block; height: 320px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The main features are the suppressed carrier (+797199 Hz), the lower and upper sidebands (+597205 Hz and +997194 Hz @ +3.5 dB), and their harmonics (±400000 Hz). It is interesting that the separation between the center carrier and its primary sidebands is ±200000 Hz which is half the spacing of the harmonics. The rest of the band looks clean.<br />
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Note that the <a href="http://baudline.com/manual/histogram.html#histogram">Histogram</a> display has a nice Gaussian shape with even/odd holes because of the signed 8-bit sampling.<br />
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<span class="Apple-style-span" style="font-size: x-large;">Zero Gaps</span><br />
The <a href="http://baudline.com/manual/waveform.html#waveform">Waveform</a> window shows a gap of zeroes:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtjJ6TUhU1oJjJfLyiVKxyvU4kkUXnUPjGXdVIA1oPZ-S-Le_HHx80kRZX9GmioHwD-wu-mRBHxYuaivYXt9hjNOuX71ULErM45eWXV57nPTdbk_nZnTcg0nD8PxGKi15zp-vj/s1600/waveform+gap.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtjJ6TUhU1oJjJfLyiVKxyvU4kkUXnUPjGXdVIA1oPZ-S-Le_HHx80kRZX9GmioHwD-wu-mRBHxYuaivYXt9hjNOuX71ULErM45eWXV57nPTdbk_nZnTcg0nD8PxGKi15zp-vj/s400/waveform+gap.png" id="BLOGGER_PHOTO_ID_5512493830532739106" style="cursor: pointer; display: block; height: 92px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The zero gaps happen 3 times in this data file at these time locations with these durations:<br />
<ul>
<li>2:54.9, ∆0.177 s</li>
<li>5:19.9, ∆0.115 s</li>
<li>5:45.0, ∆0.099 s</li>
</ul>
The zero gaps are believed to be caused by errors in the data collection process. They likely are dropped UDP packets where the collecting process did not get a full buffers worth of data so it filled in the missing gap with zeroes.<br />
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<br />
<span class="Apple-style-span" style="font-size: x-large;">+597205 Hz</span><br />
Decimating by 512 for an effective rate of 17066.666 sample/sec and down mixing into the main lower sideband at +597205 Hz.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-AjLROnC6fkJMxeUesmPXazth6G7AWsybMIX5e9iZoHfqHYNWwujJINQAAOZ_LEzt8OqF8uU6-WNBi4EAL_-xSYLmDGGWtZ4r6PFpf5Fq4kOgrZOnmXDqiO_kJj7z7IWeIo2l/s1600/full+screen+%2B597205+d512.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-AjLROnC6fkJMxeUesmPXazth6G7AWsybMIX5e9iZoHfqHYNWwujJINQAAOZ_LEzt8OqF8uU6-WNBi4EAL_-xSYLmDGGWtZ4r6PFpf5Fq4kOgrZOnmXDqiO_kJj7z7IWeIo2l/s400/full+screen+%2B597205+d512.png" id="BLOGGER_PHOTO_ID_5512816693431946018" style="cursor: pointer; display: block; height: 320px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The <a href="http://baudline.com/manual/average.html#average">Average</a> window shows the center subcarrier with some tight modulation products that will be explored in detail later. The center subcarrier has ±800 Hz lower/upper sidebands and their harmonics have spacings of ±1600 Hz. This is the same frequency spacing scheme seen with the main +797199 Hz carrier but the frequencies have been scaled by a factor of 200000 Hz / 800 Hz = 250. [What is the significance of 250?]<br />
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Also of interest is the spectrogram display which shows that all the sidebands and harmonics are stationary in frequency at this zoom level. The Histogram has a small spike at the zero value that is explained by the zero gaps mentioned above. Other than that it has a nice Gaussian shape.<br />
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Here is the Average window zoomed in with the Hz axis set to 4X.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2VIwLYaCkDxEXskNb9LW3ce5NRpNE2PuhjSWV3eS4A5xVtOpznC0gEuPtqPxu5jxff_yHxKZ9yz8p4JP2rtH-FnmSB8lx2ciNca23OdgyF6QIcHihH-kwvveF6f_rFEorbSbr/s1600/average+%2B597205+d512+Hz%3D4X.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2VIwLYaCkDxEXskNb9LW3ce5NRpNE2PuhjSWV3eS4A5xVtOpznC0gEuPtqPxu5jxff_yHxKZ9yz8p4JP2rtH-FnmSB8lx2ciNca23OdgyF6QIcHihH-kwvveF6f_rFEorbSbr/s400/average+%2B597205+d512+Hz%3D4X.png" id="BLOGGER_PHOTO_ID_5512831845614784642" style="cursor: pointer; display: block; height: 156px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The three main tones are separated by ±800 Hz. The harmonics next to the center subcarrier have a spacing of ±39.098 Hz. The left/right sidebands have harmonics with ±39.098 Hz spacings. They also have a second set of ±39.098 Hz harmonics that have an offset of 18.262 Hz that likely originated from the center subcarrier (800 - 18.262 / 39.098) = 19.994 which is very close to 20. This means that harmonics of the center subcarrier are interspersed with harmonics of the lower/upper sidebands and they all share a spacing of ±39.098 Hz.<br />
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The spectrogram below is the same view as above but the frequency axis has been zoomed in with a Hz=1X setting. The subcarrier and harmonics all have a slight curvature.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi49vVfCG19YNC5hR3EFUx6bNIlMiRWUO5DPUPKeS0eOUZyD3fzLw62cNAaM-7Rc7dXiDCyly0xftdx7t1hX0jgbzmPs15PH2vdSXB4H9YJmh8bBeR9FIVy1WXbYtI4BwVDY7Ul/s1600/spectrogram+%2B597205+Hz+d512+Hz%3D1X.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi49vVfCG19YNC5hR3EFUx6bNIlMiRWUO5DPUPKeS0eOUZyD3fzLw62cNAaM-7Rc7dXiDCyly0xftdx7t1hX0jgbzmPs15PH2vdSXB4H9YJmh8bBeR9FIVy1WXbYtI4BwVDY7Ul/s400/spectrogram+%2B597205+Hz+d512+Hz%3D1X.png" id="BLOGGER_PHOTO_ID_5512839962066300370" style="cursor: pointer; display: block; height: 224px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Let us take a closer look at the strongest tone in the center by using a decimation by 4096 factor for a 2133.3333 sample/second rate.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4mS34DBSNLZAhI80_szVQZHC-BikT-UH8bElaZ2szCJ_0XvQaiHA0gz4xZaW2Fpu5KEncz9t8TKXnriK20tlvySFaro-Dc2w4EMHNbE_84BWu1SfmDB-8RSHLWupz3oJYtDbh/s1600/spectrogram+%2B597205+Hz+d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4mS34DBSNLZAhI80_szVQZHC-BikT-UH8bElaZ2szCJ_0XvQaiHA0gz4xZaW2Fpu5KEncz9t8TKXnriK20tlvySFaro-Dc2w4EMHNbE_84BWu1SfmDB-8RSHLWupz3oJYtDbh/s400/spectrogram+%2B597205+Hz+d4096.png" id="BLOGGER_PHOTO_ID_5512773044370786946" style="cursor: pointer; display: block; height: 368px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This signal has a curved drift. The first half descends in frequency for a -3.06 Hz / 449 seconds = -0.00682 Hz/second drift rate. The second half ascends in frequency for a +2.08 Hz / 351 seconds = +0.00593 Hz/second drift rate. [Describe the possible motion that could cause this Doppler shape.]<br />
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<br />
<span class="Apple-style-span" style="font-size: x-large;">+797200 Hz</span><br />
Decimating by 512 for an effective rate of 17066.666 sample/sec and down mixing into the main suppressed carrier at +797200 Hz. Below is the Average display with a Hz=32X scaling.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwp-1AuDuvvVyNqefXJYKw6yTkpyM3-7Ph0D-UfG-YBMnLirWGlJTThq09xGIpuumwU9frKnMghZbE0EcGzw7ETC6JL0iVWOOtLKBMg3xw9LLTyXwW-u_1BVgNSZkOnq1ht8VD/s1600/average+%2B797200+Hz+d512.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwp-1AuDuvvVyNqefXJYKw6yTkpyM3-7Ph0D-UfG-YBMnLirWGlJTThq09xGIpuumwU9frKnMghZbE0EcGzw7ETC6JL0iVWOOtLKBMg3xw9LLTyXwW-u_1BVgNSZkOnq1ht8VD/s400/average+%2B797200+Hz+d512.png" id="BLOGGER_PHOTO_ID_5512848292740483826" style="cursor: pointer; display: block; height: 154px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The main center carrier has the same ±800 Hz lower/upper sidebands with ±1600 Hz harmonics that was seen above at +597205 Hz. What is missing are all the ±39.1 Hz harmonics. The main center carrier is much cleaner.<br />
<br />
Below is the decimate by 4096 spectrogram view.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijc6lq_V0Gl7uJBebl4WVnVKuu_RL3lM-xbg4kZBNKXcd-V41LkzsD7FRzr2JG1Spk9L4lE4kWjPx-HCC7qrWrXVd4a7oTcd2nMWhOgZh-7nT1tcT3jEyS0mSBKLkJ1iVJfblI/s1600/spectrogram+%2B797200+Hz+d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijc6lq_V0Gl7uJBebl4WVnVKuu_RL3lM-xbg4kZBNKXcd-V41LkzsD7FRzr2JG1Spk9L4lE4kWjPx-HCC7qrWrXVd4a7oTcd2nMWhOgZh-7nT1tcT3jEyS0mSBKLkJ1iVJfblI/s400/spectrogram+%2B797200+Hz+d4096.png" id="BLOGGER_PHOTO_ID_5512847676052228834" style="cursor: pointer; display: block; height: 368px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
This spectrogram looks identical to the curved-drifting-random-walk seen above.<br />
<br />
<br />
<span class="Apple-style-span" style="font-size: x-large;">+997194 Hz</span><br />
This is the upper sideband. The modulation and harmonic structures look identical to analysis that was done for +597205 Hz (lower sideband). The data for the spectrogram below was decimated by 4096.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUIqW4UcNB4lGgR82FB9LpMg6YSvUATfGu-s2HRnkg7WKlC7Vl_ssEqKScZ6JLk8VW_mgSj_Gt4qkmGwJymlzDKhqjv6na6zU8ySVQlfu-H3vPhYUUVhi3175lHeGmnpbtdStr/s1600/spectrogram+%2B997194+Hz+d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUIqW4UcNB4lGgR82FB9LpMg6YSvUATfGu-s2HRnkg7WKlC7Vl_ssEqKScZ6JLk8VW_mgSj_Gt4qkmGwJymlzDKhqjv6na6zU8ySVQlfu-H3vPhYUUVhi3175lHeGmnpbtdStr/s400/spectrogram+%2B997194+Hz+d4096.png" id="BLOGGER_PHOTO_ID_5512741725226773746" style="cursor: pointer; display: block; height: 368px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This signal looks identical to the ones shown above at different frequencies. The same drift shape is not a surprise but I would of expected the content to be frequency inverted.<br />
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<br />
<span class="Apple-style-span" style="font-size: x-large;">Modulation</span><br />
<div>
In this section the signal modulation of the +597205 Hz main tone of the lower sideband will be examined by down mixing and decimating by 524288. The effective sample rate is 33.3333 samples/sec.</div>
<div>
<br /></div>
<div>
Below is the Fourier spectrogram in magnitude space of an interesting section.</div>
<div>
<br /></div>
<div style="text-align: center;">
<span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; color: #0000ee;"><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline;"><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline;"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgv9W34iKuySuhkqBIihoA1wxDrJ5lNQ3Sb4fG9seKCOfiH_1fGsk7Nxi9NhiOVvvjAgU1k629FEIDIFUizHrfb9mfEPFJ4wNwQhrUCf9dCyodPYbzYQfy6xeGJSfSJ93Ezju5f/s400/blip+Fourier+magnitude+modulation.png" id="BLOGGER_PHOTO_ID_5519149827427850210" style="cursor: pointer; display: block; height: 368px; margin-bottom: 10px; margin-left: auto; margin-right: auto; margin-top: 0px; text-align: center; width: 400px;" /></span></span></span></div>
<div>
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The middle section looks a lot like ten symbols of <a href="http://baudline.com/manual/glossary.html#FSK">FSK</a> with an alternating (01)<sup>*</sup> pattern and a delta between mark/space of 0.49 Hz. The <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> measured a 1 /3.34 seconds = 0.299 baud rate. Below is the spectrogram of the same section of data but using the <b>blip Fourier</b> transform in phase space instead.</div>
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<span class="Apple-style-span"><span class="Apple-style-span"><br /></span></span></div>
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<span class="Apple-style-span"><span class="Apple-style-span"><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; color: #0000ee;"><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline;"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-ofNjHNUhg2IGLhUMa6cHz0nj92DVvj-6K0BCm8hsn6iT_IvNjnBt7ze_hTb2CPaTBeyFbLHRmx6pMjYdYY-D7rEY9E_aM35UExjZjseSPmsWdlnX3Yat0rTS_o6ospsC06wd/s400/blip+Fourier+phase+modulation.png" id="BLOGGER_PHOTO_ID_5519150279162280594" style="cursor: pointer; display: block; height: 368px; margin-bottom: 10px; margin-left: auto; margin-right: auto; margin-top: 0px; text-align: center; width: 400px;" /></span></span></span></span></div>
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Directly below the FSK section mentioned above looks to be a region of periodic phase changes. Two distinct phases are visible which suggests <a href="http://baudline.com/manual/glossary.html#BPSK">BPSK</a> modulation. Using the periodicity bars a 1 / 1.68 seconds = 0.595 baud rate was measured which is very close to double what was measured above.</div>
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Here is the blip Fourier phase spectrogram of a section a little farther down:</div>
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<div style="text-align: center;">
<span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; color: #0000ee;"><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline;"><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline;"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwayxEm0usEDNrq1QuzjHJWc85angAcGTjnkGkPMayDb8m3f58DfK2iLS42FH5TuBPwe134C5cXcNWdbu-tO7tNJpgLzBGYMfaf1_H2wiy4BR2pBz4831a_8YR_ic8DUx5a1to/s400/blip+Fourier+phase+modulation2.png" id="BLOGGER_PHOTO_ID_5519150818442211506" style="cursor: pointer; display: block; height: 368px; margin-bottom: 10px; margin-left: auto; margin-right: auto; margin-top: 0px; text-align: center; width: 400px;" /></span></span></span></div>
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<span class="Apple-style-span" style="-webkit-text-decorations-in-effect: underline; color: #0000ee;"><br /></span></div>
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Take note of the numerous phase changes in the center section. Four distinct phases are visible which suggests a <a href="http://baudline.com/manual/glossary.html#QPSK">QPSK</a>-like modulation scheme. Using the periodicity bars a 0.595 baud rate was measured again. </div>
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So we started with what looked like FSK and then jumped to BPSK and then to QPSK. Why? The clues are that the distance between FSK mark/space frequencies were very small and half the baud rate of the PSK measurements. Consecutive 00 and 11 symbols of BPSK can appear to look like very tight FSK. Then what appeared to be BPSK doubled its number of phases and became QPSK. Again QPSK can look like BPSK if only two symbols are being alternated. I believe the FSK / BPSK sections are actually QPSK of a sync header string such as (00001111)<sup>*</sup>(0011)<sup>*</sup> before the data sequence begins.</div>
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The only explanation I have for the extremely low baud rate is that the Deep Impact satellite is in a low power mode to conserve energy. A slower baud rate is also stronger and more tone-like which makes it easier for the Earth based telescopes to find it. This is only a guess since I wasn't able to find any information on-line about Deep Impacts modulation or telemetry schemes.</div>
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<span class="Apple-style-span" style="font-size: x-large;">Self Similarity</span><br />
Below is the <span style="font-weight: bold;">Autocorrelation</span> transform of the magnitude operation.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1zdPgjS76yHN_H-TRDyzs9z_3nmHyomcYGL59GXTjZl5ILeOLbiJCINCX-u6diqu4i1Z7gCLlt-n_JoNB4MeJ5Uq1_RG8NOqCT6bjca18RKLCRmYK9SkUFVg8nC1xag2i8ncX/s1600/autocorrelation+d1.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1zdPgjS76yHN_H-TRDyzs9z_3nmHyomcYGL59GXTjZl5ILeOLbiJCINCX-u6diqu4i1Z7gCLlt-n_JoNB4MeJ5Uq1_RG8NOqCT6bjca18RKLCRmYK9SkUFVg8nC1xag2i8ncX/s400/autocorrelation+d1.png" id="BLOGGER_PHOTO_ID_5512442909034827074" style="cursor: pointer; display: block; height: 352px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>The horizontal and vertical features were most unexpected. The 3 vertical lines are periodic with a 572 sample (65.4 microsecond) separation. It was a difficult measurement to perform but the <a href="http://baudline.com/manual/display.html#periodic_bars">periodic bars</a> proved to be very helpful in measuring a horizontal line periodicity of 1 / 0.01672 s = 59.82 Hz. So what is the significance of the 65.4 us and 59.82 Hz orthogonal lines?<br />
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Changing the point of view might help. Let us deconstruct the Autocorrelation transform down into its most basic primitive, the <span style="font-weight: bold;">sample Raster</span> transform. Below is a display of the sample Raster transform with its overlap width set to 572 samples in the <a href="http://baudline.com/manual/color_picker.html#scroll_control">Scroll Control</a> window.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaOWO_cOR5RIYQkraGULYugwbPlUJe6ycIeAi5h2LtDQQKIUrEnxBif17EWXICkqxvtlCf0r4ZChIiqXyDIGToQSBS7y44PcpHXnkbLTW5mbCVHp3_u75g4uz21jOD3JF0ZRMP/s1600/sample+rate+d1+ss%3D572.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaOWO_cOR5RIYQkraGULYugwbPlUJe6ycIeAi5h2LtDQQKIUrEnxBif17EWXICkqxvtlCf0r4ZChIiqXyDIGToQSBS7y44PcpHXnkbLTW5mbCVHp3_u75g4uz21jOD3JF0ZRMP/s400/sample+rate+d1+ss%3D572.png" id="BLOGGER_PHOTO_ID_5512416285753318546" style="cursor: pointer; display: block; height: 368px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>Three chirp-like <a href="http://baudline.blogspot.com/2006/05/vlf-whistler-echo-train.html">whistlers</a> are visible and they have a very LC discharge-like shape. There are thousands of these chirps and they are all slowly drifting to the left in time which signifies that the overlap width is fractional and not an exact integer. Assuming that this phenomena is in fact stationary a rough measure of the error is 13 / (145926.8 / 572) = 0.051 samples for a corrected overlap width of 571.949 samples (1 / 65.4469 us = 15279.6 Hz).</div>
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The <a href="http://baudline.com/manual/display.html#periodic_bars">periodic bars</a> measured the chirp-to-chirp periodicity to be 0.01670 seconds which translates to a 59.88 Hz frequency which is suspiciously close to 60 Hz.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPIK_S89dNtrTTOShVC-Djp180UgZbbflFdFxMasHeu0_YaOqwhjZqhgo-YRw107Q0oYMI-5SjBkZFg6jH6Urg4IC0xndpV4q_QQsEUDpLU1abgPJdzlyd897dS5PwbpIYXO_O/s1600/polka_dotted_elephant.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPIK_S89dNtrTTOShVC-Djp180UgZbbflFdFxMasHeu0_YaOqwhjZqhgo-YRw107Q0oYMI-5SjBkZFg6jH6Urg4IC0xndpV4q_QQsEUDpLU1abgPJdzlyd897dS5PwbpIYXO_O/s200/polka_dotted_elephant.jpg" id="BLOGGER_PHOTO_ID_5512455985682327634" style="cursor: pointer; float: right; height: 77px; margin: 0pt 0pt 10px 10px; width: 96px;" /></a>This temporally encoded chirp with a 15279.6 Hz line frequency and 59.88 Hz repeating periodicity is a surprising discovery that gets even stranger. Decimating by 2 and moving the down mixer frequency shows that this chirp signal is stationary. This is true all the way down to a decimation factor of 256 at which point the signal disappears. This means that this chirp signal passes through a tuner filter mostly unharmed. Note that this is the same "quadrature magnitude elephant" phenomena that was first seen in the <a href="http://baudline.blogspot.com/2010/05/setiquest-exoplanet-060.html">Exoplanet 060</a> analysis report but the quadrature magnitude operation isn't required to see this particular LC chirp. Another difference is that the Exo 060 sighting focused on 1/3 Fs harmonics and different 25600 Hz subharmonics but 60 Hz was present there too.<br />
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Something interesting happens as you continue to decimate down while tuning into one of the sidebands. Here is the Autocorrelation transform when decimating by 4096 and down mixed to the +997 kHz upper side band.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih9FopHjNZxF7ruNLZPBD0TLVcc5P0VILvo8FGl-juqUDnkwtzu2hRDUGDx8gbSWXlid7idOYzu5yrbc7Xt_G9pbJjv2tIYSkb1l2-RfHQS1aKTyTUsH2NVvbz8w_sXPny3Qgg/s1600/autocorrelation+average+d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih9FopHjNZxF7ruNLZPBD0TLVcc5P0VILvo8FGl-juqUDnkwtzu2hRDUGDx8gbSWXlid7idOYzu5yrbc7Xt_G9pbJjv2tIYSkb1l2-RfHQS1aKTyTUsH2NVvbz8w_sXPny3Qgg/s400/autocorrelation+average+d4096.png" id="BLOGGER_PHOTO_ID_5512509933835657202" style="cursor: pointer; display: block; height: 146px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
This again was not what was expected. The peaks have a periodic spacing of 54.611 samples which works out to a repetition frequency of 1 / 25.534 ms = 39.064 Hz which was also seen above in the sideband harmonics. Changing our point of view helps show us what is going on. Here is a spectrogram of the <span style="font-weight: bold;">sample Raster</span> transform applied to the magnitude operation with an overlap width of 764 samples. Click on the image to see the fine details.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFkf1Mo-ZkTMpxZe38Ndb-mu998dGo5CQjZpT5e1HEnJhlnP-yq3QHJLQBf67PAJYGXHwclKg-awG-yuAvOk_qMwW81tygdkFt5krNWBSagngILl7PdXiAzC7SQOxZoDrbk8XR/s1600/mag+sample+raster+d4096+ss%3D764.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFkf1Mo-ZkTMpxZe38Ndb-mu998dGo5CQjZpT5e1HEnJhlnP-yq3QHJLQBf67PAJYGXHwclKg-awG-yuAvOk_qMwW81tygdkFt5krNWBSagngILl7PdXiAzC7SQOxZoDrbk8XR/s400/mag+sample+raster+d4096+ss%3D764.png" id="BLOGGER_PHOTO_ID_5512520329971101954" style="cursor: pointer; display: block; height: 368px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>The 14 vertical bars have a thickness of 8 samples (3.750 ms) and a very slight drift to the right with a slope of 9 / (612267 / 764) = 0.011 samples. This is the error term for a corrected overlap width of 764.011 samples (358.1 ms). The 3 longer horizontal black lines have time stamps that correspond to the 3 zero gaps mentioned above. Also of interest are the 40+ shorter horizontal lines that are bounded by the vertical bars. They are not zero gaps but have decreased amplitude. Their origin is unknown and their spacing appears random.<br />
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This vertical bar effect is not a function of the magnitude operation. Here is a decimation by 2048 view with the green and purple colors representing the I & Q channels. The changing wavy pattern is the main sideband frequency that is slowly drifting. So the vertical bars are stationary while the sideband signals drift.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEht2YgTwsiqUemTh4GjdWwUhxY_t8Pq0YTsMo4NTGUDY4Chpqlm8I8yR88l5EqBSa81KA8cH2pKNUG6jgzffPzT64dY-XDdBiCG94j9cYSvkN5OkdwWVFuywMuh1WX2JosogTSL/s1600/sample+raster+d2048+ss%3D764.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEht2YgTwsiqUemTh4GjdWwUhxY_t8Pq0YTsMo4NTGUDY4Chpqlm8I8yR88l5EqBSa81KA8cH2pKNUG6jgzffPzT64dY-XDdBiCG94j9cYSvkN5OkdwWVFuywMuh1WX2JosogTSL/s400/sample+raster+d2048+ss%3D764.png" id="BLOGGER_PHOTO_ID_5512486882971132034" style="cursor: pointer; display: block; height: 368px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Why the vertical bars? Is the 25.534 ms spacing significant? What do the 40+ bar-to-bar amplitude dropouts represent? I don't know these answers but some very complicated signal artifact-ing is taking place.<br />
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<span class="Apple-style-span" style="font-size: x-large;">Filter Extraction</span>The <b>impulse response</b> transform was used to compare the I and Q channels. To inverse the positive lag symmetry a Hilbert filter was applied to the I channel prior to calculating the impulse response. This effectively undoes quadrature. Note that the horizontal axis should be time lag (not Hz) and the vertical axis should be a linear scale (not dB).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKpb5O3bzLq7KN5K-8ItatGZo7hzivFYtS_1uUHyq9fMKFNC3ySWX2vpKOAUCDI-HWBufvG3UK-qdnOBLgg9z2cPPAUA1bZ-tbXYmd4ekRJlKXidPwR2QNmZX0KhSD-oOQDS0q/s1600/filter+extraction.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKpb5O3bzLq7KN5K-8ItatGZo7hzivFYtS_1uUHyq9fMKFNC3ySWX2vpKOAUCDI-HWBufvG3UK-qdnOBLgg9z2cPPAUA1bZ-tbXYmd4ekRJlKXidPwR2QNmZX0KhSD-oOQDS0q/s400/filter+extraction.png" id="BLOGGER_PHOTO_ID_5512856087175301858" style="cursor: pointer; display: block; height: 154px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXHdKOMvyd8gGY72q2ftbz9_-Oq9fDiADu7t6K6TSm_vHovF7AGLQ5gC8fGZy2Z7NjDHtqoyOviDDvvwlr7I9cShzxRxAmfqBfi59BPwSZEUS0oNjQUGZ1ta4e9dOfDyVoFBIB/s1600/filter+extraction.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><br /></a>Compared to all the other setiQuest <b>Filter Extractions</b> I've done the filter shape and the sharp notch at zero are upside down! Another unusual feature is the strong periodic ripple throughout the whole filter. This file had strong carrier tones which is not a good stimulus source like noise is. So this strange periodic ripple could be due to the carrier tones or to a very broken quadrature filter which is possible since this data file is from January 2010.<br />
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<span class="Apple-style-span" style="font-size: x-large;">Conclusion</span><br />
The Deep Impact signal has a very rich self-similar harmonic structure at multiple levels of zoom. At the top level a slightly suppressed carrier has sidebands that have a spacing of ±200000 Hz with weaker ±400000 Hz harmonics. Zooming in on one of the sidebands reveals a sub-sideband spacing of ±800 Hz with weaker ±1600 Hz harmonics. What is the significance of 200000 Hz / 800 Hz = 250 ratio of the harmonics? Zooming in further shows 39.1 Hz harmonics. Is the rich harmonic structure due to Deep Impact having a non-linear amplifier for radio transmission which is common in deep space probes for power efficiency reasons or are the rich harmonics an ATA collection artifact?</div>
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Zooming into any of the strong sidebands or harmonics reveals a drifting signal that looks like a mixed FSK / PSK modulation scheme at a low 0.595 baud rate. I believe the FSK section is actually QPSK of a repetitive header sequence. Deep Impact had a downlink speed in the Mbps range so why do I measure such a very low baud rate? Is Deep Impact in a low power sleep mode?</div>
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The Autocorrelation transform found something unusual and very unexpected. Further investigation with the Sample Raster transform shows abundant whistler-like chirps with a ~60 Hz periodicity. Zooming in with decimation by 4096 shows an Autocorrelation periodicity of 39.1 Hz that the Sample Raster shows to be vertical bars with encapsulated dropouts. Note that the finest harmonics of the upper/lower sidebands had the same ∆39.1 Hz spacing. What is the significance of the bars, the dropouts, and the relationship to the sideband harmonics?</div>
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This Deep Impact data is an excellent example of what a SETI signal might look like. It is unknown which analysis components are caused by the satellite and which are artifacts of the collection process. This is an important distinction but it really doesn't matter for the purposes of this analysis report because the rich harmonic structure, modulation, and raster features all have an equally fascinating complexity.</div>
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<span class="Apple-style-span" style="font-size: x-large;">Links</span><br />
<ul>
<li><a href="http://setiquest.org/forum/topic/baudline-analysis-deep-impact">http://setiquest.org/forum/topic/baudline-analysis-deep-impact</a></li>
</ul>
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<span class="Apple-style-span" style="font-size: x-small;">Data licensed through </span><a href="http://seti.org/"><span class="Apple-style-span" style="font-size: x-small;">SETI</span></a><span class="Apple-style-span" style="font-size: x-small;">.</span></div>
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<span class="Apple-style-span" style="font-size: x-small;">Software licensed through </span><a href="http://sigblips.com/"><span class="Apple-style-span" style="font-size: x-small;">SigBlips</span></a><span class="Apple-style-span" style="font-size: x-small;">.</span></div>
baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-47840298601432770182010-08-31T17:27:00.000-07:002010-09-03T11:52:44.887-07:00blip BPSK demodulationThis post is going to demonstrate the demodulation of a <a href="http://baudline.com/manual/glossary.html#BPSK">BPSK</a> signal by a blind phase locking algorithm called the <span style="font-weight: bold;">blip Fourier</span> transform. Binary Phase Shift Keying (BPSK) is a simple modulation scheme that adjusts the phase of a sine wave carrier by 180° depending on bit values. In PSK modulation all the information is encoded in the phase of the signal unlike Frequency Shift Keying (FSK) which modulates the frequency. The phase tracking <span style="font-weight: bold;">blip Fourier</span> transform is a new feature in the recently released <a href="http://www.baudline.com/news.html#baudline_1.08">baudline 1.08</a> version and you can read more about it in the on-line manual section about <a href="http://baudline.com/manual/channel_mapping.html#transform">transforms</a>.<br /><br /><br /><span style="font-size:180%;">Setup</span><br /><ol><li>Record or load a BPSK modulated signal into baudline.</li><li> In the Input Channel Mapping window set the transform to <span style="font-weight: bold;">blip Fourier</span> and the space to <span style="font-weight: bold;">phase</span>.</li><li>Zoom the spectrogram timebase axis down to the bit level.</li><li>Set the Windowing to Gaussian and adjust the beta value to taste.</li><li>View, measure, explore, ...</li></ol><br /><br /><span style="font-size:180%;">blip Fourier phase</span><br />The spectrogram display of the blip Fourier transform in phase space.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoNwe0q8swbrd5gyjef6cmyH2-l1aslzOfHzQyBbdw555rXBFjj4cdh6xhI6ykwiD3JH6ZF0kmLmZsFf3EOof9utBdAj3piMPwTIcfTwFbbZKkbWVo1FtdmSkk62kszuvlHSTK/s1600/blip+Fourier+phase.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 377px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoNwe0q8swbrd5gyjef6cmyH2-l1aslzOfHzQyBbdw555rXBFjj4cdh6xhI6ykwiD3JH6ZF0kmLmZsFf3EOof9utBdAj3piMPwTIcfTwFbbZKkbWVo1FtdmSkk62kszuvlHSTK/s400/blip+Fourier+phase.png" alt="" id="BLOGGER_PHOTO_ID_5511713274175478850" border="0" /></a>The carrier is at 1000 Hz and the modulated bits of the BPSK signal are clearly visible. The discontinuities represent 180° phase transitions and not absolute phase. Other interesting features are the fractal like structure that surrounds the carrier and the fabric of the noise floor to the right which is composed of interwoven phase worms. The elements of phase space are rich and quite literally complex in nature.<br /><br /><br /><span style="font-size:180%;">periodicity bars</span><br />Baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodic bars</a> are used to measure the periodicity of the phase transitions. Fine adjustment for exact alignment was accomplished with the up and down arrow keys. The bars aligned on the 180° phase transitions represent the modulated symbols. Click on the spectrogram image for a full size version that will show the periodicity bars in full detail.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWHBn_2-bBcpvfkUIcK4iibhCHgILgltypFEQa31rtEu_slgNlBdycdM-WJhZi9bA0s1DQAtmlSWfPvme4rG6grzGAoQaMA4bQbctR4mo0W3ROkxDxSpJBOZ5GZecuwNyiz1hI/s1600/blip+Fourier+periodicity+bars.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 376px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWHBn_2-bBcpvfkUIcK4iibhCHgILgltypFEQa31rtEu_slgNlBdycdM-WJhZi9bA0s1DQAtmlSWfPvme4rG6grzGAoQaMA4bQbctR4mo0W3ROkxDxSpJBOZ5GZecuwNyiz1hI/s400/blip+Fourier+periodicity+bars.png" alt="" id="BLOGGER_PHOTO_ID_5511722634685966610" border="0" /></a><br />Note the overlaid delta 0.016 second period value.<br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9F0ntNVST2kvVMZUBem0uhI_fCPZTBirNyB7H1a9zrcgp_WavKfD0UvOWtmyJcolRP7j12d-sSQyxbGT_yD0UpOzH0AdQdyM-6S86M_FA-No-KWGW2PF5fFsblxdV6Oz0wKX6/s1600/delta+selected_65.png"><img style="float: right; margin: 0pt 0pt 10px 10px; cursor: pointer; width: 161px; height: 53px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9F0ntNVST2kvVMZUBem0uhI_fCPZTBirNyB7H1a9zrcgp_WavKfD0UvOWtmyJcolRP7j12d-sSQyxbGT_yD0UpOzH0AdQdyM-6S86M_FA-No-KWGW2PF5fFsblxdV6Oz0wKX6/s400/delta+selected_65.png" alt="" id="BLOGGER_PHOTO_ID_5511982080692169570" border="0" /></a><span style="font-size:180%;">baud rate</span><br />The <a href="http://baudline.com/manual/measurements.html#delta_selected">delta selected</a> measurement window displays a higher accuracy period value and a convenience 1 / period = Hz calculation. In BPSK there are only two possible phases (0° and 180°) so the symbol rate equals the baud rate (1 bit/symbol) which the periodicity bars measured to be 63 Hz or 63 baud.<br /><br /><br /><span style="font-size:180%;">demodulated bits</span><br />Use the spectrogram's periodicity bars as a symbol clocking aid to manually demodulate the bit stream. Reading off the delta phase transitions corresponds to the bit string: 010100110010110100011010 or it's inversion 101011001101001011100101 since the true starting bit is unknown. The decoding of the meaning of these 24 bits is left as an exercise for the reader.<br /><br /><br /><span style="font-size:180%;">Conclusion</span><br />The remarkable revelation is that the blip Fourier transform has no a priori knowledge of the carrier frequency, baud rate, or even the PSK modulation scheme. It simply is blind phase locking and allowing a visual demodulation of the signal. Demodulating the actual bits from a BPSK signal is just a byproduct and a neat trick.<br /><br />Phase consists of half of the spectrum. Half. Previous analysis tools have discarded this phase information and focused solely on magnitude. Use the baudline signal analyzer and see the other half of what you've been missing.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com2tag:blogger.com,1999:blog-19780926.post-25657941263324407102010-07-15T19:38:00.000-07:002010-07-16T08:41:25.326-07:00blip Fourier previewThis post is a quick preview of the <span style="font-weight: bold;">blip Fourier </span>transform that is going to be in the upcoming 1.08 version of <a href="http://www.baudline.com/">baudline</a>. The new <span style="font-weight: bold;">blip Fourier</span> transform utilizes a blind phase locking algorithm to enhance the spectral display in both magnitude and phase spaces. This does two valuable things. First, the spectral resolution is enhanced in the magnitude space which is ideal for observing amplitude beating while deep zooming down to the sample level. Second, spinning phase in now locked which allows the phase space to contain visibly useful information.<br /><br /><br /><span style="font-size:180%;">Setup</span><br />For this demonstration two instances of baudline's <a href="http://baudline.com/manual/tone_generator.html#tone_generator">Tone Generators</a> were used to create a sine wave on the left channel and an <a href="http://baudline.com/manual/glossary.html#FM">FM</a> modulated triangle wave on the right channel. This multiple channel manipulation was done with CoreAudio but JACK could of accomplished the same test system.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4DIMUOtU8uagUYFJYRgCdTh_xQkePMdsEj0rnr3pByDGaKtTm0Cyyd7c0TwE7ww_z4YLwtpzHxDgcjx2ThHkycAtnlqIlDOr0GUaegLrUitwImtVb5RvG6NyMwN7tw2m5xARE/s1600/dual+tone+generators.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 372px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4DIMUOtU8uagUYFJYRgCdTh_xQkePMdsEj0rnr3pByDGaKtTm0Cyyd7c0TwE7ww_z4YLwtpzHxDgcjx2ThHkycAtnlqIlDOr0GUaegLrUitwImtVb5RvG6NyMwN7tw2m5xARE/s400/dual+tone+generators.png" alt="" id="BLOGGER_PHOTO_ID_5494296062514504194" border="0" /></a><br /><br />Next the <span style="font-weight: bold;">x * y</span> multiplication operation in the <a href="http://baudline.com/manual/channel_mapping.html#channel_mapping">Input Mapping</a> window was used to mix the left and right channels to create a single modulated channel.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNNsbYsDcjoiK7U987pnpQfft9Qt79VOh0V7tKH-zNCVY-2N_QdspO4YnigDJc4TQM6I8gWMVUPtA0lj4JuNZMzwPq2DDoS_E51pCADzkTSIAnqjOv6OOMC06uzVHuKNwZZhC_/s1600/input+mapping+x*y.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 63px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNNsbYsDcjoiK7U987pnpQfft9Qt79VOh0V7tKH-zNCVY-2N_QdspO4YnigDJc4TQM6I8gWMVUPtA0lj4JuNZMzwPq2DDoS_E51pCADzkTSIAnqjOv6OOMC06uzVHuKNwZZhC_/s400/input+mapping+x*y.png" alt="" id="BLOGGER_PHOTO_ID_5494297323284935106" border="0" /></a><br />The new synthesized channel was then run through the Waveform window, the Fourier transform, and both the magnitude and phase spaces of the <span style="font-weight: bold;">blip Fourier</span> transform.<br /><br /><br /><span style="font-size:180%;">Waveform</span><br />The time domain samples are displayed in the <a href="http://baudline.com/manual/waveform.html#waveform">Waveform</a> window. The FM sweep and the <a href="http://baudline.com/manual/glossary.html#AM">AM</a> beats are visible.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvSVG6M48GsV39c7iCtJ2toeTQ6N0os4ko4q3Z-b1tZNbsR0mdU4C7OgvrNIZ9ociQhxKjagDTCk46MroXTk8hune4gdJOg4LYcOaveG964DdkD3hFk7DgX4jZE5ga-SJdI6eN/s1600/waveform.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 114px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvSVG6M48GsV39c7iCtJ2toeTQ6N0os4ko4q3Z-b1tZNbsR0mdU4C7OgvrNIZ9ociQhxKjagDTCk46MroXTk8hune4gdJOg4LYcOaveG964DdkD3hFk7DgX4jZE5ga-SJdI6eN/s400/waveform.png" alt="" id="BLOGGER_PHOTO_ID_5494297867501569682" border="0" /></a><br /><br /><span style="font-size:180%;">Fourier magnitude</span><br />The frequency domain is displayed with the <a href="http://baudline.com/manual/display.html#main_window">Spectrogram</a> window using the standard Fourier transform. The main FM triangle shape is visible.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDZAGcHNpN_ewXaAxSMVAWxwJHaryI4H_xCLWF5xe-uENhFiceJOhaIn6IuSABOcz_V8ZH__W8ZNhdgqPA0HyFMGf1BqC_A4jH2BMt4ZaAd96Rlubt2XOgvqQfMWasC4qs9XJX/s1600/Fourier+magnitude.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDZAGcHNpN_ewXaAxSMVAWxwJHaryI4H_xCLWF5xe-uENhFiceJOhaIn6IuSABOcz_V8ZH__W8ZNhdgqPA0HyFMGf1BqC_A4jH2BMt4ZaAd96Rlubt2XOgvqQfMWasC4qs9XJX/s400/Fourier+magnitude.png" alt="" id="BLOGGER_PHOTO_ID_5494300623638403378" border="0" /></a><br />Note that the timebase is 1/64X so this is fairly deep zoom with each spectral slice representing less than 3 samples.<br /><br /><br /><span style="font-size:180%;">blip Fourier magnitude</span><br />The same spectrogram display and magnitude space as above but with the <span style="font-weight: bold;">blip Fourier</span> transform. Note the sharper edges, grid on the FM triangle, and the enhanced detail in the noise floor.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVPiQGge4wKW0bDsGBJqc0gJd5WCNpoaM9PKz1FbCaTUIRKVHDyd3NqXhLwl06_dfCpYCo3TascS8BfnJv2wjwUoNTdn9kB-W56OwHHfHikp_7JYLeesvzaoJFW0sU65OIfaJz/s1600/blip+Fourier+magnitude.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVPiQGge4wKW0bDsGBJqc0gJd5WCNpoaM9PKz1FbCaTUIRKVHDyd3NqXhLwl06_dfCpYCo3TascS8BfnJv2wjwUoNTdn9kB-W56OwHHfHikp_7JYLeesvzaoJFW0sU65OIfaJz/s400/blip+Fourier+magnitude.png" alt="" id="BLOGGER_PHOTO_ID_5494302002836884562" border="0" /></a><br />The grid pattern is not a DSP artifact but in fact amplitude beats which are a unique feature of the signal.<br /><br /><br /><span style="font-size:180%;">blip Fourier phase</span><br />This is the same spectrogram display of the <span style="font-weight: bold;">blip Fourier</span> transform as above but of the phase space. This means that the spectrogram's color axis and the spectrum's vertical axis are not dB magnitude but instead represent phase in radians (<span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±pi)</span></span>. The main signal features are the same but the blind phase locking creates interesting patterns that show how the phase is changing.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKIQlTYHSG_y3Zs_XnURLyHnzMBkynfXrzBx1S4j0xLPDD8zs_TjRcgcvrDOR-Zl-PgoYg6YL625aR8YAqTC5dBb1txKNyIEcHTqw1MAdds97Iory8OAxbxCn7Z_Gg_BSwpmS-/s1600/blip+Fourier+phase.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKIQlTYHSG_y3Zs_XnURLyHnzMBkynfXrzBx1S4j0xLPDD8zs_TjRcgcvrDOR-Zl-PgoYg6YL625aR8YAqTC5dBb1txKNyIEcHTqw1MAdds97Iory8OAxbxCn7Z_Gg_BSwpmS-/s400/blip+Fourier+phase.png" alt="" id="BLOGGER_PHOTO_ID_5494303840245460242" border="0" /></a><br />The diamond/triangular shaped blocks are not beats in this view space but phase modulation (<a href="http://baudline.com/manual/glossary.html#PM">PM</a>) created by the x*y operation. The second harmonic of the FM triangle shape has a similar phase structure. Beneath that are folded aliasing and other distortion products. It appears that the fabric of phase space is a layered summation of signals with the most prominent on top. The zebra-like ripples around the main signal elements have a rich complexity and will be studied further in a future blog post.<br /><br /><br /><span style="font-size:180%;">Conclusion</span><br />The <span style="font-weight: bold;">blip Fourier</span> transform is an enhanced view into the frequency domain that has many powerful uses. The phase and fine sample details of signals can be explored and analyzed in ways previously not possible. As amazing as the blip transform's blind phase locking algorithm is, it is not without its faults since the process does create some additional distortion which lowers the system <a href="http://baudline.com/manual/glossary.html#SNR">SNR</a>. So the <span style="font-weight: bold;">blip Fourier</span> transform is great for deep low-level zooming and fine structure examination but it is not suitable for weak signal work. It is not a replacement for the Fourier transform but instead an additional transform for the DSP toolbox.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-86587196356396893402010-06-16T13:07:00.000-07:002010-06-16T19:14:56.482-07:00setiQuest Crab PulsarThe <a href="http://www.baudline.com/">baudline signal analyzer</a> was used to analyze the <a href="http://setiquest.org/">setiQuest</a> Crab Pulsar (PSR B0531+21) data file. The <a href="http://baudline.com/manual/glossary.html#quadrature">quadrature</a> data has a sample rate of 8738133.333 samples/second and a base frequency of 1420.0 MHz. The 9.77 GB of data is 9 minutes and 32.5 seconds in duration (572.5 seconds).<br /><br /><span style="font-size:100%;">The following command line was used to stream the Crab Pulsar data files into baudline:</span><br /><br /><span style="font-size:85%;"><span style="font-family:courier new;">cat 2010-03-26-crab-8bit-* | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133 -pause -utc 0</span></span><br /><br />A 65536 point <a href="http://baudline.com/manual/glossary.html#FFT">FFT</a> for a 266.67 Hz/bin resolution was used to create the image below.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9GXQ6xE6sjpTEVhLdmofC2SjK-eM5ERGG64w4Avhw_iaxr2apGS85ewb4lLGsAB0_UAFyo2aRO5HKd9pFYDGObU9UlmLAt9sgJXJo4TdYbzNU4-240gwzv5az_FXaSpu21cTw/s1600/crab+spectro+d1+a_dB%3D16X.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9GXQ6xE6sjpTEVhLdmofC2SjK-eM5ERGG64w4Avhw_iaxr2apGS85ewb4lLGsAB0_UAFyo2aRO5HKd9pFYDGObU9UlmLAt9sgJXJo4TdYbzNU4-240gwzv5az_FXaSpu21cTw/s400/crab+spectro+d1+a_dB%3D16X.png" alt="" id="BLOGGER_PHOTO_ID_5482731871184585634" border="0" /></a><br />Hydrogen is the hump in the center of the spectrum at +200 kHz. A weak tone on the right side of the <a href="http://baudline.com/manual/average.html#average">Average display</a> in the bottom of the filter roll-off will be investigated in more detail below. This small tone was measured with the <a href="http://baudline.com/manual/measurements.html#fundamental_Hz_dB_PSD">fundamental Hz</a> window to be at +4315732.753 Hz. Another feature of interest are the horizontal bands in the main spectrogram display. Using the <a href="http://baudline.com/manual/display.html#periodic_bars">periodic bars</a> these bands were measured to have a periodicity of 3.489 seconds.<br /><br />The <span style="font-weight: bold;">magnitude</span> time domain operation was selected in the input <a href="http://baudline.com/manual/channel_mapping.html#channel_mapping">Channel Mapping</a> window along with a prototype summing option in the <a href="http://baudline.com/manual/waveform.html#waveform">Waveform display</a> at a timebase of 65536X to create the image below.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj60_w4fKEYXzZYMqKWJTGd-HE4z9d1u5-54-1SWn1mi0hyphenhyphenv7a_634TlBovPX_hDU_UIaKCfT3Tq1xTsK8RgyZU2x5msMB-cO5OjioOAII6eC9K65wrRs92xJ5QTPNR1ZYiRF4J/s1600/crab+waveform+magnitude+d1+T%3D3.5s.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 86px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj60_w4fKEYXzZYMqKWJTGd-HE4z9d1u5-54-1SWn1mi0hyphenhyphenv7a_634TlBovPX_hDU_UIaKCfT3Tq1xTsK8RgyZU2x5msMB-cO5OjioOAII6eC9K65wrRs92xJ5QTPNR1ZYiRF4J/s400/crab+waveform+magnitude+d1+T%3D3.5s.png" alt="" id="BLOGGER_PHOTO_ID_5482736007448934098" border="0" /></a><br />This looks like a sine wave that has the top of it's positive cycle clipped. Using the periodic bars again, the periodicity was measured to be 3.5 seconds. Only two and half cycles were used here which is why the above spectrogram measurement has more accuracy.<br /><br />Here is the same Waveform display from a section farther into the data file.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMC543f32Bi2SS5vEdKXUTqJ10ANl83d2Q_WMO64wBKR31NRXX-359Rsx_9U3_qE0kvAZcXE3bzWNLMRwYltsxP6NV_HQ6xufDn68ACvyLBcTy3Oy5Gs-NeB5fXub9dvy8-xsQ/s1600/crab+waveform2+magnitude.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 86px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMC543f32Bi2SS5vEdKXUTqJ10ANl83d2Q_WMO64wBKR31NRXX-359Rsx_9U3_qE0kvAZcXE3bzWNLMRwYltsxP6NV_HQ6xufDn68ACvyLBcTy3Oy5Gs-NeB5fXub9dvy8-xsQ/s400/crab+waveform2+magnitude.png" alt="" id="BLOGGER_PHOTO_ID_5482749969714263058" border="0" /></a><br />The shape has changed from flat topped clipping to pointy peaks. A slightly more accurate periodicity was measured to be 3.458 seconds.<br /><br /><br /><span style="font-size:180%;">Hydrogen has Sidebands<br /></span>The peak in the center at +200 kHz is hydrogen and it has sidebands that have a delta of <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±</span></span>1455 kHz. The sample rate 8738133 / 1455000 Hz = 6.0056 which is very close to the whole number six is suspicious. Sidebands with the same delta Hz were also seen in the <a href="http://baudline.blogspot.com/2010/05/setiquest-exoplanet-060.html">Exoplanet 060</a> data analysis.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtPdxPuo_ts6nU1aGSsjnk9iH6cC6Xsx7VEBq1_uNE9yHrSQfp_XfiAGznWlCWTTr4Y3NA4fLVT0U7rMqPqsTpJVyvYjVDeYqXtyVhG3WCgAR9V6SC2hai3BU4TrmzCypwl2Iu/s1600/crab+average+d1+dB%3D64X.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 150px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtPdxPuo_ts6nU1aGSsjnk9iH6cC6Xsx7VEBq1_uNE9yHrSQfp_XfiAGznWlCWTTr4Y3NA4fLVT0U7rMqPqsTpJVyvYjVDeYqXtyVhG3WCgAR9V6SC2hai3BU4TrmzCypwl2Iu/s400/crab+average+d1+dB%3D64X.png" alt="" id="BLOGGER_PHOTO_ID_5482739525463712626" border="0" /></a><br /><br /><span style="font-size:180%;">Auto Drift</span><br />In the sidebands image above there is a small peak just to left of Hydrogen near 0 Hz. We will examine this region by zooming in with a decimation factor of 64 for a 4.167 Hz/bin resolution. Below is the Average spectrum of the standard Fourier transform (green) and a version with <a href="http://baudline.com/manual/process.html#auto_drift">Auto Drift</a> (purple) enabled.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvWP6CTWFFKNtF-UCKG8PjZWVK0_driNDUkt2GjEP4MX-hZvPlfEvX72f3QHkb0a8Tpgx6czgCOxboTCENabmz4XZLdZjSg_Sa4B5xsyu2o5fIiOTCblFUYaVWrBFddg3vFTW5/s1600/crab+d64+average+auto+drift.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 148px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvWP6CTWFFKNtF-UCKG8PjZWVK0_driNDUkt2GjEP4MX-hZvPlfEvX72f3QHkb0a8Tpgx6czgCOxboTCENabmz4XZLdZjSg_Sa4B5xsyu2o5fIiOTCblFUYaVWrBFddg3vFTW5/s400/crab+d64+average+auto+drift.png" alt="" id="BLOGGER_PHOTO_ID_5483138858380546130" border="0" /></a><br />Only two peaks are visible with the Fourier transform. When Auto Drift is enabled, two new peaks appear and the original two peaks become even stronger (+1.5 dB). These four peaks will be investigated in more detail below.<br /><br /><br /><span style="font-size:180%;">-1201 Hz<br /></span>Decimation by 4096 for a 0.0651 Hz/bin resolution. This drifting-random-walk signal has a -84.90 Hz / 572.5 seconds = -0.1483 Hz/sec drift rate. The auto drift algorithm was used in this spectrogram for about 1 dB more signal extraction power. Note that the horizontal zoom was set to Hz=2X so that the drifting signal would fit on the screen.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidPkyD9NQuxvWVhi0Op59lgdt4By_bPttJ4oxj853K7VkGs4Htgp-wHrQFQyK3ORtBc2NFxIXYJnA7iJ8msRWolCP1qAuNVv6IwuKq-zk7ZdLrGZyZzLRvROxq1PhIVbzqKbST/s1600/crab+-1201+Hz+%28auto+drift%29.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 368px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidPkyD9NQuxvWVhi0Op59lgdt4By_bPttJ4oxj853K7VkGs4Htgp-wHrQFQyK3ORtBc2NFxIXYJnA7iJ8msRWolCP1qAuNVv6IwuKq-zk7ZdLrGZyZzLRvROxq1PhIVbzqKbST/s400/crab+-1201+Hz+%28auto+drift%29.png" alt="" id="BLOGGER_PHOTO_ID_5483100725197925378" border="0" /></a><br /><br /><span style="font-size:180%;">+20173 Hz</span><br />Decimation by 4096 for a 0.0651 Hz/bin resolution. This drifting-random-walk signal has a -30.53 Hz / 572.5 seconds = -0.05333 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgT11jwcym1e4WHj4VDbo6Ycn_wG7yRH78FaKS0UkCs4SMASlTh1ncJ72m38FP1EQndcA77EHt3KE_NF8OUWqnrZyQ76fKI_TfVzothA6eoZP15yHnLWtnHxWlokD700L-ik3iC/s1600/crab+%2B20173+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 368px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgT11jwcym1e4WHj4VDbo6Ycn_wG7yRH78FaKS0UkCs4SMASlTh1ncJ72m38FP1EQndcA77EHt3KE_NF8OUWqnrZyQ76fKI_TfVzothA6eoZP15yHnLWtnHxWlokD700L-ik3iC/s400/crab+%2B20173+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5483010882218294402" border="0" /></a><br /><br /><span style="font-size:180%;">+49999 Hz</span><br />Decimation by 4096 for a 0.0651 Hz/bin resolution. This drifting-random-walk signal has a -85.16 Hz / 572.5 seconds = -0.1488 Hz/sec drift rate. The auto drift algorithm was used in this spectrogram for about 1 dB more signal extraction power. Note that the horizontal zoom was set to Hz=2X so that the drifting signal would fit on the screen.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaizn7xTSg_TS9C7DKR34XcMIvW1GZzvaeUXBm-7cDy51_RZg9JfwOUnN9r9RkwndiC50xZJLNGXhokZ1dXOM-IRs8BURjzjrrcMzs5PwNTF3azMja9iq97UI3HQeWJk4IZlIw/s1600/crab+%2B49999+Hz+%28auto+drift%29.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 368px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaizn7xTSg_TS9C7DKR34XcMIvW1GZzvaeUXBm-7cDy51_RZg9JfwOUnN9r9RkwndiC50xZJLNGXhokZ1dXOM-IRs8BURjzjrrcMzs5PwNTF3azMja9iq97UI3HQeWJk4IZlIw/s400/crab+%2B49999+Hz+%28auto+drift%29.png" alt="" id="BLOGGER_PHOTO_ID_5483109689945795122" border="0" /></a><br />This signal is an identical twin to the -1201 Hz signal. They are separated by 49999 - -1201 = 51200 Hz.<br /><br /><br /><span style="font-size:180%;">+71373 Hz<br /></span>Decimation by 4096 for a 0.0651 Hz/bin resolution. This drifting-random-walk signal has a -30.53 Hz / 572.5 seconds = -0.05333 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheNK6vIJVp7WOUJOFjptpdB7hZUpt9y1OsR0GZec_CbiA1loYthP7G5e6Pjm0PhU57g9aoD0axcEkwo91omfk-qxAOipITMV61czJdTlLqi1AWtfaFETO_gREZ45nYf44Z8YlS/s1600/crab+%2B71373+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 368px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheNK6vIJVp7WOUJOFjptpdB7hZUpt9y1OsR0GZec_CbiA1loYthP7G5e6Pjm0PhU57g9aoD0axcEkwo91omfk-qxAOipITMV61czJdTlLqi1AWtfaFETO_gREZ45nYf44Z8YlS/s400/crab+%2B71373+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5483019249579819202" border="0" /></a>This signal is an identical twin to the +20173 Hz signal. They are separated by 71373.1 - 20173.1 = 51200.0 Hz.<br /><br /><br /><span style="font-size:180%;">+4315733 Hz</span><br />Decimation by 4096 for a 0.0651 Hz/bin resolution. This signal in the roll-off filter is the same frequency that was also examined in the <a href="http://baudline.blogspot.com/2010/06/setiquest-pulsar-psr-b032954.html">PSR B0329+54</a> Side Skirting analysis section.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiinzWrQIVFlAntswvNQCNLzZ-TEo8BX6oqE35XLRv_JlmV9glPU7LFRMp3vGRr_41At3-P935D9F_A57xYUagVNuqhnB9vkY9X961nKpetUbeHiLoKvhOyhVAH_Ziy8NcT9Ypq/s1600/crab+average+%2B4315733+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 152px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiinzWrQIVFlAntswvNQCNLzZ-TEo8BX6oqE35XLRv_JlmV9glPU7LFRMp3vGRr_41At3-P935D9F_A57xYUagVNuqhnB9vkY9X961nKpetUbeHiLoKvhOyhVAH_Ziy8NcT9Ypq/s400/crab+average+%2B4315733+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5482768777008391234" border="0" /></a><br />The <a href="http://baudline.com/manual/measurements.html#fundamental_Hz_dB_PSD">fundamental Hz</a> window measured the tone to be at +4315733.218 Hz which is within 0.033 Hz of the value measured in the PSR B0329+54 report. The signal was weaker and no sidebands were seen this time but the amplitude does seem to be pulsing.<br /><br />The Waveform window with the prototype summing feature shows oscillations that were measured with the periodic bars to have a periodicity of roughly 3.5 seconds, the same as seen above.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr6Xle63fRX8oNMaK2MFv4MkmIlYJPRNWCZ4a0CX7ry7cGmsZYLwytlrtWqu1Rb_JyKDkPAazDS8hPM35oWECGbaNEigYQncvK0gR7TVJ8D6Hr2xGlb6XmIx8j2izVwGTseQov/s1600/crab+waveform+%2B4315733+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 116px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr6Xle63fRX8oNMaK2MFv4MkmIlYJPRNWCZ4a0CX7ry7cGmsZYLwytlrtWqu1Rb_JyKDkPAazDS8hPM35oWECGbaNEigYQncvK0gR7TVJ8D6Hr2xGlb6XmIx8j2izVwGTseQov/s400/crab+waveform+%2B4315733+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5482771745899126002" border="0" /></a><br />Decimating by 131072 for a 0.00203 Hz/bin resolution. The Average display below shows that the single tone has spread out to 5 closely spaced tones and 2 sidebands with deltas of <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±</span></span>0.28 Hz.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQAlCmwU-bQbY2i2XdyqGMiEaUza-rOyAj7jzrFW6HkLDq6ul5Ui1hyLGSxBPp3wJnSKmAp5OcTuR6R6W8FlS0G-ovQQiSbDw1dm8r2qlECf4FO5KhV2OkpLJvS640pyBs0hWb/s1600/crab+average+d4096*32+%2B4315733+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 153px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQAlCmwU-bQbY2i2XdyqGMiEaUza-rOyAj7jzrFW6HkLDq6ul5Ui1hyLGSxBPp3wJnSKmAp5OcTuR6R6W8FlS0G-ovQQiSbDw1dm8r2qlECf4FO5KhV2OkpLJvS640pyBs0hWb/s400/crab+average+d4096*32+%2B4315733+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5482783568636876802" border="0" /></a><br />This fractal-like behavior was also seen in the PSR B0329+54 analysis. Similar yet distinctly different.<br /><br />The <span style="font-weight: bold;">blip Fourier</span> transform will be used next to explore how this signal is behaving as a function of time. The blip focus parameter was set to 2. The first spectrogram image is magnitude space and second is phase space.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8DazN9pBY47M0rXc6t3DwakyzmCe1JOdN3v7cnSFoI-Fao3PgqX2dE9b2nOMkCunb6LueM7wHSytVFaulFfd6dKOpG5BdkAJ4B8hrl5LOe_CgLcaGebmIiYjPvCi6kVVL_qoZ/s1600/crab+d4096*512+blip+magnitude.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 311px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8DazN9pBY47M0rXc6t3DwakyzmCe1JOdN3v7cnSFoI-Fao3PgqX2dE9b2nOMkCunb6LueM7wHSytVFaulFfd6dKOpG5BdkAJ4B8hrl5LOe_CgLcaGebmIiYjPvCi6kVVL_qoZ/s400/crab+d4096*512+blip+magnitude.png" alt="" id="BLOGGER_PHOTO_ID_5482816356607268482" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4120UpoM9qUJSEA9CEHoR19C18YcTLibAyrHLmJPTWVgj8oASSYhI4jB4ftXH6ToYA-DQVDCq_pDCLkdhG5BnyPIbdkHv5zfelODwPs5K8mqKc1s3B6sixCkpeDE2c5F-6_yu/s1600/crab+d4096*512+blip+phase.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 311px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4120UpoM9qUJSEA9CEHoR19C18YcTLibAyrHLmJPTWVgj8oASSYhI4jB4ftXH6ToYA-DQVDCq_pDCLkdhG5BnyPIbdkHv5zfelODwPs5K8mqKc1s3B6sixCkpeDE2c5F-6_yu/s400/crab+d4096*512+blip+phase.png" alt="" id="BLOGGER_PHOTO_ID_5482816492671920034" border="0" /></a><br />This complex behavior was seen in the Exoplanet 060 analysis. Is this phenomena being generated by multiple closely spaced tones toggling on and off or is it the byproduct of beat frequencies?<br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEge7U8nQ6OEj8ptoioL6ewDHU2gT3abVoBziAmgnQ8Oa2w99JNCr6mfNxgANZRy5jAw9UbCOcTnwcSZKich7jSHuJZySDRG5BsEc0odbhsLBAZD4yc1AEeNbIe7P4LdyBizTvT2/s1600/polka_dotted_elephant.jpg"><img style="margin: 0pt 0pt 10px 10px; float: right; cursor: pointer; width: 101px; height: 81px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEge7U8nQ6OEj8ptoioL6ewDHU2gT3abVoBziAmgnQ8Oa2w99JNCr6mfNxgANZRy5jAw9UbCOcTnwcSZKich7jSHuJZySDRG5BsEc0odbhsLBAZD4yc1AEeNbIe7P4LdyBizTvT2/s200/polka_dotted_elephant.jpg" alt="" id="BLOGGER_PHOTO_ID_5482782483299136386" border="0" /></a><span style="font-size:180%;">Quadrature Magnitude<br /></span>Baudline's Input Mapping <a href="http://baudline.com/manual/channel_mapping.html#operation">time domain operation</a> was set to quadrature <span style="font-weight: bold;">magnitude</span> to see the Fourier power envelope. The large elephants at 1/3, 2/3, and 3/3 Nyquist were last seen in the <a href="http://baudline.blogspot.com/2010/05/setiquest-exoplanet-060.html">Exoplanet 060</a> data. This Average spectral plot was done with no decimation.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEik0kLSwhJ8bonRgps8DAF63vCl20JcAg7C2tdUydcp1Hfc8s-H0oX6MQ8IrS1aD3FpjPh2nKyHOsQZo6v_l_W8ZKU5VIaElDrFeEFh8dDSfGhWfC0OAOZFI4vyFzlGb7Q3yOq7/s1600/crab+average+elephants.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 150px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEik0kLSwhJ8bonRgps8DAF63vCl20JcAg7C2tdUydcp1Hfc8s-H0oX6MQ8IrS1aD3FpjPh2nKyHOsQZo6v_l_W8ZKU5VIaElDrFeEFh8dDSfGhWfC0OAOZFI4vyFzlGb7Q3yOq7/s400/crab+average+elephants.png" alt="" id="BLOGGER_PHOTO_ID_5482743400242857298" border="0" /></a><br />The strong tones at 1/3 and 2/3 have sidebands that are at <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±</span></span>25600, <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±</span></span>76800, and <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±</span></span>128000 Hz from the center carriers. Only half of the tone at 3/3 is visible but its lower sidebands match these delta progressions. Zooming in on the dB axis shows a lot of low level harmonic structure:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEip6EusWjM2iaaTrXgBQhkyVMlt1AdLb2S_BNSwJ8NF41j6bzZZxxG9kNMF_osXPfCxmEt5s6uDiLb-U_ZhZTsDWcZpxNhGBt_4O6BmzpxpOTPIvjZtXU4KYNMzPKS45huUQ2rC/s1600/crab+average+elephants+dB%3D96X.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 148px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEip6EusWjM2iaaTrXgBQhkyVMlt1AdLb2S_BNSwJ8NF41j6bzZZxxG9kNMF_osXPfCxmEt5s6uDiLb-U_ZhZTsDWcZpxNhGBt_4O6BmzpxpOTPIvjZtXU4KYNMzPKS45huUQ2rC/s400/crab+average+elephants+dB%3D96X.png" alt="" id="BLOGGER_PHOTO_ID_5483463255188680530" border="0" /></a><br />The majority of those harmonics are separated by 51200 Hz. Zooming in on the Hz axis and looking at the region of spectrum to the left of the 1/3 elephant:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPD3zXEaf1J0ffd4bH_k0kT1Cu926rY51KnG46qIdIsZLfWuXu4x7RG9eLLJ6cwRNKeQ6_fDEtP46iMl0lalk7ZvkmDLZSlL6RDrarGR6PkwisT7SUGG7iuRa2C94g2vCVow87/s1600/crab+average+elephants+Hz%3D8X+dB%3D96X.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 153px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPD3zXEaf1J0ffd4bH_k0kT1Cu926rY51KnG46qIdIsZLfWuXu4x7RG9eLLJ6cwRNKeQ6_fDEtP46iMl0lalk7ZvkmDLZSlL6RDrarGR6PkwisT7SUGG7iuRa2C94g2vCVow87/s400/crab+average+elephants+Hz%3D8X+dB%3D96X.png" alt="" id="BLOGGER_PHOTO_ID_5483464067195186242" border="0" /></a><br />Like as above, most of the spacing between tones is 51200 Hz. There are weak tones at 12800 and 25600 Hz. The 51200 Hz tone is fairly strong and a tone at 417333.7 Hz is even stronger. A number of weaker tones are scattered about with different spacings.<br /><br /><br /><span style="font-size:180%;">Filter Extraction<br /></span>The impulse response transform was used to compare the I and Q channels. To inverse the positive lag symmetry a Hilbert filter was applied to the I channel prior to calculating the impulse response. This effectively undoes quadrature. Note that the horizontal axis should be time lag (not Hz) and the vertical axis should be a linear scale (not dB).<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTdyXCJUOuumoXWBkXGPpLRMYFI-J0W2V6ptLuv86VAwVss0EGBmkuQCVfwZibsUeafjGrXmlfcmifKiIl0moatorRttSOQ04pM09DEo-Iaqm_PWOFZ3SZtXN7zynEwm2aplhC/s1600/crab+filter+extraction.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 150px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTdyXCJUOuumoXWBkXGPpLRMYFI-J0W2V6ptLuv86VAwVss0EGBmkuQCVfwZibsUeafjGrXmlfcmifKiIl0moatorRttSOQ04pM09DEo-Iaqm_PWOFZ3SZtXN7zynEwm2aplhC/s400/crab+filter+extraction.png" alt="" id="BLOGGER_PHOTO_ID_5482761814261574290" border="0" /></a><br />A sharp notch at time zero within a low pass filter shape. This is very similar to what was seen in the Exoplanet 060 analysis but the with the filter shape inverted.<br /><br /><br /><span style="font-size:180%;">Conclusion<br /></span>The Crab Pulsar (PSR B0531+21) has a published periodicity of about 33 milliseconds. I was unable to see any pulses of that periodicity using the same quadrature magnitude Waveform summing technique used in the PSR B0329+54 analysis.<br /><br />This data file contained a number of interesting features:<br /><ul><li>Unusually shaped amplitude modulation with a period of 3.489 seconds.</li><li>Sample rate divided by hydrogen sidebands <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">delta ±</span></span>1455 kHz = 6.00</li><li>Found two pairs of twin signals that are separated by 51200 Hz.</li><li>The 1/3, 2/3, 3/3 elephants are back and they have 25600 Hz sidebands.</li></ul>Some of these we've seen before and some are new.<br /><br /><br /><span style="font-size:180%;">Links</span><br /><ul><li><a href="http://setiquest.org/forum/topic/baudline-analysis-crab-pulsar">http://setiquest.org/forum/topic/baudline-analysis-crab-pulsar</a></li></ul>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com8tag:blogger.com,1999:blog-19780926.post-79326153420765197392010-06-01T19:02:00.000-07:002010-09-26T17:24:46.825-07:00setiQuest Pulsar PSR B0329+54The <a href="http://www.baudline.com/">baudline signal analyzer</a> was used to analyze the <a href="http://setiquest.org/">setiQuest</a> pulsar PSR B0329+54 data file. he following command line was used to stream the pulsar data file into baudline:<div><br /></div><div><span style="font-size:85%;"><span style="font-family:courier new;">cat 2010-05-07-psrb0329+54-8bit-*.dat | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133 -fftsize 65536 -pause -utc 0</span></span></div><div><br /></div><div>The <a href="http://baudline.com/manual/glossary.html#quadrature">quadrature</a> data has a sample rate of 8738133.333 samples/second and a base frequency of 1420.0 MHz. The roughly 9 GB of data is 8 minutes and 40 seconds in duration. <a href="http://baudline.com/manual/glossary.html#decimation">Decimation</a> by 4 was used with a 65536 point <a href="http://baudline.com/manual/glossary.html#FFT">FFT</a> for a 66.67 Hz/bin resolution to create the image below.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHhbGra1w2DlW0TA6AroefnYYCFN1_HKDX_2f63bGvK5d5Nil_qJk1KUEQNOqg4Kx4zJq6zfLMIey_J0sTRWwVaxcwko1lWFi0FWHYkIgyo1B1yu67cdtHOA4rWVU8oBRT003o/s1600/PSR+B0329%2B54+complex+Fourier.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHhbGra1w2DlW0TA6AroefnYYCFN1_HKDX_2f63bGvK5d5Nil_qJk1KUEQNOqg4Kx4zJq6zfLMIey_J0sTRWwVaxcwko1lWFi0FWHYkIgyo1B1yu67cdtHOA4rWVU8oBRT003o/s400/PSR+B0329%2B54+complex+Fourier.png" alt="" id="BLOGGER_PHOTO_ID_5475690950593265650" border="0" /></a><br />The 5 lobed shape of roughly 500 kHz bandwidth in the center is hydrogen. The shape of interstellar hydrogen is spread out due to Doppler shift because it is undergoing a number of different velocities along its path to Earth. The midpoint of each of the lobes was measured to be:<br /><ul><li>+376533 Hz</li><li>+424000 Hz</li><li>+451200 Hz</li><li>+527467 Hz</li><li>+732267 Hz</li></ul><br /><br /><span style="font-size:180%;">Hydrogen has Sidebands<br /></span>The strongest peak of hydrogen (+527 kHz) is in the center of the <a href="http://baudline.com/manual/average.html#average">Average</a> display below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMjMHMbdkE7xzvLpSOek72tBn4UMb_AulbyJ9Sy4-HLO-JzPiX9Osw-xYiEUPeUHWWTuizpgpKIEmp6LKCHnVmO9y8gkxIQIjsP7b6OmmNATytTHJb0tdocOkuIQ1uCj9x3eaL/s1600/PSR+B0329%2B54+average+sidebands.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 154px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMjMHMbdkE7xzvLpSOek72tBn4UMb_AulbyJ9Sy4-HLO-JzPiX9Osw-xYiEUPeUHWWTuizpgpKIEmp6LKCHnVmO9y8gkxIQIjsP7b6OmmNATytTHJb0tdocOkuIQ1uCj9x3eaL/s400/PSR+B0329%2B54+average+sidebands.png" alt="" id="BLOGGER_PHOTO_ID_5475694600921422146" border="0" /></a><br />It looks like the strongest peak of hydrogen is directly in between the sideband-like tones. Let us verify this with some measurements and calculations. Baudline's <a href="http://baudline.com/manual/measurements.html#primary">primary Hz</a> and <a href="http://baudline.com/manual/measurements.html#fundamental_Hz_dB_PSD">fundamental Hz</a> windows were used to perform some extremely accurate measurements.<br /><br />Features of interest:<br /><ul><li>44468.190 Hz (lower sideband tone)</li><li>527467 Hz (strongest peak of hydrogen) estimated error = <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±700 </span></span>Hz<br /></li><li>1008467.116 Hz (upper sideband tone)</li></ul>Some math:<br /><ul><li>(1008467.116 - 44468.190) / 2 = 481999.463 Hz (sideband delta)</li><li>(1008467.116 + 44468.190) / 2 = 526467.653 Hz (midpoint)</li><li>527467 - 526468 = 999 Hz (center offset)</li></ul> So the center offset between the sidebands' midpoint and the strongest peak of hydrogen is 999 Hz which is slightly more than the estimated error for this difficult measurement. That sideband delta Hz value looks very suspicious at being almost 482000 Hz. This number factors to 2^4 * 5^3 * 241 which doesn't seem to have any relationship to the base ATA's 2^20 *100 sample rate or its decimate by 12 rate. So maybe its value doesn't have any importance but the fact the sidebands are almost perfectly centered is important.<br /><br /><br /><span style="font-size:180%;">Exploring the Sidebands</span><br />Decimation by 256 for a 1.0417 Hz/bin resolution was used to create the lower sideband image below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHEyLkvPEmJYOeWf1wLE_08N4z02uy5-tlloiO-oEd4w2hv6SsSY9ze1MUaxLALy8sOuQ8NwZG7cvt6ZEggqeSF9uaYWcQZqJlqPdYVxjLQF43TzVvNXlyhJ5-fLcPFg0idhNa/s1600/PSR+B0329%2B54+lower+sideband+nursery.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHEyLkvPEmJYOeWf1wLE_08N4z02uy5-tlloiO-oEd4w2hv6SsSY9ze1MUaxLALy8sOuQ8NwZG7cvt6ZEggqeSF9uaYWcQZqJlqPdYVxjLQF43TzVvNXlyhJ5-fLcPFg0idhNa/s400/PSR+B0329%2B54+lower+sideband+nursery.png" alt="" id="BLOGGER_PHOTO_ID_5477954598520150402" border="0" /></a><br />Twelve narrowband signals are visible in this "signal nursery." Baudline's <a href="http://baudline.com/manual/process.html#auto_drift">Auto Drift</a> algorithm was used in both the Average and Spectrogram displays above. The shape and the height of the Auto Drift curve can give some insight into a signal's drifting characteristics. The green dots represent stationary signals while the purple dots drifting signals. Both types will be investigated in more detail below.<br /><br />I call the area just to the left of hydrogen a <span style="font-weight: bold;">signal nursery</span> because large numbers of interesting features have been found in this location. For example; the drifting FSK signal in the <a href="http://baudline.blogspot.com/2010/04/setiquest-kepler-exo4-1420-mhz.html">Kepler Exo-4</a> data and the 15 signals in the <a href="http://baudline.blogspot.com/2010/05/setiquest-exoplanet-060.html">Exoplanet 060</a> data. Why the concentration of signals to the left of the main feature? There is no logical reason why this location is special so it could be a clue to an error in the ATA's digital signal processing chain.<br /><br />We will now explore these green and purple dot signals of interest by using decimation of 4096 with a 65536 point FFT for a 0.0651 Hz/bin resolution.<br /><br /><br /><span style="font-size:180%;">+30628 Hz<br /></span>A drifting-random-walk with a +2.15 Hz / 520 seconds = +0.00413 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhe0zl5117NWIEngnO45_3c0rktKNEMxMqdT7rqUHOwTylc8FIp1HpHt9W_DNggP_H0ZmzD90kmn6yGVoKM1eb5QfPBCTiYfn026ATNdepsqj8IsWXerajVCfqfH9HnDTsjqh_q/s1600/PSR+B0329%2B54+%2B30628+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 376px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhe0zl5117NWIEngnO45_3c0rktKNEMxMqdT7rqUHOwTylc8FIp1HpHt9W_DNggP_H0ZmzD90kmn6yGVoKM1eb5QfPBCTiYfn026ATNdepsqj8IsWXerajVCfqfH9HnDTsjqh_q/s400/PSR+B0329%2B54+%2B30628+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5477927433768942754" border="0" /></a><br /><span style="font-size:180%;">+31553 Hz<br /></span>A drifting-random-walk that has a large negative curvature with a -1.63 Hz / 520 seconds = -0.0313 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXsSFCZ21pSq_ow-JvVb6u4yA2adADdqku3r4qkNUxWAT-XSNaZAoYy0GKP7Nf-uSIdvHGkzmNjudkLQmLwf-rtmSOfNjw2_RhTp6mhCvaI3SLDKNzQss3Ojr6-s_vq9EwGyWs/s1600/PSR+B0329%2B54+%2B31533+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 376px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXsSFCZ21pSq_ow-JvVb6u4yA2adADdqku3r4qkNUxWAT-XSNaZAoYy0GKP7Nf-uSIdvHGkzmNjudkLQmLwf-rtmSOfNjw2_RhTp6mhCvaI3SLDKNzQss3Ojr6-s_vq9EwGyWs/s400/PSR+B0329%2B54+%2B31533+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5477929611008110418" border="0" /></a><br /><br /><span style="font-size:180%;">+32971 Hz<br /></span>A fast drifting-random-walk with a -106.12 Hz / 520 seconds = -0.2041 Hz/sec drift rate. Note that the horizontal zoom was set to Hz=2X so the signal drift is comparatively twice as wide as it appears in the spectrogram below.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSd9K4YZVed3gOmhn3Gy8oswfOxYfUPG0pae8BPCJr16-btXbgqkVwNPEQnfVGnJUjzr7_C9UuHj2CjQ_VJzSzpDi3Ov8iaEHmPMK7ew5EoyLE_6KsyGofPLuNHN80apWMqx6_/s1600/PSR+B0329%2B54+%2B32971+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 376px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSd9K4YZVed3gOmhn3Gy8oswfOxYfUPG0pae8BPCJr16-btXbgqkVwNPEQnfVGnJUjzr7_C9UuHj2CjQ_VJzSzpDi3Ov8iaEHmPMK7ew5EoyLE_6KsyGofPLuNHN80apWMqx6_/s400/PSR+B0329%2B54+%2B32971+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5477935410888586306" border="0" /></a><br /><br /><span style="font-size:180%;">+35267 Hz</span><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZIjvVGFN2PybFCL3cb_xYAbh4qeEj85_lE5rsTGxJexbLp2tpl7m4WMZWteXEbywcx8bUTkpuSRHEKrxieQ7-AXCXykhz7yTkN7R4h1zu-Kk60yWTzbRn2mWNhx3eDTOwIJlB/s1600/PSR+B0329%2B54+auto+drift+rate+%2B0.1144+Hz:sec+60%25.png"><img style="margin: 0pt 0pt 10px 10px; float: right; cursor: pointer; width: 156px; height: 40px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZIjvVGFN2PybFCL3cb_xYAbh4qeEj85_lE5rsTGxJexbLp2tpl7m4WMZWteXEbywcx8bUTkpuSRHEKrxieQ7-AXCXykhz7yTkN7R4h1zu-Kk60yWTzbRn2mWNhx3eDTOwIJlB/s200/PSR+B0329%2B54+auto+drift+rate+%2B0.1144+Hz:sec+60%25.png" alt="" id="BLOGGER_PHOTO_ID_5477995040453561282" border="0" /></a>Another drifting-random-walk. The Auto Drift rate measurement reports that this signal is drifting at a +0.1144 Hz/sec rate. Note that horizontal zoom was changed to Hz=2X so the wide frequency drift would fit on the screen.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2qWs_K3gMjtmmQjevfkrQyUMXsBKV2b_Chtp28suh9ZQ57zalmC6Xb_wChmcCuBoI-4tni2K32XX4pQL1jZDw3IyJbSnTmzqAXhpPYo9kwUeod_yTGlj879LtoRx77tTMUnjV/s1600/PSR+B0329%2B54+%2B35242+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2qWs_K3gMjtmmQjevfkrQyUMXsBKV2b_Chtp28suh9ZQ57zalmC6Xb_wChmcCuBoI-4tni2K32XX4pQL1jZDw3IyJbSnTmzqAXhpPYo9kwUeod_yTGlj879LtoRx77tTMUnjV/s400/PSR+B0329%2B54+%2B35242+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476382760293384002" border="0" /></a><br />The signal starts at +35242 Hz, wiggles for about 100 seconds, and then begins a fast +65.89 Hz / 360 seconds = +0.1830 Hz/sec drift rate. The drift rate undergoes multiple acceleration changes The discrepancy with the auto drift rate measurement window is because Auto Drift calculated its highest energy drift at one of the slower linear sections. The Auto Drift algorithm is designed to work with constant drift rates but it works surprisingly well with a signal that undergoes multiple rate changes.<br /><br /><br /><span style="font-size:180%;">+36680 Hz</span><br />A drifting-random-walk with a -5.53 Hz / 520 seconds = -0.0106 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgj3cyxcuDUQEiSQljPsogVy_mdHgeMyPERc_s24_jv-MzzpfFHvdOuM2wRdYwwHsYGYiAg27jPIP7u6OxZfFcYu1LKFESa5jf4kUNOULTHRHBeLollUfaxvZO2eoyCytu5q5LV/s1600/PSR+B0329%2B54+%2B36680+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgj3cyxcuDUQEiSQljPsogVy_mdHgeMyPERc_s24_jv-MzzpfFHvdOuM2wRdYwwHsYGYiAg27jPIP7u6OxZfFcYu1LKFESa5jf4kUNOULTHRHBeLollUfaxvZO2eoyCytu5q5LV/s400/PSR+B0329%2B54+%2B36680+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476034655755109330" border="0" /></a><br /><br /><span style="font-size:180%;">+37186 Hz</span><br />A drifting-random-walk with a +26.30 Hz / 520 seconds = +0.05058 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG07IT86KAi9sYiav0ynyoX0Jt8DZQBVxLho3Gnn3vxnV2kMfTE4buffv6NG_YnHz2Ihn1pWSU6MM7ETOEfpxtbSOsDvzguzL3FO7RW4vlOHrt57n6ANJ0nmSm5B8ObY2IzW1c/s1600/PSR+B0329%2B54+%2B37186+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG07IT86KAi9sYiav0ynyoX0Jt8DZQBVxLho3Gnn3vxnV2kMfTE4buffv6NG_YnHz2Ihn1pWSU6MM7ETOEfpxtbSOsDvzguzL3FO7RW4vlOHrt57n6ANJ0nmSm5B8ObY2IzW1c/s400/PSR+B0329%2B54+%2B37186+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476037188369537970" border="0" /></a><br /><br /><span style="font-size:180%;">+38746 Hz "sisters"</span><br />It looks like these two drifting-random-walking sisters cross over each other, it is difficult to discern, but it could of been a random-walk "bounce." Assuming a cross-over, they are moving at -23.89 Hz / 520 seconds = -0.04594 Hz/sec and +27.08 Hz / 520 seconds = +0.05208 Hz/sec drift rates. Very similar drift rates but in opposite directions.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgw9gSR5gvjWlY1oqUyqu1xaDNSXy_f4GP3BpUSHxbSaAOI3viwpTZy4YrL7xFuR30RaIu4mqfgOlnsHUJ0DVy9Or0yz8b7WAE3AIzHAdeUbpolh1jg4QEz0LzxGcVJr7MhUc6G/s1600/PSR+B0329%2B54+%2B38746+Hz+sisters.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgw9gSR5gvjWlY1oqUyqu1xaDNSXy_f4GP3BpUSHxbSaAOI3viwpTZy4YrL7xFuR30RaIu4mqfgOlnsHUJ0DVy9Or0yz8b7WAE3AIzHAdeUbpolh1jg4QEz0LzxGcVJr7MhUc6G/s400/PSR+B0329%2B54+%2B38746+Hz+sisters.png" alt="" id="BLOGGER_PHOTO_ID_5476043898688210370" border="0" /></a><br />It is difficult to tell with this low <a href="http://baudline.com/manual/glossary.html#SNR">SNR</a> but it looks like the right sister near the bottom undergoes a bifurcation to 2 and then back to 1. These sisters share what appears to be several minor feature wiggles in a mirror reflection symmetry. So they are related tightly in frequency and loosely in distinctive characteristics. This is a significant find and might have importance in determining what sort of mixing is causing all of these drifting random walks.<br /><br /><br /><span style="font-size:180%;">+39190 Hz<br /></span>A strong drifting-random-walk with a -9.96 Hz / 520 seconds = -0.0192 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5dmsKkdH0UjZi5bvSsT46YxuQwfzAmhJ6nCEx92voRKvxTPxMu2jaYZUmCFzfSa3_umF5S2HKVgrg-KYiJaeedtoQuzbzykHjdOsgNzPCo-O9UA8vD7m-Fgd_h2m_kWOQlUXD/s1600/PSR+B0329%2B54+%2B39190+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5dmsKkdH0UjZi5bvSsT46YxuQwfzAmhJ6nCEx92voRKvxTPxMu2jaYZUmCFzfSa3_umF5S2HKVgrg-KYiJaeedtoQuzbzykHjdOsgNzPCo-O9UA8vD7m-Fgd_h2m_kWOQlUXD/s400/PSR+B0329%2B54+%2B39190+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476049947746791234" border="0" /></a><br /><br /><span style="font-size:180%;">+39623 Hz<br /></span>A weak wildly drifting-random-walk with a -9.64 Hz / 520 seconds = -0.0185 Hz/sec drift rate. The <a href="http://baudline.com/manual/process.html#auto_drift">Auto Drift</a> algorithm was used for a little additional extraction of this weak signal.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_1Toe32q2YgoNsrgorloc0Lon5Jy8X7a63hxsG1WINh9OhA_jWhqqxd-ADlr_JC0Iswef5byXKtsDoHNTxNqEtVFirlRF6gFmi-URGD-18vxKP0pIEgBntQr_XW2mq6Hyo6SN/s1600/PSR+B0329%2B54+%2B39623+Hz+autodrift.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_1Toe32q2YgoNsrgorloc0Lon5Jy8X7a63hxsG1WINh9OhA_jWhqqxd-ADlr_JC0Iswef5byXKtsDoHNTxNqEtVFirlRF6gFmi-URGD-18vxKP0pIEgBntQr_XW2mq6Hyo6SN/s400/PSR+B0329%2B54+%2B39623+Hz+autodrift.png" alt="" id="BLOGGER_PHOTO_ID_5476052569916329602" border="0" /></a><br /><br /><span style="font-size:180%;">+40212 Hz</span><br />A drifting-random-walk with a -7.42 Hz / 520 seconds = -0.0143 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfGwWEIVMvb7PaBOVQwJh2D0kxYOIVeYIHjp130WPTn_lZqjT6fp-r4CjgX71CS4ioTRXEbAaq9yacGXfC_sxLRJJzRn0o9zWxeEImA1IqxNUohSTYi9B9myAiCDWJsPUG-o_a/s1600/PSR+B0329%2B54+%2B40212+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfGwWEIVMvb7PaBOVQwJh2D0kxYOIVeYIHjp130WPTn_lZqjT6fp-r4CjgX71CS4ioTRXEbAaq9yacGXfC_sxLRJJzRn0o9zWxeEImA1IqxNUohSTYi9B9myAiCDWJsPUG-o_a/s400/PSR+B0329%2B54+%2B40212+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476057498269932514" border="0" /></a><br /><br /><span style="font-size:180%;">+44492 Hz<br /></span>A strong drifting-random-walk that has a very large negative curvature with a +4.62 Hz / 520 seconds = +0.00888 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheS32doxwmRijL1S01oRpHqpugBp0qe10mkxNeEK3ctcNamSBQmexCdd3QkrVZuv-jIYU8heOdzD_laiCdNrTvnjb__B5PK3QMlZja_5-CxoMBrl_bbbH3PWsb3SrfQq5pfHLB/s1600/PSR+B0329%2B54+%2B44492+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheS32doxwmRijL1S01oRpHqpugBp0qe10mkxNeEK3ctcNamSBQmexCdd3QkrVZuv-jIYU8heOdzD_laiCdNrTvnjb__B5PK3QMlZja_5-CxoMBrl_bbbH3PWsb3SrfQq5pfHLB/s400/PSR+B0329%2B54+%2B44492+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476067584427265218" border="0" /></a><br /><br /><span style="font-size:180%;">+45504 Hz<br /></span>A drifting-random-walk with a +12.70 Hz / 520 seconds = +0.02442 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9cKES1NrCJf1F_kPe4ycVkm7p8I7DThI3fFJy0rp0FJbPnjWT_uRbqzpbMJaDmlAn42FOfxLsqu9KHOH6oCRoJ19twiVedrwMv9_HLyVdy3dwoG-XjK1iFJWrEmw8YOl2wdvA/s1600/PSR+B0329%2B54+%2B45504+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9cKES1NrCJf1F_kPe4ycVkm7p8I7DThI3fFJy0rp0FJbPnjWT_uRbqzpbMJaDmlAn42FOfxLsqu9KHOH6oCRoJ19twiVedrwMv9_HLyVdy3dwoG-XjK1iFJWrEmw8YOl2wdvA/s400/PSR+B0329%2B54+%2B45504+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476069463284030578" border="0" /></a><br />The discontinuous jumps make this signal interesting. It almost looks like <a href="http://baudline.com/manual/glossary.html#FSK">FSK</a> with a 1.4 Hz mark-space spread and 17.391 second cycle (0.0575 baud) rate. Measurements were make with baudline's <a href="http://baudline.com/manual/display.html#delta_measurement_bars">click-shift-drag mechanism</a> and <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a>. Here is a quick and likely very error prone demodulation:<br /><br />00-00--00--0+0-00+0-+-00+-00-0<br /><br />Where the symbols {-, 0, +} are deltas that denote a negative, a zero, or a positive jump in frequency. Starting at 6 that delta stream translates to:<br /><br />665554333211221112212111211100<br /><br />This likely has a lot of errors but the information that should be extracted here are the single bit transitions and the runs of 2 or 3 consecutive bits and whether they are caused by a negative or a positive frequency transition.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeDgtxJogulwSnuoQGvlA4uPlJCcNMWsiN87GDsV_B2kH10es7I_1VXS6hMo2sfuFskrlR8Yw7YHp8l3QwFjrqYVQ3ZLJMR4Ifyi-BgqtfcWpGF3AyCHycf_ijUfh3AZVrIL1w/s1600/PSR+B0329%2B54+%2B45504+Hz+periodicity+bars.png"><img style="margin: 0pt 0pt 10px 10px; float: right; cursor: pointer; width: 123px; height: 99px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeDgtxJogulwSnuoQGvlA4uPlJCcNMWsiN87GDsV_B2kH10es7I_1VXS6hMo2sfuFskrlR8Yw7YHp8l3QwFjrqYVQ3ZLJMR4Ifyi-BgqtfcWpGF3AyCHycf_ijUfh3AZVrIL1w/s200/PSR+B0329%2B54+%2B45504+Hz+periodicity+bars.png" alt="" id="BLOGGER_PHOTO_ID_5476082342626561762" border="0" /></a><br />Demodulating a weak and drifting random wiggling signal is very difficult. If you would like to take a crack at it then click on the small image on the right that already has the periodicity bars overlaid. Good luck.<br /><br /><br /><span style="font-size:180%;">+1008460 Hz<br /></span>This interesting signal is of hydrogen's upper sideband. Note the horizontal zoom has been change to Hz=2X so that the signal fits on the screen. It looks like two groups of 7 Hz wide noise that are drifting at different rates. The first has a +38.8 Hz / 144 seconds = +0.269 Hz/sec drift rate. The second has a + 65.6 Hz / 169 seconds = +0.388 Hz/sec drift rate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhD8JKQqHK1EPN-WzU6NzhXEI3qKocPRne2tXmBAwLHuawpOlIAQvT-dBjqJAW2xAOid5lEF9MD8u8U4qIkzintCbSzyD4fFt6EYgituOxWMHdoxG135hOHkSPkEvlARW8og5Uj/s1600/PSR+B0329%2B54+%2B1008460+Hz+upper.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 367px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhD8JKQqHK1EPN-WzU6NzhXEI3qKocPRne2tXmBAwLHuawpOlIAQvT-dBjqJAW2xAOid5lEF9MD8u8U4qIkzintCbSzyD4fFt6EYgituOxWMHdoxG135hOHkSPkEvlARW8og5Uj/s400/PSR+B0329%2B54+%2B1008460+Hz+upper.png" alt="" id="BLOGGER_PHOTO_ID_5476396496067429138" border="0" /></a><br />It also looks like the start of each group consists of three distinct pulses separated by brief pauses. Both signals start with a 40 second pulse, a 10 second pause, a strong middle section, and then a fading tail.<br /><br /><br /><span style="font-size:180%;">Side Skirting</span><br />I usually ignore signals located in the ADC or quadrature filter roll-offs (side skirts) because they are in a section of spectrum that was meant to be filtered away. Signals in the side skirts are usually weaker and they may be due to out-of-band signal leakage. But these side skirting signals are interesting and they may be important in solving the mystery of the rich signal nursery. Here is a full width Average spectrum of the entire bandwidth:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoldqGcxP0NP1a7Izjx1wXbRg4qcFb25NVnWFMZrMTbxN9ffCK-EQu-PtofmIDE99nOJs7kkq4J0_P3eAFuNqpGRUMuchQhQKu185I6YxQL-zGKkQ7RDOgTAcyA9Swql4M5jlB/s1600/0329+54+average+Hz%3D1X.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 153px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoldqGcxP0NP1a7Izjx1wXbRg4qcFb25NVnWFMZrMTbxN9ffCK-EQu-PtofmIDE99nOJs7kkq4J0_P3eAFuNqpGRUMuchQhQKu185I6YxQL-zGKkQ7RDOgTAcyA9Swql4M5jlB/s400/0329+54+average+Hz%3D1X.png" alt="" id="BLOGGER_PHOTO_ID_5481696384499271778" border="0" /></a><br />Of interest are the three signals that are in the side skirts that are underneath the green dots. They will each be decimated by 4096 for a 0.0651 Hz/bin resolution and investigated in more detail below.<br /><br /><br /><span style="font-size:180%;">-3321665 Hz</span><br />A drifting wideband noise signal that looks like it is in the same family as the +1008460 Hz signal. The signal is drifting at -65.6 Hz / 520 seconds = -0.126 Hz/sec drift rate. Note that the horizontal zoom is set to Hz=2X.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF2QwiTPij8ozQa8w-PmXBmHLVDpESqmbgDIV1oVNXDWbN4valOwPGK7xrb7Oj4uDbPR2B3qaWr9zzs4AHCZtqW-QlOfd7gQLs7ImKrE1FNDuJBZs1qa46Vzru6RHu1ztjy3SH/s1600/0329+54+-3312665+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 368px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF2QwiTPij8ozQa8w-PmXBmHLVDpESqmbgDIV1oVNXDWbN4valOwPGK7xrb7Oj4uDbPR2B3qaWr9zzs4AHCZtqW-QlOfd7gQLs7ImKrE1FNDuJBZs1qa46Vzru6RHu1ztjy3SH/s400/0329+54+-3312665+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5482007092668521058" border="0" /></a><br />This looks like 8 pulses that are spaced about 61 seconds apart from each other.<br /><br /><br /><span style="font-size:180%;">+3469083 Hz</span><br />Another drifting wideband noise signal. This signal is drifting at +157.0 Hz / 520 seconds = +0.302 Hz/sec drift rate. Note that this signal is drifting so fast that the horizontal zoom had to be set to Hz=8X so that it would all fit on the screen.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKADpL3UFvtyHLjrldkNtwu7PD1zqUNIu96D7YEowoideXm6H1zDTtxUFRwSjxWW214BNESuVDlF_nI_IlkA7zQOBLHlyg4Ig-xXC8GSNL2Do_lvBM1ovjR5aKAgY-2YZr7gJ7/s1600/0329+54+%2B3469083+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 361px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKADpL3UFvtyHLjrldkNtwu7PD1zqUNIu96D7YEowoideXm6H1zDTtxUFRwSjxWW214BNESuVDlF_nI_IlkA7zQOBLHlyg4Ig-xXC8GSNL2Do_lvBM1ovjR5aKAgY-2YZr7gJ7/s400/0329+54+%2B3469083+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5481691991023487234" border="0" /></a><br /><br /><span style="font-size:180%;">+4315733 Hz</span><br />This far right skirt section is 5 dB down from the main flat part of the spectrum near Hydrogen. Using baudline's <a href="http://baudline.com/manual/measurements.html#fundamental_Hz_dB_PSD">fundamental Hz</a> window this very strong stationary tone was accurately measured to be 4315733.185 Hz. This number is interesting because 4315733.185 / 8738133 * 4096 = 2023.0000076 which is very close to the whole number 2023. Note that 2^12 = 4096 and it will also be derived below in the <span style="font-weight: bold;">Quadrature Magnitude</span> section in relation to 25600 Hz. Nothing is special about the number 2023 but I suspect that it is somehow important to the ATA's beamformer-decimator DSP code or filter banks.<br /><br />Below is an annotated Average spectrum view that has been zoomed in and centered at the strong 4315733.185 Hz tone.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3whJlOUUCqKc_CSF6sFvbRetSg1aDiit7gZFuxVUL_jo89-CrFKvbvImtQbMPl_xZ31Hc6jNu-Bjy8Ot14bynEtYo4bsRPf7qTflvZY7SXeFiYSuqDypwv9Nx3nRex2k9d3ds/s1600/0329+54+average+4315733Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 155px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3whJlOUUCqKc_CSF6sFvbRetSg1aDiit7gZFuxVUL_jo89-CrFKvbvImtQbMPl_xZ31Hc6jNu-Bjy8Ot14bynEtYo4bsRPf7qTflvZY7SXeFiYSuqDypwv9Nx3nRex2k9d3ds/s400/0329+54+average+4315733Hz.png" alt="" id="BLOGGER_PHOTO_ID_5481698483970117810" border="0" /></a><br />The blue sidebands were accurately measured to be <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±</span></span>120.009 Hz from the center carrier frequency. The yellow sidebands are <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±50.004 Hz away from the center.</span></span> The green dot peak is +76.631 Hz from the center frequency. It is interesting that there is no sign of 60 Hz sidebands despite the presence of strong 120 Hz sidebands.<br /><br />So what is the significance of these sideband delta Hz numbers? I'm not sure but there are a number of unique whole number ratios. Such as 120 / 50 * 100 / 12 = 20. Note that the raw ATA sample rate is 100 * 2 ^ 20 which is then decimated by 12. Also 76.631 / (120 - 50) * 1024 = 1121.002 which is the whole number 1121 when accounting for Hz measurement error. Again, the whole numbers 20 and 1121 have no particular significance other than probably being deeply embedded in the ATA's DSP code.<br /><br />This waveform plot shows how the energy of this slice of spectrum varies over time (from left to right). The magnitude time domain operation along with the Waveform window's new prototype sum() option were used to create this plot.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSKI_ZWQSg2yz8n-1uSmUEWMfBJ8ylb8dFfeNPGarxKESXJpK73oE7EYS4laui2qCYRuG7Ja78b9CH7akCCM46u39fgFTdvUwKbnMZpaPfnwt0Lwy2cEqACjmdoiNhOl9kPgrD/s1600/0329+54+waveform+sum%28quadrature+magnitude%29.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 121px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSKI_ZWQSg2yz8n-1uSmUEWMfBJ8ylb8dFfeNPGarxKESXJpK73oE7EYS4laui2qCYRuG7Ja78b9CH7akCCM46u39fgFTdvUwKbnMZpaPfnwt0Lwy2cEqACjmdoiNhOl9kPgrD/s400/0329+54+waveform+sum%28quadrature+magnitude%29.png" alt="" id="BLOGGER_PHOTO_ID_5481978243572947090" border="0" /></a>These energy fluctuations in the waveform view have some unusual periodic humps and discontinuities. Here is a zoomed in spectrogram of main center tone:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSDBfsA7V_SYmdIuvj9aJRTGrxQIp-RRItWP-Wb40tWZ1wmnacTEsf7Ra_NAHAkz00figxTU16Yygiwk6a0UeM8tY_FwO4XE5kSASGk1HHqkfMLV7yaHXIBavO6Wdl8bBI3K51/s1600/0329+54+%2B4316733+Hz+mag.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 356px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSDBfsA7V_SYmdIuvj9aJRTGrxQIp-RRItWP-Wb40tWZ1wmnacTEsf7Ra_NAHAkz00figxTU16Yygiwk6a0UeM8tY_FwO4XE5kSASGk1HHqkfMLV7yaHXIBavO6Wdl8bBI3K51/s400/0329+54+%2B4316733+Hz+mag.png" alt="" id="BLOGGER_PHOTO_ID_5482039669345148738" border="0" /></a><br />A nice strong stationary tone. The fluctuations of the center tone match what was seen in the Waveform window. Let us take a look at the <span style="font-weight: bold;">phase</span> of this tone with the <span style="font-weight: bold;">blip Fourier</span> transform. Click on the image below for a more detailed view.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhv6EAIk4td4LeLdUE90E7iPfMTUd_D2ixlQ7ABK8fq7NEO_me-U7dJvoZEU_U-vYy-AIO6VLjlSkbt6d5xvnXVMN6CCVuNI54hPTTvusL4TjtQBxBRLXjyFPBw4ey6IsbGJPGG/s1600/0329+54+%2B4316733+Hz+phase.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 350px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhv6EAIk4td4LeLdUE90E7iPfMTUd_D2ixlQ7ABK8fq7NEO_me-U7dJvoZEU_U-vYy-AIO6VLjlSkbt6d5xvnXVMN6CCVuNI54hPTTvusL4TjtQBxBRLXjyFPBw4ey6IsbGJPGG/s400/0329+54+%2B4316733+Hz+phase.png" alt="" id="BLOGGER_PHOTO_ID_5482044214080592466" border="0" /></a>Notice that the phase slowly rolls and then an abrupt phase shift occurs. These discontinuities happen about five different times. This is extremely unusual for a constant stationary tone.<br /><br />Next let us take a look at the -120 Hz sideband tone by zooming in on the Average display.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgl8RdIpiIbyZo6nHxmj-vxGCn8J_RKGs5jTH13yBGmbyIaDoh1TisE0KjZN9C58MJSYYcdMH8jGbj4QVo5helR970N8ZSJZlxZ_3ITPvRR0fyy8D2FvKosd-DNitAX1kB5fu-Z/s1600/0329+54+average+-120+Hz+two+tones.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 154px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgl8RdIpiIbyZo6nHxmj-vxGCn8J_RKGs5jTH13yBGmbyIaDoh1TisE0KjZN9C58MJSYYcdMH8jGbj4QVo5helR970N8ZSJZlxZ_3ITPvRR0fyy8D2FvKosd-DNitAX1kB5fu-Z/s400/0329+54+average+-120+Hz+two+tones.png" alt="" id="BLOGGER_PHOTO_ID_5482038882532194210" border="0" /></a><br />That looks like two tones that are very close together. What is going on here? We need to explore this further. Let us zoom in a bit more by decimating by an additional factor of 8 for a 0.00814 Hz/bin resolution.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhi8sRMw2hLAyeJ_7On4js_1kPTvvB94xpxiglUvXDl0EYfCQouQcH_Z3Ah-_RglnmaHZXPkVm2DZ-Iu_U3flZjs1I3Z-wymYcn0QJyekTDljxnQoTux07YD_nPKoiKz1OObxVg/s1600/0329+54+-120+Hz+0.00814+Hz:bin.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 155px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhi8sRMw2hLAyeJ_7On4js_1kPTvvB94xpxiglUvXDl0EYfCQouQcH_Z3Ah-_RglnmaHZXPkVm2DZ-Iu_U3flZjs1I3Z-wymYcn0QJyekTDljxnQoTux07YD_nPKoiKz1OObxVg/s400/0329+54+-120+Hz+0.00814+Hz:bin.png" alt="" id="BLOGGER_PHOTO_ID_5482052584652938322" border="0" /></a>Now it's three tones! This is getting stranger and stranger. The spacing between those three tones is 0.18170 Hz and 0.09534 Hz.<br /><br />Next, let us move the down mixer back to the center carrier frequency at 4315733.185 Hz and see what is going on there.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8bHwTNVY6TjKNwpaZRSjYkiu7uY-h7x5Yyk-k7ue3a7O9Ks92Pe36ih6Q0feZmgMrT2XXGMHGbwh2PoZaC0XvL0V7hse6gXzLATJXdaXGB0Gs2YOuWn8oAEmk7ZbSJEElF5WR/s1600/0329+54+center+0.00407+Hz:bin.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 155px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8bHwTNVY6TjKNwpaZRSjYkiu7uY-h7x5Yyk-k7ue3a7O9Ks92Pe36ih6Q0feZmgMrT2XXGMHGbwh2PoZaC0XvL0V7hse6gXzLATJXdaXGB0Gs2YOuWn8oAEmk7ZbSJEElF5WR/s400/0329+54+center+0.00407+Hz:bin.png" alt="" id="BLOGGER_PHOTO_ID_5482059408852408130" border="0" /></a><br />That doesn't look like a single distinct carrier tone anymore. There are four tones in there. Let's dive deeper still, decimate by an additional factor of 8, and zoom in for a 0.00102 Hz/bin resolution which is approximately the spectral limit for this amount of data.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0PI2w9i3p_GVWLJRrW4mZRgSylEA1rVDHVpEbjfQj4fGXU-s2_WfEZvsohgfEzFsQCdZJ21iZzd7BOTdXMJD-PisiJULaKrxCThsVcP-day6Jk7yFfltJZ6zP4N_Cha92fZsr/s1600/0329+54+center+0.00102+Hz:bin.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 155px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0PI2w9i3p_GVWLJRrW4mZRgSylEA1rVDHVpEbjfQj4fGXU-s2_WfEZvsohgfEzFsQCdZJ21iZzd7BOTdXMJD-PisiJULaKrxCThsVcP-day6Jk7yFfltJZ6zP4N_Cha92fZsr/s400/0329+54+center+0.00102+Hz:bin.png" alt="" id="BLOGGER_PHOTO_ID_5482060290523209138" border="0" /></a><br />Now the center carrier consists of 8 tones! This looks like a narrower version of the modulated signal seen in the Exoplanet 060 analysis. Too bad we can't zoom in anymore because this fractal-like structure is becoming extremely fascinating. What we saw above as power fluctuations of the main carrier tone were actually beat frequencies. One way to create a structure like this is to sum together a number of pure tones that are slightly offset in frequency. Could a beam former that is steering the delays of 42 different antennas create something like this?<br /><!-- <span style="font-size:180%;">Where are the Pulses?<br /></span>It is known that PSR B0329+54 has a 0.714519 second period and it is the strongest pulsar visible from Earth. A pulsar is a form of wideband modulation with a very constant baud rate. I've tried looking at the Waveform display, the Autocorrelation transform, zooming in on the spectrogram, decimating, and using a number of other features in baudline. I can find plenty of drifting weak signals in the data file but I can't find any pulses. So where are the pulses? Either I'm doing something very wrong or the data is phase mangled and the pulses are smeared together.<br /><br />I know that higher frequency components arrive earlier than the lower frequency components due to propagation through the interstellar medium (ISM). I also know that it is custom in pulsar research to apply a de-dispersion algorithm to correct for this and that an operation of folding many pulses on top of each other is done to improve the SNR. Are these techniques required in order to see even a faint trace of the pulses from the strongest pulsar in the sky? If so then I am amazed that they were able to discover pulsars with the technology they had 40 years ago.<br />--><br /><br /><span style="font-size:180%;">Seeing the Pulses<br /></span>Visualizing the pulsar's pulses defied traditional signal analysis techniques. No hint of the pulses were visible in the frequency domain, instead a time domain technique was required. Here were the steps. Decimation by 4 with the down mixer moved to a clean chunk of spectrum to the left of Hydrogen. Then the down-mixed quadrature data had the <span style="font-weight: bold;">magnitude</span> operation applied in the time domain. Finally the <a href="http://baudline.com/manual/waveform.html#waveform">Waveform</a> display used a prototype summing feature with a timebase zoom of 32768X.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpF7YJchXlTxF7Bb3N7Fqa_SP9gviqUxEQ4nYtBXDM192ae7xrojQkDUzMJAjnFxPpgWMj9YRBZI7wkOwLiY29V1621Fd8TO9P61dn5wgv-KF6ZsTbW3_4zE2SMHRFdFeWJx15/s1600/0329+54+waveform+pulsar+sum+d4.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 86px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpF7YJchXlTxF7Bb3N7Fqa_SP9gviqUxEQ4nYtBXDM192ae7xrojQkDUzMJAjnFxPpgWMj9YRBZI7wkOwLiY29V1621Fd8TO9P61dn5wgv-KF6ZsTbW3_4zE2SMHRFdFeWJx15/s400/0329+54+waveform+pulsar+sum+d4.png" alt="" id="BLOGGER_PHOTO_ID_5482414114932261762" border="0" /></a><br />There are 19+ pulses visible in the above Waveform display. Baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodic bars</a> measured the pulse periodicity to be 0.71455 seconds which is fairly close to the published 0.714519 second value. The accuracy of this measurement is impressive considering only 17 seconds of data were used.<br /><br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiklK8323l4FvImFBXB4wTyTu0N8n_AenMLyD-Pwgz3ITkS62BgPS15FDsW1aqWA8f3RPqxXWBLIL14hxegs-YiXQbzSuNNfZtl1DMGxlhSpdFC54A0-63Q1_3HVtTWfW_ZY9xZ/s1600/polka_dotted_elephant.jpg"><img style="margin: 0pt 0pt 10px 10px; float: right; cursor: pointer; width: 94px; height: 75px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiklK8323l4FvImFBXB4wTyTu0N8n_AenMLyD-Pwgz3ITkS62BgPS15FDsW1aqWA8f3RPqxXWBLIL14hxegs-YiXQbzSuNNfZtl1DMGxlhSpdFC54A0-63Q1_3HVtTWfW_ZY9xZ/s200/polka_dotted_elephant.jpg" alt="" id="BLOGGER_PHOTO_ID_5477135526182592562" border="0" /></a><span style="font-size:180%;">Quadrature Magnitude<br /></span>Baudline's Input Mapping <a href="http://baudline.com/manual/channel_mapping.html#operation">time domain operation</a> was set to quadrature <span style="font-weight: bold;">magnitude</span> to see the Fourier power envelope. Gone are the large elephants that were at 1/3, 2/3, and 3/3 Nyquist in the <a href="http://baudline.blogspot.com/2010/05/setiquest-exoplanet-060.html">Exoplanet 060</a> data. This Average spectral plot was done with no decimation.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisOnVmOTCHDeX_HexiYXW74V-j9gtrRrT4wLjPYggVDimEg3TXRdHvc_1RKT1vAxPdG3LlHbdZI7IqLAHzDErr7Z48gOosB9rqmRE9Sfl5EDNkNzwnakgfqyp85i_BM92bpkXa/s1600/PSR+B0329%2B54+quadrature+mag+25600+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 154px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisOnVmOTCHDeX_HexiYXW74V-j9gtrRrT4wLjPYggVDimEg3TXRdHvc_1RKT1vAxPdG3LlHbdZI7IqLAHzDErr7Z48gOosB9rqmRE9Sfl5EDNkNzwnakgfqyp85i_BM92bpkXa/s400/PSR+B0329%2B54+quadrature+mag+25600+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5476867375038205986" border="0" /></a><br />Notice the strong tone at 25600 Hz and 9 of its harmonics. Using the Average window, the <a href="http://baudline.com/manual/measurements.html#fundamental_Hz_dB_PSD">fundamental Hz measurement</a> display, and a higher order harmonic the frequency was carefully measured to be 25600.0 Hz with an error of less than <span style="visibility: visible;" id="main"><span style="visibility: visible;" id="search">±</span></span>0.1 Hz. <span style="font-size:100%;">The ATA's ADC sample rate 100 * 2^20 / 25600 Hz = 4096. This suspicious power of 2 number suggests that these distortion products are related to the ADC or its follow on processing prior to and including the decimation by 12 stage.</span><br /><br />When baudline's decimation is set to 2 and the down mixer is moved the 25600 Hz tone and harmonics remain stationary. This is just like the elephant polka music on every radio channel analogy mentioned in the <a href="http://baudline.blogspot.com/2010/05/setiquest-exoplanet-060.html">Exoplanet 060 data analysis</a>. In that same 060 analysis the <span style="color: rgb(102, 255, 255);">cyan</span>, <span style="color: rgb(204, 51, 204);">magenta</span>, <span style="color: rgb(255, 255, 51);">yellow</span>, and <span style="color: rgb(255, 204, 0);">orange</span> tones had sidebands with delta offsets of 25600 Hz. Since that time something in the ATA was fixed and those sidebands are missing in this 0329+54 data.<br /><br />Next, a look at 60 Hz by using the quadrature <span style="font-weight: bold;">magnitude</span> operation with the Fourier transform and decimating by 256 for a 0.5208 Hz/bin resolution.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGHlDhKPzUrnDirXOqOKb-Oai2zUnNqZDEuki2FasbnX0d4qtYOsDHm5M1_U6V6MzGilyV6ddOZ2cL27n6ItMoFNHvtyutVNpQi8ywQcnghMiTDePVYtrYdx3Rz26JS-kemiED/s1600/PSR+B0329%2B54+quadrature+mag+average+60+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 154px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGHlDhKPzUrnDirXOqOKb-Oai2zUnNqZDEuki2FasbnX0d4qtYOsDHm5M1_U6V6MzGilyV6ddOZ2cL27n6ItMoFNHvtyutVNpQi8ywQcnghMiTDePVYtrYdx3Rz26JS-kemiED/s400/PSR+B0329%2B54+quadrature+mag+average+60+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5477123077884944882" border="0" /></a><br />The exact frequency is 59.930 Hz and 8 harmonics are visible. These tones also remain stationary when the down mixer tuning frequency is adjusted. The 60 Hz tone is doing something else interesting as a function of time. Below is the accompanying spectrogram display:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0ACKVyHA-ZQhhy_mk0lQwuV3P8238V_Q4-7QF_T-N4uSvdsxoYqbb3z24Db8UslayPSuvR0-sHjxYcTgSCzl8MzWRuXx83Q1tQvsoX1StJLeOEOViRXbuSGog5EQ0ubpp_4KX/s1600/PSR+B0329%2B54+quadrature+mag+spectro+60+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 376px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0ACKVyHA-ZQhhy_mk0lQwuV3P8238V_Q4-7QF_T-N4uSvdsxoYqbb3z24Db8UslayPSuvR0-sHjxYcTgSCzl8MzWRuXx83Q1tQvsoX1StJLeOEOViRXbuSGog5EQ0ubpp_4KX/s400/PSR+B0329%2B54+quadrature+mag+spectro+60+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5477123737825023026" border="0" /></a><br />Baudline's periodicity bars measured the 60 Hz pulsing to be at a roughly 21 - 22 second period. The 120 Hz tone is undergoing its own pulsing at an unrelated and somewhat random period. The pulsing period is different enough from the baud rate seen in the FSK signal at +45504 Hz that it is not likely related.<br /><br /><br /><span style="font-size:180%;">Filter Extraction<br /></span>The impulse response transform was used to compare the I and Q channels. It should be noted that because of the stimulus source being very white noise-like the cross-correlation produces a similar image. Also note that the horizontal axis should be time lag (not Hz) and the vertical axis should be a linear scale (not dB).<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbXeu1MKxkIFelBTdLONYUt6YPLiT72KfUN8lE97jYIqskHgrkH2LiuidGlEUFhT4RlRHW0ub4nSWVmx32GtgT1tTYWZa5DPzTpWlBLXfFBDEqlOAxqJ1U_3gA_sGPTGyVTM5X/s1600/PSR+B0329%2B54+average+impulse+response.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 223px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbXeu1MKxkIFelBTdLONYUt6YPLiT72KfUN8lE97jYIqskHgrkH2LiuidGlEUFhT4RlRHW0ub4nSWVmx32GtgT1tTYWZa5DPzTpWlBLXfFBDEqlOAxqJ1U_3gA_sGPTGyVTM5X/s400/PSR+B0329%2B54+average+impulse+response.png" alt="" id="BLOGGER_PHOTO_ID_5476867690283737970" border="0" /></a><br />This very unusual shape has an inverse symmetry for negative and positive lag. It also doesn't have any hints of being a Hilbert filter which is unusual for quadrature of a noise source. In the next image a Hilbert filter was applied to the I channel prior to calculating the impulse response. This effectively undoes quadrature.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy3S50RmtmPiB0zJ7wp9f7JPHPkKC1z5Hamr1PFJhW65dHiKcp-ds7CW-XmrnBoLhxBs-OAwZvIdPjCJOON3IZfos53JESyYe_xlDeg1IrbMzTribbWHW4hghIJ3ZeIowkIHxb/s1600/PSR+B0329%2B54+average+impulse+response+Hilbert.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 223px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy3S50RmtmPiB0zJ7wp9f7JPHPkKC1z5Hamr1PFJhW65dHiKcp-ds7CW-XmrnBoLhxBs-OAwZvIdPjCJOON3IZfos53JESyYe_xlDeg1IrbMzTribbWHW4hghIJ3ZeIowkIHxb/s400/PSR+B0329%2B54+average+impulse+response+Hilbert.png" alt="" id="BLOGGER_PHOTO_ID_5476869644576399266" border="0" /></a>This looks like a low pass filter (LPF) with a sharp even-odd notching in the center.<br /><br /><br /><span style="font-size:180%;">Conclusion<br /></span>The hydrogen has sidebands with a delta of 482 kHz which could be caused by signal distortion or by erroneous DSP error mixing products. Located at or near these sidebands are a large number of weak signals that have a wealth of unique characteristics. Some of these signals are worth further study and some effort will be required to successfully demodulate one of them. It is becoming apparent that a signal "nursery" to the left of the main feature seems to be a common theme in the setiQuest ATA signal data. The cause of this left-side preference is unknown.<br /><br />Baudline's Auto Drift algorithm found a couple of drifting signals that would of been missed in the standard analysis pass. The more experience we gain with the tools, the more it will allow us to refine our analysis technique and find more weak signals.<br /><br />The quadrature magnitude technique was used again and it found fairly strong 25600 Hz and 60 Hz elements that are omnipresent phase distortion products. It is possible that many of the interesting weak signals seen here have been caused by the mixing of these distortion products. The shear number and uniqueness of the weak signals suggest that this is not the sole cause though. This is an improvement from the previous Exoplanet 060 data file which had slightly more weak signals but those signal characteristics also had more symmetry.<br /><br />An extremely unusual fractal-like carrier tone was discovered in the side skirts that had 50 Hz and 120 Hz sidebands. Where did the 50 Hz come from? The 4096 buffer size pops up again.<br /><br />So we have a signal rich environment.<span style="font-style: italic;"> </span>It is like the haystack is made of needles, the problem of SETI is not finding the drifting weak signals but determining which ones are truly extraterrestrial and which ones are just local interference or internal noise. Some people have suggested constructing an EMI database as a tool to distinguish false signals. From what I have seen this approach will not work because the signals are everywhere and they seem to have an infinite variety of characteristics and behaviors. Possibly the multi-beam nulling method will prove to be a powerful discriminating tool. It should work well for local interference but internal DSP noise is a different animal. So it is possible that many of these weak signals will be unique to specific beams which would render this technique null. It would be extremely interesting to test this theory with a future ATA data set that contains multiple symmetrically nulled beams.<br /><br /><span style="font-style: italic;">[Note: Baudline can only handle 4 quadrature channels at a time, so no more than 4 complex beams per data file would be preferred.]<br /></span><span><br /><br /><span style="font-size:180%;">Links<br /></span></span><ul><li><span><a href="http://setiquest.org/forum/topic/baudline-analysis-psr-b032954">http://setiquest.org/forum/topic/baudline-analysis-psr-b032954</a></span></li></ul><span style="font-style: italic;"><span style="font-style: italic;"><br /></span></span></div>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-81454997841248385532010-05-13T17:22:00.000-07:002013-05-09T17:35:45.832-07:00setiQuest Exoplanet 060<div class="separator" style="clear: both; text-align: center;">
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<span style="font-size: 100%;">This analysis is of the <a href="http://setiquest.org/">setiQuest</a> Exoplanet 060 data file with the <a href="http://www.baudline.com/">baudline signal analyzer.</a> The quadrature data file has a base frequency of around 1420 MHz and a sample rate of 8.738133 Msamples per second. The 20 GB of data corresponds to about 19 minutes which are split into 10 files.<br /><br />The following command line was used to stream the Exoplanet 060 data files into baudline:<br /><br /><span class="Apple-style-span"><span class="Apple-style-span" style="font-size: small;">cat 2010-03-19-exo060-8bit-* | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133.33 -fftsize 65536 -pause -utc 0</span></span><br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Full 8.738 MHz view</span><br />The Exoplanet 060 files were streamed into baudline's standard input. A 65536 point FFT was used for a bin resolution of 266.667 Hz/bin. Optimal anti-alias beam slices were used to smooth the spectrogram and the Color Aperture window was tweaked to maximize the color resolution.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1rfjNGjohPq7utc8D7CRDcEpN0BjH3UJzmnmopyiLl0LAcYJ2tQ0-mJ69kQqLr0aIhOGLwbU52NifKKbPr3-W6imZd8GPjWVVu5nolVIwbjd40kto_-FiQG5UnuDLBvP4n1j3/s1600/exo+060+Screen+shot+2010-05-08+at+4.13.14+PM.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1rfjNGjohPq7utc8D7CRDcEpN0BjH3UJzmnmopyiLl0LAcYJ2tQ0-mJ69kQqLr0aIhOGLwbU52NifKKbPr3-W6imZd8GPjWVVu5nolVIwbjd40kto_-FiQG5UnuDLBvP4n1j3/s400/exo+060+Screen+shot+2010-05-08+at+4.13.14+PM.png" id="BLOGGER_PHOTO_ID_5469041661563314690" style="cursor: pointer; display: block; height: 320px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />The shape of the Average spectrum is slightly lumpy with a mild counterclockwise skew. The previous setiQuest data sets have been mostly flat. The lumpiness and spectral skew is most likely caused by a combination of the beam steering and the off axis response of the telescope.<br /><br />Here is a list of the potentially interesting targets:</span><br />
<ul>
<li><span style="font-size: 100%;">-1681 kHz (hump) lower</span></li>
<li><span style="font-size: 100%;">-403 kHz (multiple tones)</span></li>
<li><span style="font-size: 100%;">-235 kHz (Hydrogen)</span></li>
<li><span style="font-size: 100%;">+1222 kHz (hump) upper</span></li>
</ul>
First though let us look at two data flaw characteristics; zero gaps and power fluctuation.<br />
<br />
<br />
<span style="font-size: 100%;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqI-R-0bVzHs9_m-vFAl6he9ynVuMhvpWf8-sbo389flbby6KWuNUSGsydIYrVmVKtc3LefLEt_HLs20js1iRI1-uTO6__js_dxgJmxKAl16VxcQ3Y41CY6xGkcdh8YekrwgAE/s1600/exo+060+gap+UTC+time.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqI-R-0bVzHs9_m-vFAl6he9ynVuMhvpWf8-sbo389flbby6KWuNUSGsydIYrVmVKtc3LefLEt_HLs20js1iRI1-uTO6__js_dxgJmxKAl16VxcQ3Y41CY6xGkcdh8YekrwgAE/s400/exo+060+gap+UTC+time.png" id="BLOGGER_PHOTO_ID_5469695556204192850" style="cursor: pointer; float: right; height: 59px; margin: 0pt 0pt 10px 10px; width: 280px;" /></a></span><br />
<br />
<span style="font-size: 100%;"><span style="font-size: 180%;">Zero Gaps</span><br />There is a gap of 0.057 seconds at time 03:36 from the start of the first data file. This would place it 216 seconds into the -1-of-10.dat file. The gap consists of the sample value zero. Here is a spectrogram of the gap:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDga35bENkLcDN-jwzpWlOM0QiVEYLrkhjJ5tmeRtbBs_qw1FMzyJDoe_f9ehwgN15_nQ1_6QSrJWVMFWHUznpWfTvgVj1mH9TQjT-0j28m-RHwUqeiRTS5tFH9YeKdr7In5G8/s1600/exo+060+gap+spectro.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDga35bENkLcDN-jwzpWlOM0QiVEYLrkhjJ5tmeRtbBs_qw1FMzyJDoe_f9ehwgN15_nQ1_6QSrJWVMFWHUznpWfTvgVj1mH9TQjT-0j28m-RHwUqeiRTS5tFH9YeKdr7In5G8/s400/exo+060+gap+spectro.png" id="BLOGGER_PHOTO_ID_5469695109828915794" style="cursor: pointer; display: block; height: 239px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />Here is the Waveform window at timebase=2048X zoom showing the gap:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWfrIKhkaHdt1zmQK12CXM06j0S5TtHvYEA1RlKe4CpW9YYM1GFJ99wSXjvyeOt-Bvsg1Rh0Vqc-Z7G8zGx-wFTWgV4VmGIx9LfBdy2s1oZr81G7inRJ88DkmtZJS77EGxd9Fs/s1600/exo+060+gap+waveform+2048X.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWfrIKhkaHdt1zmQK12CXM06j0S5TtHvYEA1RlKe4CpW9YYM1GFJ99wSXjvyeOt-Bvsg1Rh0Vqc-Z7G8zGx-wFTWgV4VmGIx9LfBdy2s1oZr81G7inRJ88DkmtZJS77EGxd9Fs/s400/exo+060+gap+waveform+2048X.png" id="BLOGGER_PHOTO_ID_5469695143394714226" style="cursor: pointer; display: block; height: 129px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />The beginning of the gap is visible in this Waveform window at timebase=1X zoom:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQ_emfLiwhsP70osWx2ARpQsm5-mmmSguogzKd1IlyG9aW4pb8C2-d32UrDb77ISW2fphanTeWwSnrEkk4CpNn0WgVBPdfxMkvXhpw7dkWkXmIPRAFNaPjgKAKIEgvjeh0Ke_R/s1600/exo+060+gap+waveform+1X.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQ_emfLiwhsP70osWx2ARpQsm5-mmmSguogzKd1IlyG9aW4pb8C2-d32UrDb77ISW2fphanTeWwSnrEkk4CpNn0WgVBPdfxMkvXhpw7dkWkXmIPRAFNaPjgKAKIEgvjeh0Ke_R/s400/exo+060+gap+waveform+1X.png" id="BLOGGER_PHOTO_ID_5469695132977784738" style="cursor: pointer; display: block; height: 129px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />It looks like the zero gaps start and stop abruptly and they occur numerous times throughout the 19 minute data file.<br /><br />List of zero gaps (minutes:seconds.milliseconds, gap duration seconds):</span><br />
<ul>
<li><span style="font-size: 100%;">00:25.831 - gap = 0.032s</span></li>
<li><span style="font-size: 100%;">03:36.177 - gap = 0.057s</span></li>
<li><span style="font-size: 100%;">06:50.280 - gap = 0.703s</span></li>
<li><span style="font-size: 100%;">06:59.938 - gap = 0.077s</span></li>
<li><span style="font-size: 100%;">08:00.069 - gap = 0.227s</span></li>
<li><span style="font-size: 100%;">10:55.104 - gap = 0.326s</span></li>
<li><span style="font-size: 100%;">11:16.411 - gap = 0.102s</span></li>
<li><span style="font-size: 100%;">12:16.167 - gap = 0.073s</span></li>
<li><span style="font-size: 100%;">12:31.115 - gap = 0.183s</span></li>
<li><span style="font-size: 100%;">15:00.467 - gap = 0.073s</span></li>
<li><span style="font-size: 100%;">16:00.130 - gap = 0.048s</span></li>
<li><span style="font-size: 100%;">16:30.969 - gap = 0.203s</span></li>
<li><span style="font-size: 100%;">18:25.823 - gap = 0.176s</span></li>
</ul>
<span style="font-size: 100%;">The position and the duration of the gaps seem random. These gaps are likely caused by data buffering problems in the collection equipment.<br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Power Fluctuation</span><br />Five different Average spectrum traces from different locations in the 20 GB data file are shown below:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBdUuFStD9tDYa9lR1ACzKy8a0WcxJWcXzcpeNcO4vjpQO6KRwjKOgvcjT5iES-hd1rjOFog8MVdZIgIHenwYg_E3CDEWjdCG5zUUcAUVIzS6n9-Ice75WB-hQ8D3F-oRDL8zG/s1600/Exoplanet+060+dB+fluctuation.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBdUuFStD9tDYa9lR1ACzKy8a0WcxJWcXzcpeNcO4vjpQO6KRwjKOgvcjT5iES-hd1rjOFog8MVdZIgIHenwYg_E3CDEWjdCG5zUUcAUVIzS6n9-Ice75WB-hQ8D3F-oRDL8zG/s400/Exoplanet+060+dB+fluctuation.png" id="BLOGGER_PHOTO_ID_5469024322756155842" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This represents a power fluctuation of about +1 dB. A possible source of this fluctuation could be due to the Earth's rotation changing the angle of dish collection which changes the gain. Not sure if the ATA was physically or electronically steering the dishes.<br /><br />Data was collected for the entire file using the <a href="http://baudline.com/manual/measurements.html#full">full dB power measurement</a> along with the <a href="http://baudline.com/manual/options.html#debugmeasure">-debugmeasure</a> flag to capture the numeric data for external plotting. Below is a dB vs. time graph that shows how the power fluctuates:</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhN9EzuAy82PIzgJwX24M0YGY2GQ18QjtkXL4ZzGE_od_WRbfaCdC27KexpH3vBTpbEwaEqCrZpwRMJqwY1uQLqTh8ka28w6vD9ioM5WxoNpod31KlIf0UY3YaQ7B320V2elzeW/s1600/exo060_full_dB.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhN9EzuAy82PIzgJwX24M0YGY2GQ18QjtkXL4ZzGE_od_WRbfaCdC27KexpH3vBTpbEwaEqCrZpwRMJqwY1uQLqTh8ka28w6vD9ioM5WxoNpod31KlIf0UY3YaQ7B320V2elzeW/s400/exo060_full_dB.png" id="BLOGGER_PHOTO_ID_5470963984719653474" style="cursor: pointer; display: block; height: 281px; margin: 0px auto 10px; text-align: center; width: 399px;" /></a><span style="font-size: 100%;">This plot shows a min-max delta of 0.9 dB along with 8 zero gaps. This fluctuation won't cause a problem for shorter integrations but for longer integrations the stronger sections will swamp out the weaker areas. A potential solution would be to normalize the gain with an AGC but that sort of correction will introduce other artifacts. It is best to leave the data the way it is and try to systematically avoid the problem.<br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Hydrogen has Sidebands</span><br />Hydrogen is the largest peak in the center (-235 kHz) of the Average display below:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5Y1VkDAKjciFu2i4_BH84lXnmw-wfkaAlbPmLYmw1kyW1wBctmjfo6PjJx-I5QCCgGhgeSTQMskmBVB0OdsdBYU2yvAzp4GLmmMZ-l9zWwcP5jXFDQgWp8Z6iF2KnQRTA13_W/s1600/exo+060+Hydrogen+sidebands.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5Y1VkDAKjciFu2i4_BH84lXnmw-wfkaAlbPmLYmw1kyW1wBctmjfo6PjJx-I5QCCgGhgeSTQMskmBVB0OdsdBYU2yvAzp4GLmmMZ-l9zWwcP5jXFDQgWp8Z6iF2KnQRTA13_W/s400/exo+060+Hydrogen+sidebands.png" id="BLOGGER_PHOTO_ID_5470515251523175666" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />The two small humps at -1750 and +1250 kHz are both exactly 1455 kHz away from the hydrogen peak. Another way of saying this is that the hydrogen peak is exactly in the middle of the two small humps. It appears that hydrogen has sidebands. I've never seen hydrogen have sidebands before, so this is new. There are a couple ways sidebands could of been created.<br /><br />Modulating the hydrogen peak with AM modulation at a frequency of 1455 kHz would create similar sidebands. Something modulating interstellar hydrogen seems crazy. What force could do something this cosmic? Gravitational waves or Dark Matter?<br /><br />Signal distortions can also generate sidebands. Artifacts introduced by the ATA data collection or signal processing equipment could be the source. It is difficult to know for sure without having access to the hardware and being able to run tests. An interesting clue is the sample rate of 8.738 Msamples/second divided by the sideband delta of 1.455 MHz equals 6.0055 which is close enough to the whole number six to be suspicious. <a href="http://baudline.com/manual/glossary.html#ADC">ADC</a> caused signal artifacts are often related by whole number multiples to the signal under test. The ATA's ADC is sampling at 100 * 2^20 samples/sec and being decimated by 12 so that 6 is starting to look more suspicious.<br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Hydrogen and Friends</span><br />The <a href="http://www.blogger.com/Input%20Devices">Input Devices</a> window was set to decimate by 8 and down mix into the -786 ... +307 kHz region. A +12 dB gain was used to maximize the available sample bits.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxUH4KBIMzLGYPtc4xnNdTKh5conPXQZPV2NCKaUssvpf8c1xOzFUN3R4vviQJBe1B_EijRl5tXA7cXtgdoUDKSnIh_nykNl-wWavcsgKnOmFgWWSSawiY38pV73Qo6IetAcr8/s1600/exo+060+input+devices+d8.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxUH4KBIMzLGYPtc4xnNdTKh5conPXQZPV2NCKaUssvpf8c1xOzFUN3R4vviQJBe1B_EijRl5tXA7cXtgdoUDKSnIh_nykNl-wWavcsgKnOmFgWWSSawiY38pV73Qo6IetAcr8/s400/exo+060+input+devices+d8.png" id="BLOGGER_PHOTO_ID_5469475763392482850" style="cursor: pointer; display: block; height: 400px; margin: 0px auto 10px; text-align: center; width: 390px;" /></a><br />The Average spectrum below shows hydrogen and bunch of strong tones to the left that look like distortion products.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR3Jt88pma8O4YMtlZnv93wbqvaxQ3sFivSHz6eKtKzukW6V2BzLhkKs2DXjX7dbGtM0b6Sed2WLvrVR23gcNDxRoIW6YHBy1-r0Jg9H8MPpkhMjxS4IfB-vR1TRnNmBht0gWr/s1600/exo+060+Hydrogen+%26+Friends.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR3Jt88pma8O4YMtlZnv93wbqvaxQ3sFivSHz6eKtKzukW6V2BzLhkKs2DXjX7dbGtM0b6Sed2WLvrVR23gcNDxRoIW6YHBy1-r0Jg9H8MPpkhMjxS4IfB-vR1TRnNmBht0gWr/s400/exo+060+Hydrogen+%26+Friends.png" id="BLOGGER_PHOTO_ID_5469475411955177090" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />Like in the <a href="http://baudline.blogspot.com/2010/04/setiquest-kepler-exo4-1420-mhz.html">Kepler Exo4</a> blog post, the close proximity of the multiple tones to hydrogen is interesting.<br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">-403 kHz (multiple tones)</span><br />Decimation by 32 and down mixing to the frequency of the multiple tones for a 8.333 Hz/bin resolution. The Average window shows three spectral traces from different parts of the data file. The spectrogram display shows the entire 19 minutes of data. Notice that the power fluctuations and gaps are visible. Constant and pulsing tones are also scattered across the spectrum. The spacing of the tones look like distortion products.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiroJVTmDJ8beAzqYHH3mVoPDxGfM7HpdW00X6NZ8HY-OteDWWydqI5EMtO7TX8EWc4rUw6LClhxo7NgXFcRIF0coJEMx3YDpkLmTTEbwI5Y3M-WasPhlheLP2HvP5bMKFIYLzu/s1600/exo+060+multiple-tones+full.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiroJVTmDJ8beAzqYHH3mVoPDxGfM7HpdW00X6NZ8HY-OteDWWydqI5EMtO7TX8EWc4rUw6LClhxo7NgXFcRIF0coJEMx3YDpkLmTTEbwI5Y3M-WasPhlheLP2HvP5bMKFIYLzu/s400/exo+060+multiple-tones+full.png" id="BLOGGER_PHOTO_ID_5469737737616076658" style="cursor: pointer; display: block; height: 320px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />Grouping the targets into <span style="color: #66ffff;">cyan</span>, <span style="color: #cc33cc;">magenta</span>, and <span style="color: #ffff33;">yellow</span> (CMY) color groups in the Average window:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgU-ZMqOS2OWWjcKNCRwXTVCdpvV2U355WiMSmF4nasg_1u5NugoShXWda5jZUy2nxIhA678pl9dy-V7PVtqfPdCMyXhxn1gSvdlL00vRIgCCRaC7fDlFFG6SORK4lar3lF_O97/s1600/exo+060+average+seafoam.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgU-ZMqOS2OWWjcKNCRwXTVCdpvV2U355WiMSmF4nasg_1u5NugoShXWda5jZUy2nxIhA678pl9dy-V7PVtqfPdCMyXhxn1gSvdlL00vRIgCCRaC7fDlFFG6SORK4lar3lF_O97/s400/exo+060+average+seafoam.png" id="BLOGGER_PHOTO_ID_5469822351035632002" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>The cyan, magenta, and yellow color groups look like carriers with lower and upper sidebands. The delta frequency between the carrier and the sidebands is 25600 Hz for all of the color groups. This suggests that the groups are related. AM modulating each of the carriers with a 256oo Hz sine wave is one way to create such a harmonic structure.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcukw8f4Y6VV73OBMzr4z6Gfo_zKt_oXyERS7_T-fQV8ztlZ0kWA3yVIg-U008VVQqCY5SFUl8hops_MXID2j-2kvTiLG6OipJJzRX3DB277w2EGwq8hXfMVlOKT5kHEqePORQ/s1600/exo+060+delta+Hz.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcukw8f4Y6VV73OBMzr4z6Gfo_zKt_oXyERS7_T-fQV8ztlZ0kWA3yVIg-U008VVQqCY5SFUl8hops_MXID2j-2kvTiLG6OipJJzRX3DB277w2EGwq8hXfMVlOKT5kHEqePORQ/s400/exo+060+delta+Hz.png" id="BLOGGER_PHOTO_ID_5470849006451811522" style="cursor: pointer; float: right; height: 66px; margin: 0pt 0pt 10px 10px; width: 260px;" /></a>The exact measured value is 25600.024 Hz using the <a href="http://baudline.com/manual/measurements.html#delta">delta Hz measurement</a> window. A little bit of math: ADC sample rate 100 * 2^20 / 25600 Hz = 4096. This suspicious power of 2 number suggests that these are distortion sidebands that are related to the ADC or its follow on processing. Distortion harmonics with a 25600 Hz delta were also seen in the <a href="http://baudline.blogspot.com/2010/04/setiquest-amc7-36934464-mhz.html">AMC-07</a> data.<br /><br />Here are the color groups and their center frequencies:</span><br />
<ul>
<li><span style="font-size: 100%;">Cyan -499733.3 Hz</span></li>
<li><span style="font-size: 100%;">Magenta -416316.1 Hz</span></li>
<li><span style="font-size: 100%;">Yellow -401945.2 Hz</span></li>
</ul>
<span style="font-size: 100%;">Each of the color groups will be analyzed below.<br /></span><span style="color: #66ffff; font-size: 180%;">Cyan -499733.3 Hz</span><span style="font-size: 100%;"><br />Setting the decimation to 4096 results in a 0.0651 Hz/bin resolution. Decimation gain was set to +36 dB gain so as to maximize SNR. Moving the down mixer to look at the tone at -499733.3 Hz shows a non-drifting pulsing signal. A spectrogram of the entire 19 minutes is below:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirLnYYClmY0DlgbA7IGes-6uBPKuLhMxYSFv9Z9xMdGy593z-lriOju6ZR93ZeXEEcJMdDyv-wA0zmzVYDwN1Cl1qI8QJm_DXqBaYSQ4c7jdaQuRIlyS-YEy5udrnV7JVLs9BL/s1600/exo+060+spectro+-499733Hz+d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirLnYYClmY0DlgbA7IGes-6uBPKuLhMxYSFv9Z9xMdGy593z-lriOju6ZR93ZeXEEcJMdDyv-wA0zmzVYDwN1Cl1qI8QJm_DXqBaYSQ4c7jdaQuRIlyS-YEy5udrnV7JVLs9BL/s400/exo+060+spectro+-499733Hz+d4096.png" id="BLOGGER_PHOTO_ID_5469768342037626690" style="cursor: pointer; display: block; height: 377px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>The lower and upper sidebands are about 0.54 dB down and they look identical to the carrier. This means that they are not mirror symmetric so they are not true lower and upper sidebands.<br /></span><span style="color: #cc33cc; font-size: 180%;">Magenta -416316.1 Hz</span><span style="font-size: 100%;"><br />Decimating by 4096 again while down mixing into the -416316.1 Hz tone shows a drifting random walk signal:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBp2cNU8AUISNy27v8I_Vyfo7wc2EEqZGlyTcqjfCHYidpg_kn379vMVIAHSoFfIfRXUZX9Lst-j5wJllTTnsVLhxC6Z53Tskf_kZpv27jnZQZHANgRh6mhV54rQJoDZxt4FTy/s1600/exo+060+spectro+-416316Hz+d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBp2cNU8AUISNy27v8I_Vyfo7wc2EEqZGlyTcqjfCHYidpg_kn379vMVIAHSoFfIfRXUZX9Lst-j5wJllTTnsVLhxC6Z53Tskf_kZpv27jnZQZHANgRh6mhV54rQJoDZxt4FTy/s400/exo+060+spectro+-416316Hz+d4096.png" id="BLOGGER_PHOTO_ID_5469828729130939858" style="cursor: pointer; display: block; height: 377px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />The tone starts at -416316.1 Hz and ends at -416316.1 Hz. A random walk with a drift of +8.66 Hz / 1135 seconds = +0.00763 Hz/sec. The lower and upper sidebands are about 0.7 dB down and they look identical to the carrier.<br /></span><span style="color: #ffff33; font-size: 180%;">Yellow -401945.2 Hz</span><span style="font-size: 100%;"><br />Decimating by 4096 yet again while down mixing into the -401945.2 Hz tone shows a drifting random walk signal:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYy098YMqI-D5-zWM3QCG8MoiOvGI4CLt06DcXzxBtIGpO7lPFK4oVBpbQouAHvDj930E8ReomS5hYVYNr6GU-pzi4Mj1CgD_lWFEbhJ_PZ3ujZ43DNJs2_8f6aghhMRcErbpd/s1600/exo+060+spectro+-402+kHz+d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYy098YMqI-D5-zWM3QCG8MoiOvGI4CLt06DcXzxBtIGpO7lPFK4oVBpbQouAHvDj930E8ReomS5hYVYNr6GU-pzi4Mj1CgD_lWFEbhJ_PZ3ujZ43DNJs2_8f6aghhMRcErbpd/s400/exo+060+spectro+-402+kHz+d4096.png" id="BLOGGER_PHOTO_ID_5469751181060130418" style="cursor: pointer; display: block; height: 377px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>This drifting random walks looks different than the Magenta group and it has no features in common. The tone starts at -401945.2 Hz and ends at -401935.0 Hz. A random walk with a drift of +9.8 Hz / 1135 seconds = +0.00863 Hz/sec. The maximum deviation was almost +12 Hz/sec before it wandered back to +9.8 Hz/sec where the file ended.<br /><br />The lower and upper sidebands are about 1.1 dB down and they look identical to the carrier.<br /><br /><br /><span style="font-size: 180%;">Digging in the Noise</span>Looking deeper into the noise ... searching, decimating, integrating, drifting ... finding some very weak signals.</span><span style="font-size: 100%;"> </span><span style="font-size: 100%;"> </span><span style="font-size: 100%;">Here is an annotated spectral map that shows what signals are going to be investigated and which section of spectrum is going to be zoomed:</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQYebKRgC06_o0n-9PJRpdV4fF6zW0z1r55IYhte3T4skSxcI258fBP7CvaVkxAF6_5Jr6vHg7ilh1wserOYUQBs1chy61clUw8gJgP4vZ5uI6FsdKZYlDUEo64jLzVla0rXRb/s1600/exo+060+average+seafoam2.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQYebKRgC06_o0n-9PJRpdV4fF6zW0z1r55IYhte3T4skSxcI258fBP7CvaVkxAF6_5Jr6vHg7ilh1wserOYUQBs1chy61clUw8gJgP4vZ5uI6FsdKZYlDUEo64jLzVla0rXRb/s400/exo+060+average+seafoam2.png" id="BLOGGER_PHOTO_ID_5471987847514698770" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiICN9RFxDRrii3hAgdy-hUZ_NzvWtmJkkKHmkV32vmX-ycdb0p7LJxqylBOBlaMwBkNLYg5lwbni5XgucE3z0Yux0nnpAWB6rotb-20svAioU8HPqSfevGVOrUQelsT1r19PJ/s1600/exo+060+average+seafoam3.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiICN9RFxDRrii3hAgdy-hUZ_NzvWtmJkkKHmkV32vmX-ycdb0p7LJxqylBOBlaMwBkNLYg5lwbni5XgucE3z0Yux0nnpAWB6rotb-20svAioU8HPqSfevGVOrUQelsT1r19PJ/s400/exo+060+average+seafoam3.png" id="BLOGGER_PHOTO_ID_5471997894569643938" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The <span style="color: #cc33cc;">magenta</span> and <span style="color: #ffff33;">yellow</span> dots are references for the previous carriers. The <span style="color: #ffff33;">yellow F3</span>, <span style="color: #ffcc00;">orange</span>, and <span style="color: red;">red</span> dots will be analyzed from left to right below.<span style="font-size: 100%;"> The following spectrograms used a decimation by 4096 for a 0.0651 Hz/bin resolution and</span><span style="font-size: 100%;"> the <a href="http://baudline.com/manual/process.html#auto_drift">Auto Drift</a> algorithm for additional spectrogram extraction ability (about an extra dB in this case).</span><br />
<span style="font-size: 100%;"><br /><br /><span style="font-size: 180%;"><span style="color: yellow;">-478744 Hz</span></span>Drift rate of +9.37 Hz / 1135 seconds = +0.00826 Hz/sec. This drifting-random-walk signal looks like a weaker version of Yellow </span><span style="font-size: 100%;">-401945.2 Hz. What is interesting is how far it is away from the Yellow carrier. Some math: -478744 Hz - -401945.2 Hz = -76798.8 Hz / 25600 Hz = -2.999953 which is practically 3. So this signal is the -F3 harmonic of the F0 yellow carrier.</span> The +F3 harmonic is at -325146 Hz and its spectrogram looks identical.<br />
<span style="font-size: 100%;"><br /></span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCv9j8cO37ThaVdcUAIJowhxrLh-VwHNKt6CxkvnzurPWNBrePHgR31qHSE2vwmpdRaIoBZCTPhsHDcY7Q4AyJcWCUv1jmKThLm-VpvLkCLS35SKmGakzgC9mApBtZzwfhfsgX/s1600/exo+060+spectro+-478744Hz_d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCv9j8cO37ThaVdcUAIJowhxrLh-VwHNKt6CxkvnzurPWNBrePHgR31qHSE2vwmpdRaIoBZCTPhsHDcY7Q4AyJcWCUv1jmKThLm-VpvLkCLS35SKmGakzgC9mApBtZzwfhfsgX/s400/exo+060+spectro+-478744Hz_d4096.png" id="BLOGGER_PHOTO_ID_5471568151926188770" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
<span style="font-size: 180%;"><br />-422933.3 Hz</span>Vertical pulsing signal directly in the middle of the spectrogram. Drift rate is 0.0 Hz/sec. This signal is extremely interesting and it will be demodulated in the Advanced Analysis section below.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiX7UKcMs7zfQe85IYpBaYnSF5tMXt1K3u8KlqA09AY_pvXEbDyBcnd27weAOktJjsMfo7ZBWzg-cZTcchd7rA5652o3VEhtn68GsKP-gB-bEJlEHFWQ2I5fC_hxHjME54U2ABp/s1600/exo+060+spectro+-422933.3Hz_d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiX7UKcMs7zfQe85IYpBaYnSF5tMXt1K3u8KlqA09AY_pvXEbDyBcnd27weAOktJjsMfo7ZBWzg-cZTcchd7rA5652o3VEhtn68GsKP-gB-bEJlEHFWQ2I5fC_hxHjME54U2ABp/s400/exo+060+spectro+-422933.3Hz_d4096.png" id="BLOGGER_PHOTO_ID_5471857436605542594" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
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<span style="font-size: 100%;"><span style="color: #ffcc00; font-size: 180%;">-415089 Hz</span><br />Orange. Interesting cyclic random walk signal. The spectrogram of the carrier harmonics at plus and minus 25600 Hz look identical but weaker. </span><span style="font-size: 100%;">Drift rate of +11.78 Hz / 1135 seconds = +0.01038 Hz/sec.</span><br />
<span style="font-size: 100%;"><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwR7VwPLgde6RwAQYXgh3gL1iezvpcK5HHup6rd8QbB2WDaPpxGtAFTKje2S0KqQM3tbI909csNybNKR6hEVUxOZXWPbW8uPXdlQJQG1jiK4awBMvvHRWaEb_GCM3LN1pIu37U/s1600/exo+060+spectro+-415089Hz_d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwR7VwPLgde6RwAQYXgh3gL1iezvpcK5HHup6rd8QbB2WDaPpxGtAFTKje2S0KqQM3tbI909csNybNKR6hEVUxOZXWPbW8uPXdlQJQG1jiK4awBMvvHRWaEb_GCM3LN1pIu37U/s400/exo+060+spectro+-415089Hz_d4096.png" id="BLOGGER_PHOTO_ID_5470488302412189874" style="cursor: pointer; display: block; height: 377px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br /><br /><span style="font-size: 180%;">-409252 Hz</span>An extremely weak random walking signal that has about twice the frequency swing of the previous cyclic signal. This signal is pushing the limits of what can be visually detected in the current version of the baudline software. </span><span style="font-size: 100%;">Drift rate of +7.16 Hz / 1135 seconds = +0.00631 Hz/sec.</span><br />
<span style="font-size: 100%;"><br /></span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXowGfCBCxPrRiWTTv-OBIRXCMrensgx74fCVaRyhMz8nZjhZtjKjuqH26AE8frLdzLrWEXq0MPwHv-7yWo1cCCsb2ZFYvPjsis6SDAieDhDr1vwkkx_tmvCiyqeA64mO2PQZ0/s1600/exo+060+spectro+-409252Hz_d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXowGfCBCxPrRiWTTv-OBIRXCMrensgx74fCVaRyhMz8nZjhZtjKjuqH26AE8frLdzLrWEXq0MPwHv-7yWo1cCCsb2ZFYvPjsis6SDAieDhDr1vwkkx_tmvCiyqeA64mO2PQZ0/s400/exo+060+spectro+-409252Hz_d4096.png" id="BLOGGER_PHOTO_ID_5471288154514276242" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
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<span style="font-size: 100%;"><span style="font-size: 180%;">-407416 Hz</span></span>A random walk that disappears just before the 700 second position which equates to the 438 seconds from the start of the data. There are several zero gaps and a large power fluctuation discontinuity at this position. The signal disappears into the noise as the total system power continues to decrease. The signal becomes visible again near the end as the system power increases. This an excellent example of the signal detection problem created by the fluctuating power.<br />
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<span style="font-size: 100%;">Drift rate of +12.63 Hz / 1135 seconds = +0.01113 Hz/sec.</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEib4LHTguxlCI1tEFEHjgYVqCFunZ4e8vWo52g6WF2fQpv0GVRfC9i-NYXCqUdaXgGxs1Fpu-Y-Hcd9EV6eTVFsfHgf-kLxLWutIJRWXAl4kaE_n7Ir_b0KnfQQynsjroet151-/s1600/exo+060+spectro+-407416Hz_d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEib4LHTguxlCI1tEFEHjgYVqCFunZ4e8vWo52g6WF2fQpv0GVRfC9i-NYXCqUdaXgGxs1Fpu-Y-Hcd9EV6eTVFsfHgf-kLxLWutIJRWXAl4kaE_n7Ir_b0KnfQQynsjroet151-/s400/exo+060+spectro+-407416Hz_d4096.png" id="BLOGGER_PHOTO_ID_5471284608875460226" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
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<span style="font-size: 100%;"><span style="font-size: 180%;">-406250 Hz</span></span>Drifting random walk with a drift rate of -0.98 Hz / <span style="font-size: 100%;"> 1135 seconds = </span>-0.00086 Hz/sec. This signal is interesting because it is the first negative drift rate.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZjH-Z9JeWxOIizGSWLh3mBU7iV0eBN40LUxKlTWfdN5Nrl6aJHUkTuv7Twtj8vouIJo-USxy_o1aC2ly5cIq2-hbNNS70WzqsMR89HSX4RWx2kYlo4eP8eeekvRM5f-xwv0Nd/s1600/exo+060+spectro+-406250Hz_d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZjH-Z9JeWxOIizGSWLh3mBU7iV0eBN40LUxKlTWfdN5Nrl6aJHUkTuv7Twtj8vouIJo-USxy_o1aC2ly5cIq2-hbNNS70WzqsMR89HSX4RWx2kYlo4eP8eeekvRM5f-xwv0Nd/s400/exo+060+spectro+-406250Hz_d4096.png" id="BLOGGER_PHOTO_ID_5471278389882209154" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
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<span style="font-size: 180%;">-400943 Hz</span>Very wide sweep, had to change spectrogram zoom to Hz=2X. Delta drift of -16.2 Hz / 1135 seconds = -0.0143 Hz/sec but the initial swing was almost -50 Hz. The shape of this signal looks a lot like the curve in the Power Fluctuation plot but with time reversed. There is no logical reasoning for this similarity but it is an oddity worth pointing out.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsnpsrr5QPbywzWlkCFxmKHSNJF8SDKGpVoICE2uuh7nnP5xXUjPXOwUshReXEYNgMMtOaP7R4zs0cC0P6b8Tzb751kJ3-VTcsIWzET2AdpT12r8nk2u03OULjHPPjXXTl73Jv/s1600/exo+060+spectro+-400943Hz_d4096.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsnpsrr5QPbywzWlkCFxmKHSNJF8SDKGpVoICE2uuh7nnP5xXUjPXOwUshReXEYNgMMtOaP7R4zs0cC0P6b8Tzb751kJ3-VTcsIWzET2AdpT12r8nk2u03OULjHPPjXXTl73Jv/s400/exo+060+spectro+-400943Hz_d4096.png" id="BLOGGER_PHOTO_ID_5471670407700857202" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
<span style="font-weight: bold;">Exercise for the reader:</span> For the orange -415089 Hz signal and the -400943 Hz signal above, assume the basic curve shape was caused by Doppler drift applied to a narrowband signal. Describe the motion that would cause this drift. For bonus points calculate the required velocities. Feel free to discuss this in the comments below.<br />
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<span style="font-size: 100%;"><span style="font-size: 180%;">Advanced Analysis</span>What other hidden signal characteristics are lurking in this Exoplanet 060 data file? We will answer that question in this section by demonstrating how some of baudline's more sophisticated tools work. Autocorrelation, cross-correlation, demodulation, blip Fourier phase, quadrature magnitude, transfer function, impulse responses, and Auto Drift will all be explored.<br /><br /><br /><span style="font-size: 180%;">Demodulation</span></span><span style="font-size: 100%;">In this section we will attempt to demodulate the <span style="color: #66ffff;">cyan</span><span style="color: #66ffff;"> -499733.3 Hz</span> signal that was discussed above. This non-drifting signal signal is most likely of terrestrial origin but nevertheless it has some very interesting structure. We have re-downmixed the </span><span style="font-size: 100%;">-499733.3 Hz signal and decimated it by a total factor of 1048576 for a 0.01526 Hz/bin resolution. </span>Below is the Fourier spectrogram:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdxL0lqkhGyyGplemPjEcKqnSzRJhHd7tjkLmyp7MUR5cKMa9CG9WXJ9CA6440VglwhrtaTVLsuPgB5cIBbUQrQWLw1sUCnh0HnH2PwQsNIOife0tcnB_gljsUJxCF3mqvnu-T/s1600/exo_060_d1048576_-499733.35Hz.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdxL0lqkhGyyGplemPjEcKqnSzRJhHd7tjkLmyp7MUR5cKMa9CG9WXJ9CA6440VglwhrtaTVLsuPgB5cIBbUQrQWLw1sUCnh0HnH2PwQsNIOife0tcnB_gljsUJxCF3mqvnu-T/s400/exo_060_d1048576_-499733.35Hz.png" id="BLOGGER_PHOTO_ID_5474249128889542434" style="cursor: pointer; display: block; height: 364px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Even at this additional magnification the signal appears to have zero drift. A pulsing pattern is visible but there appears that there might be something more going on with the signal. Let us zoom in a little for more a closer look. We will be decimating by 4194304 for a 0.00381 Hz/bin resolution.<br />
<span style="font-size: 100%;"><br />Click this Average display image for a larger version:</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh64jWivg5qAElcO0Shmz8XU4PmzqeMI95YbAG8jyszdVgRMwcU7y-unomZ7Vgi9h-HZMDG4T_LWb1eeXJFUDiXKu0kdPhsKWM8k2PD3PBoV-wm3Lq5hlHHAOm6puJPRPnXHumP/s1600/exo_060_d4194304_-499733.35Hz_avg.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh64jWivg5qAElcO0Shmz8XU4PmzqeMI95YbAG8jyszdVgRMwcU7y-unomZ7Vgi9h-HZMDG4T_LWb1eeXJFUDiXKu0kdPhsKWM8k2PD3PBoV-wm3Lq5hlHHAOm6puJPRPnXHumP/s400/exo_060_d4194304_-499733.35Hz_avg.png" id="BLOGGER_PHOTO_ID_5474281445703032018" style="cursor: pointer; display: block; height: 156px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
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This looks a lot like a strange sort of Multiple Frequency Shift Key (MFSK) with an extra tone off to the side. Here are the frequencies of the 4 tones { 2000.0114, 2000.0691, 2000.1068, 2000.1605 } Hz. Calculating the deltas between the frequencies {0.0577, 0.0377, 0.0537 } Hz which appears very non-uniform. Grouping similar looking peaks; the delta between the first and third is 0.0954 Hz while the delta between the second and forth peaks is 0.0914 Hz. The forth off-to-the-side tone has a unique distinction of being -4 dB down from the others and spectrally isolated.<br />
<span style="font-size: 100%;"><br />Due to the extreme nature of the magnification we will be using the <span style="font-weight: bold;">blip Fourier</span> transform to improve the visual resolution for the next two spectrograms. Here is the blip magnitude spectrogram:</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjez_yFMRZGXNdiGRAna_1xgwVRAiq97Fdsa0_xVLhNk79YmbHwyTzqXLUyiC7TdGotmmgP4EzBHr9lLxkLT6dqeUUa0YJSzTAdyDVaQP92m8TPc4RRV90OCmE5a_wyDn2AfFsn/s1600/exo_060_d4194304_-499733.35Hz_mag_g.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjez_yFMRZGXNdiGRAna_1xgwVRAiq97Fdsa0_xVLhNk79YmbHwyTzqXLUyiC7TdGotmmgP4EzBHr9lLxkLT6dqeUUa0YJSzTAdyDVaQP92m8TPc4RRV90OCmE5a_wyDn2AfFsn/s400/exo_060_d4194304_-499733.35Hz_mag_g.png" id="BLOGGER_PHOTO_ID_5474267669108167906" style="cursor: pointer; display: block; height: 335px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The multiple frequencies toggling on and off create shapes that seem to have some structure. Using baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> reveals a baud rate that varies between 18 - 24 seconds (0.056 - 0.042 baud). The symbol spacing appears periodic but its non-constant rate is troubling.<br />
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For a change of perspective let's rotate the modulated structure counterclockwise 90 degrees:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgptL937LjB9CXBy2m60I932rknzmFsuw-CcN108w9Oiy-Uex879eas95AjXA8zfzFHMRWyQz_CZKjjvxWkxd8ySGJnAF7H34Rn1vevje-qZTqCUqarT3GCYhXQbcFSZIMpRYFF/s1600/exo_060_blip_mag_rotated.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgptL937LjB9CXBy2m60I932rknzmFsuw-CcN108w9Oiy-Uex879eas95AjXA8zfzFHMRWyQz_CZKjjvxWkxd8ySGJnAF7H34Rn1vevje-qZTqCUqarT3GCYhXQbcFSZIMpRYFF/s400/exo_060_blip_mag_rotated.png" id="BLOGGER_PHOTO_ID_5474566069193127922" style="cursor: pointer; display: block; height: 70px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
<span style="font-size: 100%;">Next, let us see if looking at phase space tells us anything more. Here is the blip phase spectrogram:</span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT_DcztbnkO1J2eqNRTUsxBiY6OKe4JGmVolupc3Mv6fu7iYqD48KopzWQUGIGuVtm8R7Ryy90BNHyIyX-QyR0xrB4mGEp9n4wlc154xWP1SBbm12ZvBLlsxAaE4DN19oDvyK_/s1600/exo_060_d4194304_-499733.35Hz_phase.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT_DcztbnkO1J2eqNRTUsxBiY6OKe4JGmVolupc3Mv6fu7iYqD48KopzWQUGIGuVtm8R7Ryy90BNHyIyX-QyR0xrB4mGEp9n4wlc154xWP1SBbm12ZvBLlsxAaE4DN19oDvyK_/s400/exo_060_d4194304_-499733.35Hz_phase.png" id="BLOGGER_PHOTO_ID_5474268642798262754" style="cursor: pointer; display: block; height: 335px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>Several abrupt phase changes are visible. They appear during some of the longer duration symbol patterns which suggest some form of mixed frequency and phase coding like Orthogonal frequency-division multiplexing (OFDM). This is very different than the phase changes of the drifting-random-walk FSK signal observed in the <a href="http://baudline.blogspot.com/2010/04/setiquest-kepler-exo4-1420-mhz.html">Kepler Exo4</a> analysis.<br />
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Next let us try looking at this strangely modulated signal with the Autocorrelation transform. Think of the horizontal spectrogram slices as time-domain waveform plots that have been automatically time slip corrected for the variable baud rate. The pulses (beats) represent individual symbols and the patterns created are how the symbol relationship change over time.<br />
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Autocorrelation with a square window shows the relative global viewpoint:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7g5GNAEHdQL4swHEAQ5bcSytQgcjbBBCMHojcpNHH5JN4pnOQFbLorApNdCeKytrDwAzaw7oRlIaClS0KomAa3d6EHcdzS6zbQQi0r-UwRLIka8RueffmImlAnr7DEf42uJTY/s1600/exo_060_d4194304_-499733.35Hz_auto2.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7g5GNAEHdQL4swHEAQ5bcSytQgcjbBBCMHojcpNHH5JN4pnOQFbLorApNdCeKytrDwAzaw7oRlIaClS0KomAa3d6EHcdzS6zbQQi0r-UwRLIka8RueffmImlAnr7DEf42uJTY/s400/exo_060_d4194304_-499733.35Hz_auto2.png" id="BLOGGER_PHOTO_ID_5474553821276618658" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Autocorrelation with a Kaiser window beta=40. shows the relative local viewpoint:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_ldiFGmIGw-Rw-0egdFskMCJ6nwo0ppjgIgt9-vP93-J_m85b3VU7nquZ9i-wNTS_YvrJNoAANJ3u9_yN-DJyaqlmZpxTNs8_7QfalDuO7Kv5ULP7xYcfaGA4-6j6-zRV8v8z/s1600/exo_060_d4194304_-499733.35Hz_auto1.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_ldiFGmIGw-Rw-0egdFskMCJ6nwo0ppjgIgt9-vP93-J_m85b3VU7nquZ9i-wNTS_YvrJNoAANJ3u9_yN-DJyaqlmZpxTNs8_7QfalDuO7Kv5ULP7xYcfaGA4-6j6-zRV8v8z/s400/exo_060_d4194304_-499733.35Hz_auto1.png" id="BLOGGER_PHOTO_ID_5474553495689753714" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The two Autocorrelations show that both the global and local structures have complicated symbol relationships. Demodulation could use these Autocorrelation plots to help determine exact symbol transition (baud) points.<br />
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More demodulation TBD.<br />
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<span style="font-size: 100%;"><br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Auto Drift</span></span><span style="font-size: 100%;">A Doppler drifting signal spreads out its energy across the spectrum as it moves. This makes detection of drifting signals much more difficult. <a href="http://baudline.com/manual/process.html#auto_drift">Auto drift</a> is an algorithm that searches all of the possible linear drifting paths for the correct solution.</span> It works in the Spectrogram and Average displays. It operates in both of baudline's Record and Pause modes. It has multiple controls, adjustable parameters, and algorithms. It is very CPU and memory intensive. It is also extremely powerful at pulling weak drifting signals out of the noise.<br />
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Below are two screenshots of the Average display. The first is the plain Fourier transform of a familiar chunk of spectrum. The second is the Fourier (green) overlayed with the Auto Drift (purple) spectrum.<br />
<span style="font-size: 100%;"><br /></span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5on2fo1OFDmMQGJxsGMZySbWXkLMrMZqu-89IP4HiEUiSy067-ngl7fl8NPUL1UDcXKSzGdD1VqgymA1wgJ9odtVt6o1xRVdyOJAEyJGprqFIPRWyjJ72BG4ChqJrGZTC44Je/s1600/exo+060+advanced+Fourier.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5on2fo1OFDmMQGJxsGMZySbWXkLMrMZqu-89IP4HiEUiSy067-ngl7fl8NPUL1UDcXKSzGdD1VqgymA1wgJ9odtVt6o1xRVdyOJAEyJGprqFIPRWyjJ72BG4ChqJrGZTC44Je/s400/exo+060+advanced+Fourier.png" id="BLOGGER_PHOTO_ID_5473480457671586722" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEil66NZx2Lyh3CNOnfFalwMuo-yzum7T9ne1PF_QBjhdoGKdNUqQEZo6qyDjs56YGWwifL7T7s_SqUB1eQ5giCAHXDawo6GLEf3LMwe5cgAVx20C8hFFiX9OBhsEwsRmIJUy8yF/s1600/exo+060+advanced+Auto+Drift.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEil66NZx2Lyh3CNOnfFalwMuo-yzum7T9ne1PF_QBjhdoGKdNUqQEZo6qyDjs56YGWwifL7T7s_SqUB1eQ5giCAHXDawo6GLEf3LMwe5cgAVx20C8hFFiX9OBhsEwsRmIJUy8yF/s400/exo+060+advanced+Auto+Drift.png" id="BLOGGER_PHOTO_ID_5473480721705692722" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Notice how Auto Drift increased the strength of the two biggest peaks by 2+ dB. Another interesting observation is that the Auto Drift's noise floor increased while it's variance was reduced. All of the linear drifting signals got a boost equal to or greater than the increase in the noise floor while the amplitude of the stationary signals did not. This spectral display could be used to quickly determine which signals are drifting. The two purple dots represent weak signals that the Auto Drift algorithm discovered. Let's zoom in and get a closer look:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhTK1_rXd2yc1KcWf70C5ILNl30gYdPqMt2AnsAGb-i9fB1O0HKuveSlHFNMFYJM6dfotyAm82ptiZ8v2melgQAm9jQP8ZwRzMsURL8gEDw_iV_rzJKgx4tbEG-DbMz1dFfEWE/s1600/exo+060+advanced+Auto+Drift+zoom.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhTK1_rXd2yc1KcWf70C5ILNl30gYdPqMt2AnsAGb-i9fB1O0HKuveSlHFNMFYJM6dfotyAm82ptiZ8v2melgQAm9jQP8ZwRzMsURL8gEDw_iV_rzJKgx4tbEG-DbMz1dFfEWE/s400/exo+060+advanced+Auto+Drift+zoom.png" id="BLOGGER_PHOTO_ID_5473481805808096338" style="cursor: pointer; display: block; height: 142px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The two purple dot signals at -410768 Hz and -409577 Hz were not there before. To further explore the two purple dots we will be zooming into the frequency domain by decimating by 4096 and using the Auto Drift algorithm in the spectrogram display for a little more signal extraction. Let us look at the first -410768 Hz signal:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizgziwiYfEkiSKfVMLCWH75Zk96anwaxbH24qSgvQaDLzuUvE7UoiVLkgxLPewU93DDsuHFrsbUQmhEt8CwYznBKOtJFtKmiS_FEC85V47c_viPSz_QL_HUIz-oduxW-DAvc35/s1600/exo+060+advanced+Auto+Drift+-410849Hz.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizgziwiYfEkiSKfVMLCWH75Zk96anwaxbH24qSgvQaDLzuUvE7UoiVLkgxLPewU93DDsuHFrsbUQmhEt8CwYznBKOtJFtKmiS_FEC85V47c_viPSz_QL_HUIz-oduxW-DAvc35/s400/exo+060+advanced+Auto+Drift+-410849Hz.png" id="BLOGGER_PHOTO_ID_5473482545882797954" style="cursor: pointer; display: block; height: 376px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The frequency zoom was increased to Hz=4X so that the quickly drifting signal would fit on the spectrogram display. <span style="font-size: 100%;">This signal has a slight random walk with a drift of +68.5 Hz / 1135 seconds = +0.0604 Hz/sec.</span> This is much faster than we've seen in the previous sections.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0JAoKdmV239VYU3f1jtdWuuunr3OWvw-UfsbqAYd6HD21OSsfjQutHCF4CLUvHPcb4QaBJzjjkj68IZSv4ClblW-xfeHiERgUnq_NJIKenIPQ4lNkQLi3BdR9D5nacF9vVHgS/s1600/exo+060+advanced+Auto+Drift+measurement.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0JAoKdmV239VYU3f1jtdWuuunr3OWvw-UfsbqAYd6HD21OSsfjQutHCF4CLUvHPcb4QaBJzjjkj68IZSv4ClblW-xfeHiERgUnq_NJIKenIPQ4lNkQLi3BdR9D5nacF9vVHgS/s400/exo+060+advanced+Auto+Drift+measurement.png" id="BLOGGER_PHOTO_ID_5473495232095840258" style="cursor: pointer; float: right; height: 66px; margin: 0pt 0pt 10px 10px; width: 260px;" /></a>We can use the <a href="http://baudline.com/manual/measurements.html#auto_drift_rate">auto drift rate measurement</a> window to query the Auto Drift solutions on a peak-by-peak basis. To do this you'll need to set the source to Average and the fundamental rule to one of the mousing modes. Next you just move the mouse over the peaks in the Average display to get that particular Hz/s drift rate. Note that this also works with the spectrogram/spectrum while recording. Auto Drift quality control can have an effect on the resolution granularity. It is interesting the Auto Drift solution used a +0.0552 Hz/sec drift rate while above we measured a +0.0604 Hz/sec drift rate by hand. The reason for this disparity isn't human measurement error or algorithm quality granularity. What Auto Drift did is calculate a solution using a different path, a more optimal path. Look at the spectrogram with a straight edge, compare the two paths, and you'll see that the algorithm was correct.<br />
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Next let us look at the -409577 Hz signal:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT4R0AlRaemXOD_48EypSEq-CozUNNLz6LrwyjiZc8O1AIgArimSdZfcyrsjiW-UmOhCvRRstFZhoBvgM4iopdPtEpaG9vzulfzGXH7hR9LGL5sVbtMrJ1t-hbnKHoXTak-hSa/s1600/exo+060+Hz%3D32X+dB%3D48X.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjT4R0AlRaemXOD_48EypSEq-CozUNNLz6LrwyjiZc8O1AIgArimSdZfcyrsjiW-UmOhCvRRstFZhoBvgM4iopdPtEpaG9vzulfzGXH7hR9LGL5sVbtMrJ1t-hbnKHoXTak-hSa/s400/exo+060+Hz%3D32X+dB%3D48X.png" id="BLOGGER_PHOTO_ID_5473833984247258130" style="cursor: pointer; display: block; height: 149px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The auto drift rate measurement says that the peak beneath the purple dot is drifting at -0.0191 Hz/sec. Note that the stronger signal to the right is -209252 Hz that was investigated above in the Digging in the Noise section. The spectrogram below has been zoomed into the frequency range represented by the purple dot centered at -409577 Hz.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjh5q7D2QKuNWAlJ_c2WFiwhSIbt-pyPEGnhoIRHUNgriLMBa3NXHsdDVX4oWKzZa6_sYLWan9rvkDOMReQUuAxp4UdaBbhCH99EesVmHkBvBlPSE6SEgQtIiVKHXDJh2BiHLN5/s1600/exo+060+advanced+Auto+Drift+-409577Hz.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjh5q7D2QKuNWAlJ_c2WFiwhSIbt-pyPEGnhoIRHUNgriLMBa3NXHsdDVX4oWKzZa6_sYLWan9rvkDOMReQUuAxp4UdaBbhCH99EesVmHkBvBlPSE6SEgQtIiVKHXDJh2BiHLN5/s400/exo+060+advanced+Auto+Drift+-409577Hz.png" id="BLOGGER_PHOTO_ID_5473798065431598594" style="cursor: pointer; display: block; height: 382px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
Do you see the signal? I don't but I do see several clumps of brighter than usual blips. According to Auto Drift the linear path solution has a drift rate of -0.0191 Hz/sec which starts at -409555 Hz and ends at -409577 Hz. The signal path is not obvious in this view so let us look at a Hz zoomed in version of the Average display:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrLHbJgV3K4RgfEARMqZ0ruXR6WMVVURdCNvs6M2Ppa89tesbZBfQsiL63bYcdlYKqlS-Pq3YTtVSDEjsDcROrZ3baPQZ0kwTy-M2o7CkIA2zDopEG8EbMqr-OQ0eMGO54e4c1/s1600/exo+060+Hz%3D1X+dB%3D48X.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrLHbJgV3K4RgfEARMqZ0ruXR6WMVVURdCNvs6M2Ppa89tesbZBfQsiL63bYcdlYKqlS-Pq3YTtVSDEjsDcROrZ3baPQZ0kwTy-M2o7CkIA2zDopEG8EbMqr-OQ0eMGO54e4c1/s400/exo+060+Hz%3D1X+dB%3D48X.png" id="BLOGGER_PHOTO_ID_5473837631355898866" style="cursor: pointer; display: block; height: 148px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The Auto Drift solution has been spread out. The seven purple dots have drift rates of { -0.0304, -0.0291, -0.0278, -0.0255, -0.0274, -0.0219, -0.0191 } Hz/sec. Notice that the drift rates are slowly decreasing from left to right. The normal fluctuation of drift rates is random in the positive and negative directions. The seven purple dots are clearly related and suggest the actual drift had a curved non-linear shape.<br />
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Next let us take a look at the inner workings of Auto Drift. Behind the scenes so-to-speak. Beams slices were set to 218 seconds and the auto drift quality was set to 6. Baudline dynamically allocated a 1.3 gigabyte buffer to calculate this spectrogram:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0wafmTLGa21WRcNMCKm1sVv0pGsCWKhaOYfaIHcPwdgia_Z1VP0Kmth5tiamwXAFp6PrzM323T33xkNA2Ht21iyuGeaVqfBMfEYFDYI0yvpSpLQ0yC8bTJuUGwPEQOATrJ5ID/s1600/exo+060+Auto+Drift+quality%3D6.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0wafmTLGa21WRcNMCKm1sVv0pGsCWKhaOYfaIHcPwdgia_Z1VP0Kmth5tiamwXAFp6PrzM323T33xkNA2Ht21iyuGeaVqfBMfEYFDYI0yvpSpLQ0yC8bTJuUGwPEQOATrJ5ID/s400/exo+060+Auto+Drift+quality%3D6.png" id="BLOGGER_PHOTO_ID_5473813633579837922" style="cursor: pointer; display: block; height: 382px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a>Click the image above for a higher resolution version and see the fine structure detail. That spectrogram image is made up of 10.2 billion drift vectors. The black region at the top is working space because of the large beam slices used and should be ignored. The spectrogram intensity begins to fade about half way down and then gets stronger near the end. This tracks the Power Fluctuation plot perfectly and it causes numerous integrating problems due to mismatch in spectral levels as a function of time. Auto Drift performance would of been better with a constant power envelope. The main feature of interest in this spectrogram plot is the detailed structure created by all of the drift vectors.<br />
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Drift vectors are going every which direction but there is a prominence of drift vectors traveling from right to left in the middle frequency section of the spectrogram. This corresponds to what we saw for the Auto Drift plot when we zoomed in the Average display. That is, a clumping of vector solutions with a general -0.02 to -0.03 Hz/sec drift rate scattered over a constrained frequency region. This suggests that our weak signal is a random-walk that is under going a slightly curved drift. Further analysis and more advanced techniques are required to better understand this drifting weak signal.<br />
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<span style="font-size: 180%;">Invisible Elephants</span><br />
Something enormous is lurking in this data file. Set baudline's Input Mapping <a href="http://baudline.com/manual/channel_mapping.html#operation">time domain operation</a> to quadrature <span style="font-weight: bold;">magnitude</span> to see the Fourier power envelope. Now you see it but more importantly it sees you! Eek! Run!<br />
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The green spectral plot is a Fourier transform of the Q channel. That little hump near 250 kHz is hydrogen. The purple spectral plot is the Fourier transform of the quadrature magnitude time-domain operation. Both of these are plotted below in the Average window for a sense of scale.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDha6wmSGnRzLKCvtuYly1hBDQougPgxQq1Os-KxsCMGlc3WLGkeysqBnen4quSSPN7FgI2Lif6bIIWSJurPA7Bms1aECSQBEZEYeZA1kcN0Nu74QU2JexIcSz6lSSZqe8Tvxz/s1600/+exo+060+elephants+mag+65536.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDha6wmSGnRzLKCvtuYly1hBDQougPgxQq1Os-KxsCMGlc3WLGkeysqBnen4quSSPN7FgI2Lif6bIIWSJurPA7Bms1aECSQBEZEYeZA1kcN0Nu74QU2JexIcSz6lSSZqe8Tvxz/s400/+exo+060+elephants+mag+65536.png" id="BLOGGER_PHOTO_ID_5474649382049448210" style="cursor: pointer; display: block; height: 155px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The elephants are the three large purple spikes that happen to be at exactly 1/3 and 2/3 and 3/3 the Nyquist frequency. The two elephants at 1/3 and 2/3 also have 25600 Hz sidebands. The 2/3's elephant also has 76800 Hz sidebands. The third elephant at 3/3 is only partially visible because is peeking around the Nyquist folding frequency. The frequency of the 1/3 elephant matches the spacing of Hydrogen's Sidebands that was discussed above.<br />
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The smaller purple spikes on the right side are 25600 Hz and 11+ of its harmonics.<br />
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The large purple spikes are artifacts or distortion products from a quadrature DSP math bug in either the ATA beamformer or decimator. My guess would be an error in the decimator because the base ATA 100 Msample/sec rate is decimated by 12 and the elephants are at multiples of 1/3. A third is a difficult error to generate by accident unless you happen to be doing something at a multiple of that such as decimate by 12 = 3 * 4.<br />
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I have theory on the source of the 25600 Hz harmonics and sidebands. [Elaborate on this more TBD]<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtVOTA6wZhOit3ozldIwDp5jrGfjHfJUTDL2GqUHnQaXaxakT0jnmDLGhZ-qAIoZBCdXHkXhGemskdgYhZQvKniGaM9nG7V5QI2oM2t9Z4pIrDgo_U9ABASMm-U8zowOFfDPN1/s1600/polka_dotted_elephant.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtVOTA6wZhOit3ozldIwDp5jrGfjHfJUTDL2GqUHnQaXaxakT0jnmDLGhZ-qAIoZBCdXHkXhGemskdgYhZQvKniGaM9nG7V5QI2oM2t9Z4pIrDgo_U9ABASMm-U8zowOFfDPN1/s200/polka_dotted_elephant.jpg" id="BLOGGER_PHOTO_ID_5474921945845013234" style="cursor: pointer; float: right; height: 77px; margin: 0pt 0pt 10px 10px; width: 94px;" /></a>Now something extremely interesting happens when you decimate this signal by 2 or by 4. The biggest 2/3 elephant is still there at 2/3 Nyquist. Things get even stranger when the down mixer frequency is moved and the 2/3 elephant stays stationary! I mean it doesn't move on the spectral display. This is analogous to changing the tuner on your radio and every station is playing the same polka song! And your radio isn't broken either. Decimating by 8 makes the elephant go away. This may seem paradoxically mind-bending but it is just a unique form of phase distortion. There is actually a lot more to it than that. Bonus points to anyone who emails me the correct amusing and magical technical word that describes this phenomena!<br />
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Next, a look at 60 Hz by using the quadrature magnitude operation with the Fourier transform and decimating by 256 for a 0.5208 Hz/bin resolution.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF78_3JETpaTo1hdX0_HBesuu8HoM-4p7JoohCmeYKcT1v4hzMnCQ2RcRFaupMvVsdznnfVmoxqe0jgrsJ8aXvaeLgutWi4XzXuvkhbCylMCkETA2zgCkC7rUgKLGJykivOoKR/s1600/+exo+060+elephants+60+Hz.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF78_3JETpaTo1hdX0_HBesuu8HoM-4p7JoohCmeYKcT1v4hzMnCQ2RcRFaupMvVsdznnfVmoxqe0jgrsJ8aXvaeLgutWi4XzXuvkhbCylMCkETA2zgCkC7rUgKLGJykivOoKR/s400/+exo+060+elephants+60+Hz.png" id="BLOGGER_PHOTO_ID_5475302794938453490" style="cursor: pointer; display: block; height: 155px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The three tones are at 59.882, 119.760, and 179.663 Hz. So this is 60 Hz AC line bleed-in and two of its harmonics. Upon further analysis two unusual things happen. This signal gets weaker as you decimate and it is visible down to decimation by 8192. Also, when the down mixer frequency is changed these tones remain stationary. They are smaller this time but the elephants are back.<br />
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<span style="font-size: 180%;">Filter Extraction</span><br />
The filter is a basic DSP primitive that is used in things like quadrature, decimators, and the FFT. Basically everything is a filter. By using the transfer function and impulse response transforms information about the internal workings of a system or device can be deduced without any a priori knowledge. This is extremely powerful.<br />
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Here is a transfer function of phase space between the I and Q channels. Note that the vertical axis is phase and should have units of radians or degrees.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIrpeYK8TWYo5YTvaRMH1pQRcckowdLG5eTPrMkF5qUt7ofaZQEsl_L2ktUjgIFELRuDfk2mzKCgsW2NI1dAUhBeYR_mwemCIpSsT-whLc9cqP5cZsJJ-Sckdn6sAmsqZR9Z2y/s1600/+exo+060+elephants+phase+65536.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIrpeYK8TWYo5YTvaRMH1pQRcckowdLG5eTPrMkF5qUt7ofaZQEsl_L2ktUjgIFELRuDfk2mzKCgsW2NI1dAUhBeYR_mwemCIpSsT-whLc9cqP5cZsJJ-Sckdn6sAmsqZR9Z2y/s400/+exo+060+elephants+phase+65536.png" id="BLOGGER_PHOTO_ID_5474661547958888754" style="cursor: pointer; display: block; height: 155px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
The peak at 230.4 kHz represents at 0.031 radian or a 5.6 degree phase shift. Now the question is is this an artifact or is it just a side effect of the quadrature coding? It is interesting that the phase slowly decreases as frequency increases. The phase rise on the right side is likely due to the decimation filters.<br />
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The impulse response transform was used to compare the I and Q channels. It should be noted that because of the stimulus source being very white noise-like the cross-correlation produces a similar image. Note that the horizontal axis should be time lag (not Hz) and the vertical axis should be a linear scale (not dB).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEie8TRF-QQny8_g8lFHw_GupuYbsXV1RHT3LJmol8w2pFO_XqJqD3pOaSjpCBeXIZPvXfa4KEogEQa-Rj6r3hkfUkn2_LMSr-d9tZA-gjIS6gReoRO6N3vIlu8eebdHGbyn0muE/s1600/+exo+060+elephants+impulse+2048.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEie8TRF-QQny8_g8lFHw_GupuYbsXV1RHT3LJmol8w2pFO_XqJqD3pOaSjpCBeXIZPvXfa4KEogEQa-Rj6r3hkfUkn2_LMSr-d9tZA-gjIS6gReoRO6N3vIlu8eebdHGbyn0muE/s400/+exo+060+elephants+impulse+2048.png" id="BLOGGER_PHOTO_ID_5474666959572704450" style="cursor: pointer; display: block; height: 155px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
This impulse response shape is fascinating. It looks like a Hilbert FIR filter in the center mixed with a larger LPF FIR filter. The inverted phase on one side matches the symmetry of a Hilbert filter and isn't surprising since we are looking at the impulse response between the quadrature I & Q channels. The next image attempts to remove the quadrature element by applying the Hilbert filter to the I channel prior to calculating the impulse response. From the filter's perspective this effectively undoes quadrature.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPUUirlG-XN0_oBNO71VPv0_BtDO4h0u2HWcbpHIGkeMjZo5KYxL1KCdMRsKJWHnDV_hwceMeYn_b_96sLu5O4fYOyaupU11jZKjXrE0J0badQ_kuVHpL8qA0PfN0JG2kQRegx/s1600/+exo+060+elephants+impulse+2048+hilbert.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPUUirlG-XN0_oBNO71VPv0_BtDO4h0u2HWcbpHIGkeMjZo5KYxL1KCdMRsKJWHnDV_hwceMeYn_b_96sLu5O4fYOyaupU11jZKjXrE0J0badQ_kuVHpL8qA0PfN0JG2kQRegx/s400/+exo+060+elephants+impulse+2048+hilbert.png" id="BLOGGER_PHOTO_ID_5475268836355180066" style="cursor: pointer; display: block; height: 155px; margin: 0px auto 10px; text-align: center; width: 400px;" /></a><br />
What we are looking at is what I believe to be the filter shape for the WOLA-FFT decimating filter bank that the ATA is using. It is a sum of two filters; a larger 160 tap wrapped WOLA filter construct and a smaller 16 point FFT filter bank.<br />
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In this advanced analysis section we learned that there are many DSP techniques that can be used to find hidden and elusive signals. We learned that when distortions enter the data they can manifest themselves in ways and places that are very unexpected. We also learned that DSP can be used as a tool to peer inside a device and understand how it works just by looking at the output data.<br />
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<span style="font-size: 100%;"><br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Listen</span>links to sound files or a demonstration video?<br /><br />more TBD<br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Conclusion</span></span><span style="font-size: 100%;">The 20 GB (19 minutes) of data took a lot of CPU cycles and a long time to analyze. I need access to a faster computer with more RAM to run some of the algorithms I would like. Remote access to an 8+ core, 16+ GB RAM machine would be very helpful. </span><span style="font-size: 100%;">Baudline works great remotely with X11 tunneled through SSH.</span> No modifications would be required. Now on to the signal analysis.<br />
<span style="font-size: 100%;"><br /></span><span style="font-size: 100%;">First the good news. The signals in the CMY color groups contain one pulsing and two drifting-random-walking signals that have interesting characteristics. Plus there is much weaker family of signals, the first is -415098 Hz, which so far also appears to be very interesting. These signals don't seem to be related other than their close proximity to Hydrogen. An important question is why are there so many seemingly unrelated drifting-random-walking signals? More analysis is necessary and this blog will be updated as that happens.<br /><br />Now for the bad. The 19 minutes of Exoplanet 060 data contain many flaws:</span><br />
<ul>
<li><span style="font-size: 100%;">Power fluctuations of almost 1 dB.</span></li>
<li><span style="font-size: 100%;">13 zero gaps of duration 0.03 - 0.70 seconds occur randomly.</span></li>
<li><span style="font-size: 100%;">Hydrogen has sidebands that are 1455 kHz away.</span></li>
<li><span style="font-size: 100%;">CMY color groups have sidebands that are 25600 Hz away.</span></li>
</ul>
<span style="font-size: 100%;">The power fluctuations and zero gaps will make accurate long duration integrations difficult. This will hurt weak signal detection. Hydrogen has sidebands which at first appeared to be an amazing scientific discovery. Then I did some math: 8.738 MS/s / 1.455 MHz = 6.0055 which is very close to the whole number 6. The base ADC rate is being decimated by 12 so now Hydrogen's sidebands seem very suspicious. The sidebands of the CMY color groups also have a very suspicious mathematical relationship involving the ADC sample rate: 100 * 2^20 / 25600 Hz = 4096.<br /><br />I believe the 4 flaws are not related which means there are 4 separate error sources in the ATA's signal chain, but that is just a guess. I mention that the sidebands could be caused by AM modulation but distortions in the complex domain data path could also cause them. These will likely be tricky bugs to fix. My recommendation is that the ATA should hire the contract and consulting firm <a href="http://sigblips.com/">SigBlips DSP engineering</a> to fix these problems. SigBlips has extensive expertise in the real-time, DSP, and Unix disciplines which is an ideal combination for this set of problems.<br /></span><span style="font-size: 100%;"><span style="font-size: 180%;">Links</span></span><br />
<ul>
<li><span style="font-size: 100%;"><a href="http://setiquest.org/forum/topic/baudline-analysis-exoplanet-060">http://setiquest.org/forum/topic/baudline-analysis-exoplanet-060</a></span></li>
</ul>
<span style="font-size: 100%;"><br /></span>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com6tag:blogger.com,1999:blog-19780926.post-65350857970269840502010-05-11T10:24:00.000-07:002011-02-22T16:21:18.623-08:00setiQuest tutorial<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMS5e3NWb5TLaeqv-E5et1ekEIKpwrpbwWR7ccsr5hBTE_cQhdu5iP5eXxVaSNsIKLCvYvC6ETUASOK7bTW0IbpHK5S7Jad0HSUM9INekJysEY4J0hCSgF5VPXEWmtfCDNwqDj/s1600/setiQuest_logo.gif" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470069245483905858" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMS5e3NWb5TLaeqv-E5et1ekEIKpwrpbwWR7ccsr5hBTE_cQhdu5iP5eXxVaSNsIKLCvYvC6ETUASOK7bTW0IbpHK5S7Jad0HSUM9INekJysEY4J0hCSgF5VPXEWmtfCDNwqDj/s400/setiQuest_logo.gif" style="cursor: pointer; float: right; height: 44px; margin: 0pt 0pt 10px 10px; width: 171px;" border="0" /></a>The <a href="http://www.setiquest.org/">setiQuest</a> project was spawned by <a href="http://www.tedprize.org/jill-tarter/">Jill Tarter's TED wish</a> and is sponsored by the <a href="http://www.seti.org/">SETI Institute</a>. The goal is to empower "Earthlings" all over the planet to help in the Search for Extraterrestrial Intelligence. Their plan to do this is by allowing access to data collected from the Allen Telescope Array (ATA) and by releasing their source code sometime in Q3 2010. Access to the data was made available in April 2010. Source code is great but the true value of setiQuest comes from access to the data.<br /><br />Today you can use the <a href="http://www.baudline.com/">baudline signal analyzer</a> to explore the setiQuest data. To get access to the data you'll first need to <a href="http://setiquest.org/user/register">register</a> for a free setiQuest user account. Next you will need to feed the data into baudline and that is the purpose of this tutorial.<br /><br />There are two ways to get the setiQuest <a href="http://baudline.com/manual/options.html#quadrature">quadrature</a> .dat files into baudline. One is to read them in as a raw data file. The other is to stream them into baudline's standard input (<a href="http://baudline.com/manual/options.html#stdin">stdin</a>) which is like recording from a microphone but instead using a Unix pipe construct.<br /><br /><br /><span style="font-size:180%;"><b style="font-weight: normal;">raw data file</b></span><br />First thing you'll want to do is set the <a href="http://baudline.com/manual/equalization.html#transform_size">FFT size</a> to 65536 since these are weak signals. Second, set the <a href="http://baudline.com/manual/open_file.html#open_file">Open File</a> window to use the Raw format and then select and open your data file. Next, set the <a href="http://baudline.com/manual/open_file.html#raw_parameters">Raw Parameters</a> to the appropriate 8-bit quadrature format. Here is a screenshot of the proper setiQuest raw parameters:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgp9wNk8hiXJx_MhUl9-Xk-FuLfQ6Q3o5yeX-buP0pv45BudyC3RGPvhE3MIiSkH-fD62-aba-4uBejPQ2dYovXmEZagodKDIepZsbSwCjwn9CCcw2Z5T2lUFiQlMYla1h8kXMV/s1600/setiquest_raw_parameters.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470067950619933762" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgp9wNk8hiXJx_MhUl9-Xk-FuLfQ6Q3o5yeX-buP0pv45BudyC3RGPvhE3MIiSkH-fD62-aba-4uBejPQ2dYovXmEZagodKDIepZsbSwCjwn9CCcw2Z5T2lUFiQlMYla1h8kXMV/s400/setiquest_raw_parameters.png" style="cursor: pointer; display: block; height: 299px; margin: 0px auto 10px; text-align: center; width: 400px;" border="0" /></a><br />Large data files are going to cause problems because baudline is basically a big RAM based buffer. You will need a lot of RAM and even then they will be clamped at a 2 GB limit. So opening in raw mode is good for small files but very bad for huge files.<br /><br /><br /><span style="font-size:180%;"><b style="font-weight: normal;">stdin</b></span><br />This is the preferred method. Stream the .dat file(s) into baudline using the Unix standard input. This way you can record and pause just as if you had access to the live ATA data stream (as if it was a soundcard). With files and <a href="http://baudline.com/manual/options.html#stdin">stdin</a> you can process data at the speed you want and at the speed your computer can handle. Fast enough computers can actually record and have scrolling baudline spectrograms in real-time (8.7 MS/s quadrature). Here is a sample command line I use to stream setiQuest data into baudline:<br /><br /><span class="Apple-style-span"><span class="Apple-style-span" style="font-size:small;">cat 2010-01-22-kepler-exo4-1420mhz.dat | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133 -fftsize 65536 -pause -utc 0<br /></span></span><br />Here is a typical screenshot:<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdI9cF5kOyhFhaoe4DOETvQtd18XrsV1LfG324oYYeJYKzUWWrpBOLJ9XTf74XoAMhgvggMPrPJFiVfgbCIUdmK0-9JH_LZ-pKTaiIKf6BxlD_JVIeBCpBenhaCpDgpu-5cF4G/s1600/amc7-3693.4464.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5463055837259377762" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdI9cF5kOyhFhaoe4DOETvQtd18XrsV1LfG324oYYeJYKzUWWrpBOLJ9XTf74XoAMhgvggMPrPJFiVfgbCIUdmK0-9JH_LZ-pKTaiIKf6BxlD_JVIeBCpBenhaCpDgpu-5cF4G/s400/amc7-3693.4464.png" style="cursor: pointer; display: block; height: 320px; margin: 0px auto 10px; text-align: center; width: 400px;" border="0" /></a><br />The large green window is the <a href="http://baudline.com/manual/display.html#spectrogram">spectrogram display</a> with frequency across the horizontal axis and time on the vertical axis. Vertical lines are constant tones. Sometimes you will see signals moving around in the spectrogram display; pulsing, drifting, wandering, ... The spectrogram display can be scrolled, zoomed, and controlled in numerous other ways.<br /><br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXaIjySj8Qbd5Jzh0gB6W7OmMrfEhAoFgrp4Yj4xMvkJLdbGtugnx2k5fhGn2yBWov-vuWHXSzfUX8aD-W2XlKo5qCwe8psJzYrylyT6NS7D6hobhNVEKv2-C2jkNXsTaRvSGr/s1600/main_popup.gif" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470090244681431922" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXaIjySj8Qbd5Jzh0gB6W7OmMrfEhAoFgrp4Yj4xMvkJLdbGtugnx2k5fhGn2yBWov-vuWHXSzfUX8aD-W2XlKo5qCwe8psJzYrylyT6NS7D6hobhNVEKv2-C2jkNXsTaRvSGr/s400/main_popup.gif" style="cursor: pointer; float: right; height: 216px; margin: 0pt 0pt 10px 10px; width: 123px;" border="0" /></a><span style="font-size:180%;">Record, Pause, and Play</span><br />Use the 3rd mouse button (right button or Command+button) to popup the main menu and select between Record and Pause modes. You can also do this with the controls from the <a href="http://baudline.com/manual/play_deck.html#play_deck">Play Deck</a>. The idea is to record and watch the spectrogram scroll by and then pause it if you see something interesting or if you would like to perform some zooming, scrolling, measuring, or additional analysis.<br /><br />Baudline has many features that can be used to analyze the data. Remember that the full power of baudline is accessed through the main popup menu. Some of baudline's many other windows have popup menus too.<br /><br /><br /><span style="font-size:180%;">Decimate and Down Mix</span><br />The <a href="http://baudline.com/manual/input.html#input_devices">Input Devices</a> window is used for selecting the sound card and it also works with standard input. The Decimate By and the Down Mixer controls will allow you to zoom into the frequency spectrum much like how a radio tuner works. Decimation adjusts the sample rate so think of it as a way to change how wide a chunk of frequency you want to look at. Decimation is a great way to increase SNR similar to increasing the FFT size. The Down Mixer selects the frequency to look at just like a tuner dial on a radio.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRGvgyZCQgMe7kAlx8BtcBWUmVzEiyYbtVDD1PDYgl537noCdyQ3yKe_VBF_zfyXdYIYZMklqaPY3eddXI31iuMv-gIZ53uvQVqjqITQ1s6KcMA_dlAQgrUgz2jZnzmKmrbrtL/s1600/input+devices+stdin+DDC.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470102482745274034" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRGvgyZCQgMe7kAlx8BtcBWUmVzEiyYbtVDD1PDYgl537noCdyQ3yKe_VBF_zfyXdYIYZMklqaPY3eddXI31iuMv-gIZ53uvQVqjqITQ1s6KcMA_dlAQgrUgz2jZnzmKmrbrtL/s400/input+devices+stdin+DDC.png" style="cursor: pointer; display: block; height: 400px; margin: 0px auto 10px; text-align: center; width: 390px;" border="0" /></a>These controls only work while in the record mode on the incoming data stream. So you can make changes while recording but if you want to change the entire data stream from the beginning you will have make the adjustment, exit baudline which will save your <a href="http://baudline.com/manual/options.html#session">session</a> settings, and then restart baudline from the command line.<br /><br />I like running several instances of baudline with the same stdin data stream all at the same time. Setting decimation to none will give you the full width of the spectrum. I like doing this as a first pass and keep it around as a map for a second instance of baudline on another screen. I decimate and down mix in that second instance of baudline. Sometimes I have up to ten baudlines open at a time doing different things, managing memory usage is important when I do this.<br /><br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf-0pi6HfzsB1W3Nt8MGqHrlHVLUapoj9a05hiKjbvjnwEwHeqt1kesrQ8pViaS_2eqd0xOK3MeXI0XrfIwSG3iZU7sp83Ob6nPDYLeEUNrmr-b6xlw7qYslmopZ7N5SU4SZbV/s1600/scroll+control.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470134824702691282" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf-0pi6HfzsB1W3Nt8MGqHrlHVLUapoj9a05hiKjbvjnwEwHeqt1kesrQ8pViaS_2eqd0xOK3MeXI0XrfIwSG3iZU7sp83Ob6nPDYLeEUNrmr-b6xlw7qYslmopZ7N5SU4SZbV/s400/scroll+control.png" style="cursor: pointer; float: right; height: 371px; margin: 0pt 0pt 10px 10px; width: 153px;" border="0" /></a><span style="font-size:180%;">Scroll Control</span><br />As its name implies, the <a href="http://baudline.com/manua/color_picker.html#scroll_control">Scroll Control</a> window is how you control scrolling and manage memory. Baudline is basically a big wrap-around buffer and with this Scroll Control window you control the overlap value, the maximum capture time, and the amount of RAM to dedicate to buffer space.<br /><br />The overlap setting adjusts the recording mode's scrolling speed. Fast on the left and slow on the right. Don't use it to change the size of the spectrogram image, instead use the timebase zoom controls for that. For setiQuest data I recommend setting the overlap to its maximum 1.0 value. This will let you collect the longest duration of data in the buffer. It will also slow the scrolling rate down so that your computer can better keep up with a real-time stream.<br /><br />The buffers (MB) slider allows you set the maximum amount of RAM in megabytes that you want baudline to use. Big buffers allow for collecting large amounts of data and for fast timebase spectrogram zooming but they take up a lot of space. Too much RAM allocated means less is available to other applications and the operating system. When RAM gets low things can get slow when memory starts getting swapped to disk. My advice is to use a large buffer when you need to collect a lot of data or for a long time. Use smaller buffers for things like when you decimate by 4096.<br /><br />The Reallocate Now button will erase all the current data in and reallocate the buffers according to your new overlap and MB settings. Pressing this button will also update the Maximum Capture Time value. Use this button with caution.<br /><br /><br /><span style="font-size:180%;">Color Aperture</span><br />Weak signals have very little dynamic range so the <a href="http://baudline.com/manual/color_picker.html#color_aperture">Color Aperture</a> window is a way to control spectrogram intensity.<br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyDrEcqUiXZfPQ0nsrF5DCJTK33xVCE5pe0ZT_WdbSDQpEAUvTmy2VN5edX9eUWFIYakrDmrxRB77v4pJZnukVharsGN_zrHcI3lHqY86ZghzIA41aJpcndj5GeeF2XvCfddfl/s1600/color+aperture.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470103985001019282" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyDrEcqUiXZfPQ0nsrF5DCJTK33xVCE5pe0ZT_WdbSDQpEAUvTmy2VN5edX9eUWFIYakrDmrxRB77v4pJZnukVharsGN_zrHcI3lHqY86ZghzIA41aJpcndj5GeeF2XvCfddfl/s400/color+aperture.png" style="cursor: pointer; display: block; height: 239px; margin: 0px auto 10px; text-align: center; width: 283px;" border="0" /></a>Adjust the upper and lower dB values to match you signal's spectral range and maximize your color resolution. Heavily averaged (integrated) signals have a lower variance so the upper and lower controls can be set much closer together without the color clipping.<br /><br /><br /><span style="font-size:180%;">Average Spectrum</span><br />The <a href="http://baudline.com/manual/average.html#average">Average</a> window allows you to integrate (average) a large number of spectral slices. Spectral integration reduces the variance of the noise floor which is useful for seeing weak signals. Zooming into the Hz and dB axis is also very useful for seeing weak signal details.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg02UATyTdOgBnQTe3VqZySyx2TmZcsRcUZgr_XOytKDE5gBg206i9z1ed8-3RHEUbSv2p-CAvv9EtpnevtbcVw2uQGmRKQPb4dIsr32NUKMyEy7nD4YkOgaR5QNQXpkrhC9ZXH/s1600/kepler-exo4+average+zoom+2.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470105468702524818" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg02UATyTdOgBnQTe3VqZySyx2TmZcsRcUZgr_XOytKDE5gBg206i9z1ed8-3RHEUbSv2p-CAvv9EtpnevtbcVw2uQGmRKQPb4dIsr32NUKMyEy7nD4YkOgaR5QNQXpkrhC9ZXH/s400/kepler-exo4+average+zoom+2.png" style="cursor: pointer; display: block; height: 172px; margin: 0px auto 10px; text-align: center; width: 400px;" border="0" /></a><br />The Average window operates in the record mode by the on/off collecting of data and in the pause mode by copy-n-pasting chunks of data. The Average window has a number of other useful features such as multiple color spectral traces (F# banks) and exponential decay while recording. These controls are accessed by the Average window's popup menu (3rd mouse button).<br /><br /><br /><span style="font-size:180%;">Histogram</span><br />The <a href="http://baudline.com/manual/histogram.html#histogram">Histogram</a> display shows the probability distribution of a waveform's sample amplitudes. The setiQuest data is predominantly noise that has a Gaussian shaped distribution (bell shaped curve). The unusual example histogram below shows the basic Gaussian shape with an offset between the I (green) and Q (purple) quadrature channels.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeXb-YMVYv9kGTV4Qm8bBR4NAI2Q6dEJUvvzfI503LYdfLozajw8LJ2hrKqvZHD7Eu6lH1HpOL5OnD1mtc53hlZA5T5u6yUNAltMA6wmYy2Sl_wnnVwwXzKeY2uubF2R9hjadA/s1600/kepler04-3+-2422400Hz++histogram3.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 145px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeXb-YMVYv9kGTV4Qm8bBR4NAI2Q6dEJUvvzfI503LYdfLozajw8LJ2hrKqvZHD7Eu6lH1HpOL5OnD1mtc53hlZA5T5u6yUNAltMA6wmYy2Sl_wnnVwwXzKeY2uubF2R9hjadA/s400/kepler04-3+-2422400Hz++histogram3.png" alt="" id="BLOGGER_PHOTO_ID_5576663726116122818" border="0" /></a>Normally the I/Q channels are perfectly balanced and all that is visible is a clean Gaussian shape that is the color cyan which is the sum of green and purple. Here is another Histogram window example that shows distribution gaps due to the signed 8-bit quantized samples. Note that 2^8 = 256 samples.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjo1opfOtAS3AZyjXtkIklRo_tbeWFPIHkDk-vk5A-KpIAO8AA1Fv3qtVI5DmiAsYC7VBSEJZApy0mpBYtAER0jIDPWNUsqA2TFOygVnSB88oOjWJFoWm5gIqrMSPpAnO5_wDEb/s1600/histogram+8-bit+gaps.png"><img style="display: block; margin: 0px auto 10px; text-align: center; cursor: pointer; width: 400px; height: 153px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjo1opfOtAS3AZyjXtkIklRo_tbeWFPIHkDk-vk5A-KpIAO8AA1Fv3qtVI5DmiAsYC7VBSEJZApy0mpBYtAER0jIDPWNUsqA2TFOygVnSB88oOjWJFoWm5gIqrMSPpAnO5_wDEb/s400/histogram+8-bit+gaps.png" alt="" id="BLOGGER_PHOTO_ID_5576669680075016994" border="0" /></a>The Histogram window is useful for seeing certain types of signal distortions and collection artifacts but it is <span style="font-weight: bold;">not</span> useful as a weak signal analysis tool.<br /><br /><br /><span style="font-size:180%;">Drift Integrator</span><br />The <a href="http://baudline.com/manual/process.html#drift_integrator">Drift Integrator</a> window is a powerful but more complicated set of controls for all things integration related. The beam width control is like averaging for the spectrogram display. The drift rate and Auto Drift controls are tightly coupled to both the Average window and the Spectrogram display.<br /><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgX-njf3lkbAPSQwIoQ-SSEhkKMhBpSb8xaWxf1JGTB6GZNXgrVBGEvGgBUn3QGDNCHc9UuRdRuppfcrloklgHEHWEsNH2PHOvf1wAIzfSicutZSw2d5Mf8arOcj5KAnLrSxch5/s1600/drift+integrator.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" id="BLOGGER_PHOTO_ID_5470105592861616146" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgX-njf3lkbAPSQwIoQ-SSEhkKMhBpSb8xaWxf1JGTB6GZNXgrVBGEvGgBUn3QGDNCHc9UuRdRuppfcrloklgHEHWEsNH2PHOvf1wAIzfSicutZSw2d5Mf8arOcj5KAnLrSxch5/s400/drift+integrator.png" style="cursor: pointer; display: block; height: 400px; margin: 0px auto 10px; text-align: center; width: 267px;" border="0" /></a>I recommend setting the "anti-alias on spectrogram zoom" setting as it will dynamically improve your spectrogram image when you zoom out. The rest of the Drift Integrator settings have a great deal of potential for SETI but they are slightly dangerous so they are for experts only. Read the <a href="http://baudline.com/manual/index.html">online manual</a> and become an expert!<br /><br /><br /><span style="font-size:180%;">More</span><br />I've tried to make the setiQuest <a href="http://baudline.blogspot.com/2010/04/setiquest-amc7-36934464-mhz.html">AMC-07</a> and the <a href="http://baudline.blogspot.com/2010/04/setiquest-kepler-exo4-1420-mhz.html">Kepler Exoplanet 4</a> blog posts as educational / tutorial-like as I can while still reporting useful analysis. I describe all the details and settings that I used so anyone should be able to reproduce my results. Many baudline tips and DSP techniques are hidden within too. I hope you find them helpful.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1tag:blogger.com,1999:blog-19780926.post-55688974776463246702010-04-24T14:01:00.000-07:002010-09-28T08:34:08.926-07:00setiQuest Kepler-Exo4 1420 MHzThis analysis is of the <a href="http://setiquest.org/">setiQuest</a> Kepler Exoplanet 4 data file with the <a href="http://www.baudline.com/">baudline signal analyzer.</a> The quadrature data file has a base frequency of 1419.4464 MHz and a sample rate of 8.738133 Msamples per second. Not much information is given about this data file but I assume it is an observation of the <a href="http://en.wikipedia.org/wiki/Kepler_Mission">Kepler Mission satellite</a> collected at the Allen Telescope Array. But the SNR is far too low to be the telemetry of a near Earth satellite so the signal source could be the Kepler-4 planet (KIC 11853905). Will need source confirmation from the SETI Institute since they collected the signal. In any case there is some interesting stuff happening in this data file.<br /><br />The following command line was used to stream the Kepler Exoplanet 4 data file into baudline:<br /><br /><span style="font-size:85%;"><span style="font-family:courier new;">cat 2010-01-22-kepler-exo4-1420mhz.dat | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133 -fftsize 65536 -pause -utc 0</span></span><br /><br /><span style="font-size:180%;">Full 8.738 MHz view</span><br />The Kelper Exo4 file was streamed into baudline's standard input. A 65536 point FFT was used for a bin resolution of 266.667 Hz / bin. The Welch window was used for a little more signal extraction SNR. The Histogram window shows a nice Gaussian noise shape with even-odd holes for the 8-bit samples. Optimal anti-alias beam slices were used to smooth the spectrogram and the Color Aperture window was tweaked to maximize the color resolution. Only 50 seconds of the spectrogram are shown because the run was RAM limited. The red Average spectrum shows a hump and 6 strong tones.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgc9-OQCYM8P67m7CaexgnDx22YFsSmeqoA_DPjr5MwEn-TckYoqFO4ijifzQtA8TlHcXPjpFcXZHYTlhdnDUM9-uoPS_OrGM23jt85SDvNR_9XXpTRxDtMTgQbm6gTqWKglwBg/s1600/kepler-exo4+d1.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgc9-OQCYM8P67m7CaexgnDx22YFsSmeqoA_DPjr5MwEn-TckYoqFO4ijifzQtA8TlHcXPjpFcXZHYTlhdnDUM9-uoPS_OrGM23jt85SDvNR_9XXpTRxDtMTgQbm6gTqWKglwBg/s400/kepler-exo4+d1.png" alt="" id="BLOGGER_PHOTO_ID_5463916298413800754" border="0" /></a><br />From the spectrogram; the two strongest features are the stationary tone at -3874 kHz and the spectral hump at 1000 kHz. Looking at the red Average plot shows several more sharp tones. Here is a list of the potentially interesting targets, add 1419.4464 MHz base frequency:<br /><ul><li>-3868800 Hz - very strong - stationary<br /></li><li>-3470933 Hz - strong - random walk - drift<br /></li><li>-2713067 Hz - weak - wild random walk - drift<br /></li><li>-1482667 Hz - strong - wild random walk - drift</li><li>+586133 Hz - strong - drift - extremely interesting - "friend"<br /></li><li>+977867 Hz in hump - weak - wild random walk - drift</li><li>+900000 ... +1111000 Hz (hump) - hydrogen - see below<br /></li></ul>All of these candidate signals are investigated individually below. Decimating by 4096 to increase the extraction power was used for all of them expect the hydrogen hump. Most of the analysis is quickly skimmed over except for the most interesting +586133 Hz signal which is analyzed at the end.<br /><br /><br /><span style="font-size:180%;">Hydrogen and Friend</span><br />Zooming the Average window into the frequency axis reveals this strong tone and spectral hump. Tone and hump, they make an interesting pair.<br /><br /><span style="text-decoration: underline;"></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCnS1NsDprW23a77gZUTfj0it_Dn4EJaNU4bunhvPa-R3PmHH3rX4kL3B4_Kk7L4oO-ap-8iVYXCkV4TqEXDFYUtOwTN4Yu9ZcCGbG4lqIkEsv1ix0HuL8kDs1XysTH7zPMbSt/s1600/kepler-exo4+average+zoom+2.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 172px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCnS1NsDprW23a77gZUTfj0it_Dn4EJaNU4bunhvPa-R3PmHH3rX4kL3B4_Kk7L4oO-ap-8iVYXCkV4TqEXDFYUtOwTN4Yu9ZcCGbG4lqIkEsv1ix0HuL8kDs1XysTH7zPMbSt/s400/kepler-exo4+average+zoom+2.png" alt="" id="BLOGGER_PHOTO_ID_5463919390164901170" border="0" /></a><br />The spectral hump at +1 MHz is hydrogen. Interstellar hydrogen in space emits radio frequencies at 1.42 GHz, so with the base frequency offset the hump is centered at around 1.421 GHz. The strong tone to the left is just outside the "water hole" and because it requires a much more detailed analysis we will investigate it last.<br /><br /><br /><span style="font-size:180%;">-3868800 Hz</span><br />Decimating by 4096. Very strong stationary tone in the filter roll-off skirt. No drift. Not interesting.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdRuAhppz8COUYHFBQzLwz5zhUQ-JTqYHYHT9wb9CTAhtHC4IU93dIN8g-C7eaL0WaUzRV6soGvAdPyTJwQzOnlr0v7riM-1Lj-9zpmMwqp-VRld9-ACcg2UVfru_OZTvHWNJg/s1600/kepler-exo4+-3868800+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 271px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdRuAhppz8COUYHFBQzLwz5zhUQ-JTqYHYHT9wb9CTAhtHC4IU93dIN8g-C7eaL0WaUzRV6soGvAdPyTJwQzOnlr0v7riM-1Lj-9zpmMwqp-VRld9-ACcg2UVfru_OZTvHWNJg/s400/kepler-exo4+-3868800+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5463981103775176354" border="0" /></a><br /><br /><span style="font-size:180%;">-3470933 Hz</span><br />Decimating by 4096. Random walk tone with positive slope drift. +29 Hz drift / 326 seconds = +0.089 Hz / sec.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7Y_qJ8kfRlXNaT-MXsHuhAzdjC69s5vZU_xjHTrXjYgh8oGKM5K9jSE79jvPSWPaba-acHhiqC8XhgTwIvcVJ6c76H9Bex-oi8w2WkGzeop41971j6J69oLgfwN4UtTrsWHAu/s1600/kepler-exo4+-3470940+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 271px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7Y_qJ8kfRlXNaT-MXsHuhAzdjC69s5vZU_xjHTrXjYgh8oGKM5K9jSE79jvPSWPaba-acHhiqC8XhgTwIvcVJ6c76H9Bex-oi8w2WkGzeop41971j6J69oLgfwN4UtTrsWHAu/s400/kepler-exo4+-3470940+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5463981575275628706" border="0" /></a><br /><br /><span style="font-size:180%;">-2713067 Hz</span><br />Decimating by 4096. Random walk tone with positive slope drift. Difficult to measure, roughly +29 Hz drift / 326 seconds = +0.089 Hz / sec. It looks a bit like the previous signal but it is much weaker and it appears to be jumping around more. It could be a sideband of something but it doesn't seem to be harmonically related to the previous tone. More decimation might help pull out more signal.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3NR7KJpCBYCX7m1CdLWymO2CsiWvTCr1BLvsmu2_tJDPxturDzvmds-n-6j6fFyrt-d6ch8Rn9dnhnhDqCnYJLTvZNUPjRCtMwYhRIuzi6jhgC60hKP0wlBsy7i95EM36t_0z/s1600/kepler-exo4+-2713067+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 271px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3NR7KJpCBYCX7m1CdLWymO2CsiWvTCr1BLvsmu2_tJDPxturDzvmds-n-6j6fFyrt-d6ch8Rn9dnhnhDqCnYJLTvZNUPjRCtMwYhRIuzi6jhgC60hKP0wlBsy7i95EM36t_0z/s400/kepler-exo4+-2713067+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5463986779175495586" border="0" /></a><br /><br /><span style="font-size:180%;">-1482667 Hz</span><br />Decimating by 4096. Random walk tone with positive slope drift. Difficult to measure, roughly +29 Hz drift / 326 seconds = +0.089 Hz / sec. Looks almost exactly like a stronger version of the above signal.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheIaMHCCrR8Yi4siUctX5VcPTisWNgIb0DUlfH8fRFa1TiAGUJxp7sEo1I5MsUPSN85GOZ-B6UgMHib_3A3W915yWZbbfC5_goK7MqIqXMN5oU_c0TT2bI1tMdbD6NnzF4KZVB/s1600/kepler-exo4+-1482667+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 271px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheIaMHCCrR8Yi4siUctX5VcPTisWNgIb0DUlfH8fRFa1TiAGUJxp7sEo1I5MsUPSN85GOZ-B6UgMHib_3A3W915yWZbbfC5_goK7MqIqXMN5oU_c0TT2bI1tMdbD6NnzF4KZVB/s400/kepler-exo4+-1482667+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5463991696333807826" border="0" /></a><br /><br /><span style="font-size:180%;">+977867 Hz</span><br />Decimating by 4096. This signal is the weak tone that is in the hydrogen hump mentioned above. Very weak version of the above signal. Strength and random wander are almost identical to the -2713067 Hz signal. Why this signal is in the hydrogen hump is unknown.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDYUWtSnzk2nyVnXDq_klGjUv1AD7aB0sdz_ru0YP_-kTiLXFSKyzEw9AHy_VYSV33mrsGGPNQX1f3A7HY_HvQ7gf8Y-aJIQ4QiU0E023iz4OJE4uKLL65JqxkrI9g3NFIfgUs/s1600/kepler-exo4+%2B977867+Hz.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 271px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDYUWtSnzk2nyVnXDq_klGjUv1AD7aB0sdz_ru0YP_-kTiLXFSKyzEw9AHy_VYSV33mrsGGPNQX1f3A7HY_HvQ7gf8Y-aJIQ4QiU0E023iz4OJE4uKLL65JqxkrI9g3NFIfgUs/s400/kepler-exo4+%2B977867+Hz.png" alt="" id="BLOGGER_PHOTO_ID_5463995080796188370" border="0" /></a>This and the previous two signals are virtual copies of each other. They do not appear to be harmonically related. They could be sidebands or distortion products of the strong stationary tone but the harmonic relationship doesn't seem correct.<br /><br /><br /><span style="font-size:180%;">+586133 Hz</span><br />"Hydrogen's friend." This signal is extremely interesting. The true frequency of this tone is 1420.586133 MHz and it is just to the left of the hydrogen spectral hump. To zoom into the +586223 Hz tone the Input Devices window was set to decimate by 4096 with a +30 dB gain to improve the quantization SNR.<sup>1</sup> The down mixer was set to a center frequency of +586133.3 Hz. The 4096 decimation along with a 65536 point FFT resulted in a bin resolution of 0.0651 Hz / bin.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHMaG6VA1t7cOjxrNKMZu8vjrZBMxfv7Ri_B5Gg1Okeu3zfTK4VbQcs5zsm5DOWHp1ULvm_DN5Uz60dDs2ovH7TTKEpJWQXxMrb7dhBbSyZEIvY-oNHcDbZYK23x6yD_6xw54U/s1600/kepler-exo4+input+devices+d4096.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 390px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHMaG6VA1t7cOjxrNKMZu8vjrZBMxfv7Ri_B5Gg1Okeu3zfTK4VbQcs5zsm5DOWHp1ULvm_DN5Uz60dDs2ovH7TTKEpJWQXxMrb7dhBbSyZEIvY-oNHcDbZYK23x6yD_6xw54U/s400/kepler-exo4+input+devices+d4096.png" alt="" id="BLOGGER_PHOTO_ID_5463818963785840034" border="0" /></a><br />The red spectrum in the Average window shows a strong +15 dB tone at +586223 Hz. The Histogram window shows the noise to have a nice Gaussian shaped curve. The Gaussian window was used to improve the spectral time resolution. The Color Aperture window was set to a -27 ... -61 dB range to improve the color resolution of the spectrogram. The green spectrogram window shows what previously was a constant stationary tone is now a drifting signal that has a slight random walk. Note that the spectrogram's horizontal zoom has been changed to Hz=1X. Here is a full screenshot:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhug8Mv2C_AJIkPJejcqtO6ZYVb-eeIGXRXUqOlOBCaGzXs30iXW01EUpI76BD48Bkqjf5_F_y8HAfQf382ecMwldQZgVYvxz3zc2rgQ4egKS3nkkxX5kGihwqQc8NPd_bZ3icJ/s1600/kepler-exo4+d4096+a.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhug8Mv2C_AJIkPJejcqtO6ZYVb-eeIGXRXUqOlOBCaGzXs30iXW01EUpI76BD48Bkqjf5_F_y8HAfQf382ecMwldQZgVYvxz3zc2rgQ4egKS3nkkxX5kGihwqQc8NPd_bZ3icJ/s400/kepler-exo4+d4096+a.png" alt="" id="BLOGGER_PHOTO_ID_5463823778604251362" border="0" /></a><br />Making some measurements in the spectrogram window shows that the +586223 Hz signal has a drift of +4.30 Hz / 326 seconds = +0.0132 Hz / second. It starts as what looks like a random walk as the tone zigzags back and forth. Then something really interesting happens half way down, it looks like the signal is being modulated. Zooming in on the lower half and increasing the Gaussian beta value to 11 shows: (click on image for higher resolution version)<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh37Vt7n9Q0RpFQemb2_MCbsUcAO6F7I55k51FuEjHw9xtBBAgMqyu7jtspaAlVHhJPOlvlm4NoF922rqCKr7Qw4dwGcRgj0hk6rJrl4w5jX0wKZPzJ5Bj0Yeocl6opS_1pVZHg/s1600/kepler-exo4+d4096+b.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 356px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh37Vt7n9Q0RpFQemb2_MCbsUcAO6F7I55k51FuEjHw9xtBBAgMqyu7jtspaAlVHhJPOlvlm4NoF922rqCKr7Qw4dwGcRgj0hk6rJrl4w5jX0wKZPzJ5Bj0Yeocl6opS_1pVZHg/s400/kepler-exo4+d4096+b.png" alt="" id="BLOGGER_PHOTO_ID_5463828348245230386" border="0" /></a><br />This looks like <a href="http://baudline.com/manual/glossary.html#FSK">FSK</a> modulation with the delta between mark and space frequencies being about 1.2 Hz. Below is the Average spectrum showing the mark and space frequencies:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8vNAvQCNzlB0SCCTRQ49rgaFLOxrzorfnRuGaHr3RwLzDMdT_1zkAU4bSKJx8PAtmQxUMUXNolG5Nmho1v299m4UO68y2R418fAuhNNxQ859nQkPbf-khYYw-eEpyl1EtaqCa/s1600/kepler-exo4+average+FSK.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 215px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8vNAvQCNzlB0SCCTRQ49rgaFLOxrzorfnRuGaHr3RwLzDMdT_1zkAU4bSKJx8PAtmQxUMUXNolG5Nmho1v299m4UO68y2R418fAuhNNxQ859nQkPbf-khYYw-eEpyl1EtaqCa/s400/kepler-exo4+average+FSK.png" alt="" id="BLOGGER_PHOTO_ID_5463883020287198274" border="0" /></a><br />The purple spectrum is from the beginning of the modulated section. Since the signal is drifting with a positive slope the mark and space frequencies move to the right. The green spectrum is from the mid/bottom of the modulated section. This is clearly 2-tone FSK but at an extremely low baud rate with a very close mark and space frequency delta.<br /><br /><br /><span style="font-size:180%;">Enhance Resolution</span><br />The new <span style="font-weight: bold;">blip Fourier</span> transform enhances spectral resolution which is ideal for deep zooming down to the sample level. Time, frequency, and phase details are improved by using a new analysis primitive called the blip(let). A focus parameter allows for algorithm fine tuning on a signal by space by zoom basis.<br /><br />Zooming into the FSK signal using a second decimation pass for a total decimate by ratio of 524288 and a bin resolution of 0.01628 Hz / bin. With focus=1 the structure of the individual FSK bits are clearly visible in the magnitude space view below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxsx8RnLLl5ardSK0Iqrb6xBCw3G2GnwQC9cWsD8Qpq-PKkKEqa5kPKd9BnildRDOZJD_x-1ABgK_LQBO_F1AKd1PNblJUGMX2ADRpQbq1t5tICOaiMgUgWT4BDja3Dby1Gn75/s1600/kepler-exo4_FSK_mag_f1.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 376px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxsx8RnLLl5ardSK0Iqrb6xBCw3G2GnwQC9cWsD8Qpq-PKkKEqa5kPKd9BnildRDOZJD_x-1ABgK_LQBO_F1AKd1PNblJUGMX2ADRpQbq1t5tICOaiMgUgWT4BDja3Dby1Gn75/s400/kepler-exo4_FSK_mag_f1.png" alt="" id="BLOGGER_PHOTO_ID_5467955087034800594" border="0" /></a><br />Also part of the <span style="font-weight: bold;">blip Fourier</span> transform is a blind phase lock algorithm that tracks changes in phase. The problem of spinning phase that is inherent in the short-time Fourier transform (STFT) is solved with blind phase locking. Now the other half of the spectrum, the phase half, contains visibly useful information. With focus=4 the phase of the FSK bits are fairly constant in the unwrapped phase space view below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrPaJ0TfDXkRKR9E9JbMNuWvF9WpBE2kpMzw2hHzh-oA6xFWXkfdMawcYKJ0kaBPSJ1JsuRrH3sthndw-w72dHlpbwaVThJCQrIYoNT9A1J1l-nwD-NF9GhwAl_zWIrQeOJgZ8/s1600/kepler-exo4_FSK_phase_f4.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 376px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrPaJ0TfDXkRKR9E9JbMNuWvF9WpBE2kpMzw2hHzh-oA6xFWXkfdMawcYKJ0kaBPSJ1JsuRrH3sthndw-w72dHlpbwaVThJCQrIYoNT9A1J1l-nwD-NF9GhwAl_zWIrQeOJgZ8/s400/kepler-exo4_FSK_phase_f4.png" alt="" id="BLOGGER_PHOTO_ID_5467955105345563618" border="0" /></a><br />The visible phase changes follow what is expected for a random walk coupled with FSK mark/space transitions. There is a fair amount of phase noise present but it does not appear that any phase coding exists within the steady state or the bit transitions.<br /><br />In the spectrum section above the dB axis is incorrect. Since this is phase space the units should be {-pi ... +pi}. This will be fixed in a future version of baudline.<br /><br />Also note that the spectrogram timebase parameter for the above images was set to 3X. The overlap value was 1 so this means that baudline can zoom in three more scale factors before the digital bottom is reached at the discrete sample level.<br /><br /><br /><span style="font-size:180%;">Demodulation</span><br />Since the entire FSK signal is drifting somewhat randomly at about +0.0132 Hz/sec machine demodulation is a bit difficult. Backed decimation up a notch from the previous Enhanced Resolution section since the following demodulation works better with a little less zoom. Used a second decimation pass, like was done previously, for a total decimate by ratio of 262144 and a bin resolution of 0.03255 Hz / bin. Baudline's <a href="http://baudline.com/manual/display.html#periodic_bars">periodicity bars</a> were used to place and fine tune a horizontal grid that perfectly matched the modulated FSK symbols. See the two slightly overlapped spectrograms that have the periodicity bar overlays below: (click on image for higher resolution version)<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXgZYDKuHX0bJy6mvz2hqVb22Y2ijv_-hOJ9gyrshGwgb48iuM0p-K6xn49AGHfOzMtJ8SgjOmw4LAu3Ui_PLPq3bN4QDp821isWSqK-gqw1W2gOCTj0hbpgxr3j0VY62fSeYG/s1600/kepler-exo4+FSK+periodicity1.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXgZYDKuHX0bJy6mvz2hqVb22Y2ijv_-hOJ9gyrshGwgb48iuM0p-K6xn49AGHfOzMtJ8SgjOmw4LAu3Ui_PLPq3bN4QDp821isWSqK-gqw1W2gOCTj0hbpgxr3j0VY62fSeYG/s400/kepler-exo4+FSK+periodicity1.png" alt="" id="BLOGGER_PHOTO_ID_5464592811839839090" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCX1TGUBYwBE-OJ_Xff1HIfJy_nS7yfJesw_wxF6iwwQ3x-qo0pSj6Uae1pYECG1q8O4j-JDtMtfzCBiuL94tLKqh4nZRsrmo94BgKlRDkjmmrJG607YPUMOUtvtuS-JCR5UQo/s1600/kepler-exo4+FSK+periodicity2.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCX1TGUBYwBE-OJ_Xff1HIfJy_nS7yfJesw_wxF6iwwQ3x-qo0pSj6Uae1pYECG1q8O4j-JDtMtfzCBiuL94tLKqh4nZRsrmo94BgKlRDkjmmrJG607YPUMOUtvtuS-JCR5UQo/s400/kepler-exo4+FSK+periodicity2.png" alt="" id="BLOGGER_PHOTO_ID_5464593145585385730" border="0" /></a><br />Note that FSK2 modulation has one symbol per baud. From the periodicity bars delta selected value the baud rate was measured to have a period of 1.976 seconds which is 0.5061 baud. This works out to a spectral efficiency of roughly 0.17 (bit/s)/Hz.<sup>2</sup> The periodicity bars sliced the symbols perfectly. With the periodicity bars up I was able to manually demodulate the individual bits. Here are the demodulated bits, it begins with a large number of leading zeroes:<br /><span style="font-family:courier new;"><br /></span><span style="font-family:courier new;">00000000000000000000000000000000000000000000000<br />10100010001010101010010000000000101010101001010<br />10101010101010101010101010010101010101010101010<br /></span><br />In an attempt to make some sense of this bit stream here are the demodulated bits in a reduction grammar notation:<sup>3</sup><br /><span style="font-size:100%;"><span style="font-size:85%;"><span style="font-family:courier new;"><br />0* 2(10) 00 1(10) 00 5(10) 0 1(10) 9(0) 5(10) 0 15(10) 0 10(10)+<br /></span></span></span><br />where the 0's and 1's are bits and the bit string in parenthesis is repeated by the number before it. The pattern is mostly repeating 10's interspersed with an occasional 0 or two.<br /><br />Ignoring the leading zeroes, here is the bitstream broken down into 32-bit hexadecimal integers (big endian):<br /><span style="font-family:courier new;"><br />10100010 00101010 10100100 00000000 = 0xA22AA400<br />10101010 10010101 01010101 01010101 = 0xAA955555<br />01010101 00101010 10101010 101010.. = 0x552AAAA.<br /></span><br />There are 55 zero bits and 39 one bits which is somewhat lopsided but the sample size is way to small for that to be significant. It is interesting that there is not a single run of ones (11) in the bit stream which would suggest some form of Non-Return-to-Zero Inverted (NRZI) coding.<sup>4</sup><br /><br />The bit stream is definitely not random but I haven't been able to decode a pattern out of it yet. It is also possible that the demodulation process produced a couple of bit errors. It is also unfortunate that the data file terminated when it did. Plugging this bit stream (and parts of it) into Google returns zero hits. Maybe some bit wackers<sup>5</sup> or crypto folk can pull meaning out of this bit stream.<br /><br /><br /><span style="font-size:180%;">Listen</span><br />The decimated quadrature FSK signal was mixed up to passband (real). To hear this signal download the <a href="http://baudline.com/misc/kepler-exo4_FSK.wav">kepler-exo4_FSK.wav</a> file, load it into baudline, then open the <a href="http://baudline.com/manual/play_deck.html#play_deck">Play Deck</a> window to adjust the audio controls, and press play.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrPIIA1DWI44H_-nJHzoSXxExxr4FTdG2h1xzCK69XWCZiPxAfgwIHmfZ3TCULB6PLTNScT3RDJhw1dC4MFOXW3W4z4Q3XRFMvd4Tlg5P_L7sVgICAjBwjJbNpVhI1dLDo89ta/s1600/kepler-exo4_play_deck.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 386px; height: 271px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrPIIA1DWI44H_-nJHzoSXxExxr4FTdG2h1xzCK69XWCZiPxAfgwIHmfZ3TCULB6PLTNScT3RDJhw1dC4MFOXW3W4z4Q3XRFMvd4Tlg5P_L7sVgICAjBwjJbNpVhI1dLDo89ta/s400/kepler-exo4_play_deck.png" alt="" id="BLOGGER_PHOTO_ID_5470222028655779570" border="0" /></a><br />You can slow down the sample rate by adjusting the speed control or change the center down mix frequency by adjusting the shift control. Pressing the small arrow in the bottom right corner will pop down a section that has more controls. From there you can apply an equalization curve or adjust low and high pass filters to remove out-of-band noise.<br /><br /><br /><span style="font-size:180%;">Autocorrelation</span><br />The random walk wandering FSK signal was then ran through baudline's Autocorrelation transform. The Autocorrelation transform shows the self similarity of a signal and it can also be utilized as a form of waveform trigger lock mechanism. Think of Autocorrelation as a sort of self syncing waveform raster display.<br /><br />For reference the Color Aperture window parameters were set to upper=-48 dB and lower=-69 dB. All other parameters except the windowing function are default. The <a href="http://baudline.com/manual/equalization.html#windowing">Kaiser window</a> was used and the beta parameter was increased from 0. to 15. in steps to create the following Autocorrelation spectrogram images:<br /><br />beta = 0. (square window)<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_Kut8qtc7qnEhk9hQqw3ZEXGGQuoUOziHSWNnh6EqT_IP4YtMs-t-1wz-rjTlUXC_hcOYlYZiJpUCWLoD9G60wKDbu9lz6X_BwApI0Q1StzgSKJ43kHUi6nWv8yz_3mjyoubq/s1600/kepler-exo4_FSK_autocorrelation_k0.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 372px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_Kut8qtc7qnEhk9hQqw3ZEXGGQuoUOziHSWNnh6EqT_IP4YtMs-t-1wz-rjTlUXC_hcOYlYZiJpUCWLoD9G60wKDbu9lz6X_BwApI0Q1StzgSKJ43kHUi6nWv8yz_3mjyoubq/s400/kepler-exo4_FSK_autocorrelation_k0.png" alt="" id="BLOGGER_PHOTO_ID_5468259030427410834" border="0" /></a><br />beta = 5.<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB0v4R77k6Wvk1hpCg4Ri2VKcDjoooUWBI-CUwRThnYVP-7-t1MMGmjQz0sf9zXYMtvcU4H8iubqOI7nUEX0jcLXzYHrd-Wbedcv2r-nF4PgCwvQZZu_lfoV3gR___B42KW9Vr/s1600/kepler-exo4_FSK_autocorrelation_k5.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 372px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiB0v4R77k6Wvk1hpCg4Ri2VKcDjoooUWBI-CUwRThnYVP-7-t1MMGmjQz0sf9zXYMtvcU4H8iubqOI7nUEX0jcLXzYHrd-Wbedcv2r-nF4PgCwvQZZu_lfoV3gR___B42KW9Vr/s400/kepler-exo4_FSK_autocorrelation_k5.png" alt="" id="BLOGGER_PHOTO_ID_5468259044034840002" border="0" /></a><br />beta = 15.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsOOLZSiEuaP3MtlO1CnlOscfW35nmsIYqVkf6gVnIKyJ67WXQ1LItXFEcKKM_fu3rYjFiF_WuWGkChCtbZ4tWGrPapelmaidz8CEDLEKKzxMqcVBPO3_N2iAS8iOK9XArqJEJ/s1600/kepler-exo4_FSK_autocorrelation_k15.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 372px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsOOLZSiEuaP3MtlO1CnlOscfW35nmsIYqVkf6gVnIKyJ67WXQ1LItXFEcKKM_fu3rYjFiF_WuWGkChCtbZ4tWGrPapelmaidz8CEDLEKKzxMqcVBPO3_N2iAS8iOK9XArqJEJ/s400/kepler-exo4_FSK_autocorrelation_k15.png" alt="" id="BLOGGER_PHOTO_ID_5468259712292206802" border="0" /></a><br />The progression of the Kaiser beta value shows how the structure evolves as the window gets narrower. No beta value here is inherently correct but the structures seem to stabilize with the higher betas.<br /><br />Here is an Autocorrelation movie of the variation of the Kaiser window beta. Notice how patterns and structures pop out of the noise as the beta parameter changes. The audio in the movie is the sound of the drifting random walking FSK signal that has been speed and frequency shift modified for the audio band. Make sure to watch this in fullscreen 720p HD so you can see all the details.<br /><br /><object height="340" width="480"><param name="movie" value="http://www.youtube.com/v/DJIFDRjPySc&hl=en_US&fs=1&rel=0&color1=0x234900&color2=0x4e9e00&hd=1"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/DJIFDRjPySc&hl=en_US&fs=1&rel=0&color1=0x234900&color2=0x4e9e00&hd=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="340" width="480"></embed></object><br /><br />This is not random noise and this is not what the Autocorrelation of a random walk looks like. I was expecting to see the FSK bits flipping on and off from a synchronized waveform perspective. That didn't happen and what this is is a lot more than 94 bits worth of structure. Also the drifting random walk isn't random at all, it contains information. What I believe is happening is that the drifting random walk and the FSK bit stream are modulated together to create this image. I've never heard of a modulation scheme like this before. It does have elements of NTSC and Hellschreiber to it but at an extremely low data rate.<br /><br />I tried different FFT sizes and different time domain operations from the <a href="http://baudline.com/manual/channel_mapping.html#channel_mapping">Input Mapping</a> window that cause various signal distortions. The basic image structure did not change. This tells me that the signal is fairly robust and not an artifact created by the analysis equipment.<br /><br /><br /><span style="font-size:180%;">Conclusion</span><br />The importance of this analysis depends greatly on the identity of the target source. Is it the Kepler satellite, the Kepler-4 planet, or something else? It is very unlikely an error in the collection or analysis caused the modulated bit section because other features in this data file are stationary or drifting differently. It is extremely unlikely that the modulated bits were created by natural phenomena. Decoding of the bit stream may prove enlightening in identifying the source. The Autocorrelation images are likely an interesting byproduct of the FSK data stream coupled with the drifting random walk.<br /><br />I really don't know what to say or think at this point. The SETI Institute collected this signal and they, hopefully, will tell us what the celestial source is. [Update: This <a href="http://setiquest.org/forum/topic/baudline-analysis-kepler-exoplanet-4">thread</a> confirmed the signal source to be the <a href="http://kepler.nasa.gov/Mission/discoveries/kepler4b/">Kepler 4b star</a>.]<br /><br />Some important questions about the FSK modulated signal:<br /><ul><li>Is the signal's proximity of -500 kHz to hydrogen significant or is it an aliasing artifact?</li><li>Are the other tones related in any way? (harmonically or temporally)<br /></li><li>Why is the signal drifting at a +0.0132 Hz/second rate? What should it be drifting at?</li><li>Why is it undergoing a random walk?</li><li>Why are the mark and space frequencies so close together? (1.2 Hz)</li><li>Why is the 0.5061 baud rate so low?</li><li>Do these modulation parameters match any known modem or system?<br /></li><li>Do the demodulated bits match any known line coding, preamble, or training sequence?</li><li>Why is there not a single run of ones (11) in the bit stream?<br /></li><li>Are there any "interesting" sequences or patterns in the demodulated bits?</li><li>Is there any significance to the Autocorrelation images?<br /></li><li>Will this signal ever be seen or collected again?<br /></li></ul>Does anyone have any answers or ideas?<br /><br /><div>[Update: The SETI Institute did a re-observation of the Kepler-4 target and the analysis report is here <a href="http://baudline.blogspot.com/2010/09/setiquest-kepler-4b-redux.html">setiQuest Kepler-4b redux</a>.]<div><br /><span style="font-size:85%;">Footnotes<br />1. Decimating by 4096 has the effect of increasing SNR but with the byproduct of reducing gain. Since baudline uses a 16-bit internal sample size this gain reduction can push any weak signal past the LSB thus truncating it. The +30 dB decimation gain setting improves the quantization SNR which eliminates the potential signal loss problem. Note that SNR has been used twice here in this note but in different contexts.<br />2. This spectral efficiency is roughly equal to that of a 110 baud Bell 101 FSK modem.<br />3. A context-free grammar is a Computer Science tool that is used to define a formal language. They are very useful in the design of finite automata. Their reduction ability can simplify a complex repetitive string down to it's basic structure.<br />4. Non-return-to-zero (NRZ) is a telecommunication line coding technique that is useful for overcoming channel deficiencies and for dealing with clocking or synchronization issues.<br />5. Yes, "bit wacker" is a technical term.<br /></span></div></div>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com4tag:blogger.com,1999:blog-19780926.post-19409003504747047762010-04-22T11:38:00.000-07:002010-09-26T17:23:01.391-07:00setiQuest amc7-3693.4464 MHzUsing the <a href="http://baudline.com/">baudline signal analyzer</a> to browse the <a href="http://setiquest.org/">setiQuest</a> 2010-04-02-amc7-3693.4464 data file. It took most of a day to download the 3 parts of the amc7 data files (5.7 GB) and combine them. This radio telescope data file is way too big to load so it had to be streamed into baudline. Two benefits of streaming to standard input are that you can see the recorded signal data scroll by and that the Input Device's "decimate by" feature can be used to further increase the signal extraction power.<br /><br />The following command line was used to stream the 5m 26s <a href="http://baudline.com/manual/options.html#quadrature">quadrature</a> setiQuest signal into baudline:<br /><br /><span style="font-size:85%;"><span style="font-family:courier new;">cat ~/setiquest/2010-04-02-amc7-3693.4464-8bit_combined.dat | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -flipcomplex -samplerate 8738133 -fftsize 65536 -utc 0 -pause</span></span><div><br /><span style="font-size:180%;">Full 8.738 MHz view</span><br />Switching baudline to the record mode allowed the standard input to be collected and displayed. The red Average window reduces the variance of the noise floor and lets weak signals stand out. The green spectrogram is a time vs. frequency plot which shows the presence of several constant tones (straight lines). The Histogram window shows a Gaussian curve (see <a href="http://baudline.com/manual/glossary.html#AWGN">AWGN</a>) which is customary for noise sampled from an analog digital converter (ADC), notice the alternating blank vertical lines caused by the signed 8-bit sample format. The Color Aperture window allows the upper and lower spectrogram intensity limits to be adjusted for maximum visual <span style="font-size:0;">sensitivity. </span>See the screenshot below (click for a larger image):<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdI9cF5kOyhFhaoe4DOETvQtd18XrsV1LfG324oYYeJYKzUWWrpBOLJ9XTf74XoAMhgvggMPrPJFiVfgbCIUdmK0-9JH_LZ-pKTaiIKf6BxlD_JVIeBCpBenhaCpDgpu-5cF4G/s1600/amc7-3693.4464.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdI9cF5kOyhFhaoe4DOETvQtd18XrsV1LfG324oYYeJYKzUWWrpBOLJ9XTf74XoAMhgvggMPrPJFiVfgbCIUdmK0-9JH_LZ-pKTaiIKf6BxlD_JVIeBCpBenhaCpDgpu-5cF4G/s400/amc7-3693.4464.png" alt="" id="BLOGGER_PHOTO_ID_5463055837259377762" border="0" /></a><br />A 65536 point complex <a href="http://baudline.com/manual/glossary.html#FFT">FFT</a> was used for display and analysis. The frequency axis was zoomed in to a Hz=1X resolution to focus on the tones at +500 kHz. The screenshot of the zoomed in Average window is below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigX4U5GVZtyX-dVWVmaFBA39YN19zfjytsOGwZ5usCVl9typJx8slPKp4KCOoYfh8Uo0RJvjtUQU8MjpVtLb744fWRDq8xs5YFAcMcIyNueNzbCc_ScVzaVfosW4kkmcQY3Qig/s1600/amc7-3693.4464+average.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 116px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigX4U5GVZtyX-dVWVmaFBA39YN19zfjytsOGwZ5usCVl9typJx8slPKp4KCOoYfh8Uo0RJvjtUQU8MjpVtLb744fWRDq8xs5YFAcMcIyNueNzbCc_ScVzaVfosW4kkmcQY3Qig/s400/amc7-3693.4464+average.png" alt="" id="BLOGGER_PHOTO_ID_5463057364440818050" border="0" /></a><br />The main tone is at 473 kHz with several weaker distortion sidebands. Next we want to zoom in even more to see what is going on.<br /><br /><br /><span style="font-size:180%;">Decimate by 512</span><br />The decimation and down mixer feature in the <a href="http://baudline.com/manual/input.html#input_devices">Input Devices</a> window was used to zoom into the frequency axis which also has the side benefit of increasing the signal's SNR. Decimation by 512 was done combined with a 65536 point FFT which has the equivalent extraction power of a 32 million point FFT. This works out to a bin resolution of 0.52 Hz / bin. The down mixer is a digital down converter (<a href="http://baudline.com/manual/glossary.html#DDC">DDC</a>) which works a lot like turning a radio tuner. The down mixer was set to be centered on the strong tone at +473 kHz by setting the frequency range to +464533.3 ... +481600.0 Hz.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVlf5jszMi73TRhvdw3koTZWJR5vh-qzuOb3DvTQUIEloSUJ2JOQGFDoBusqGfothDQ19UpjzsUALnzZ31S0_aLj0hBhA7RGYNN-bR2uxs4ZObvsFdYQ8M7EhQGP6psnz2rjMl/s1600/input+devices+stdin+DDC.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 390px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVlf5jszMi73TRhvdw3koTZWJR5vh-qzuOb3DvTQUIEloSUJ2JOQGFDoBusqGfothDQ19UpjzsUALnzZ31S0_aLj0hBhA7RGYNN-bR2uxs4ZObvsFdYQ8M7EhQGP6psnz2rjMl/s400/input+devices+stdin+DDC.png" alt="" id="BLOGGER_PHOTO_ID_5463082774962335522" border="0" /></a>Interesting side note is the 8.3 Msample calibration rate estimate for stdin. The sample rate estimate is a clock measurement of the speed baudline is collecting data, in this case from stdin. This means that baudline is collecting standard input data from a file, decimating, down mixing, calculating a 65536 point FFT, accumulating the Average window, calculating and drawing the sample Histogram, and rendering the scrolling spectrogram in almost real-time on a cheap $500 one-year-old 2.0 GHz Intel Core 2 Duo machine.<br /><br />Next, the "transform cache" feature was enabled in the Drift Integrator which used 524 MB of RAM to cache the results of the 65536 point FFT for extremely fast frequency axis zooming and scrolling. The Drift Integrator has a number of other useful features such as beam slices, Auto Drift, a folding paste algorithm, and anti-alias on spectrogram zoom which I will explain in a future blog post.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtM3UrTztuUG9VFtPHsnP9Hbtz1OZUp7VF-tPHj6tXYMj7g0W2CaAIRY8ry-ZvGCQSChCtW57bh5U8WPFVHlvJVrasu54Me01R928RpkODKXFp7HdfSue1Y8_tgW95m0-5IByO/s1600/drift+integrator.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 267px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtM3UrTztuUG9VFtPHsnP9Hbtz1OZUp7VF-tPHj6tXYMj7g0W2CaAIRY8ry-ZvGCQSChCtW57bh5U8WPFVHlvJVrasu54Me01R928RpkODKXFp7HdfSue1Y8_tgW95m0-5IByO/s400/drift+integrator.png" alt="" id="BLOGGER_PHOTO_ID_5463084086069155650" border="0" /></a><br />Below is a full screenshot of the result of the decimation and down mixing:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLz2Bb0-Bf-guRNsrj5tipavIEeK9Xb281iakTx5DC6kA4HVU6UR1awwyJj6YCcy1SkTD84Jx3oYnWQmbyKQy3JXNoIZpRYa519Y0a71bt7lUtZ4RBo1RetrVFRJ804-RYqiu1/s1600/amc7-3693.4464+:512+%2B464533+Hz%3D32X.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLz2Bb0-Bf-guRNsrj5tipavIEeK9Xb281iakTx5DC6kA4HVU6UR1awwyJj6YCcy1SkTD84Jx3oYnWQmbyKQy3JXNoIZpRYa519Y0a71bt7lUtZ4RBo1RetrVFRJ804-RYqiu1/s400/amc7-3693.4464+:512+%2B464533+Hz%3D32X.png" alt="" id="BLOGGER_PHOTO_ID_5463037770963409986" border="0" /></a><br />The red Average spectral plot and the green spectrogram show the same range of frequency data but at different Hz scale factors. The strong tone at 473067 Hz and its sidebands are the main concern of interest here. Notice the first sidebands offset by ±979 Hz on both sides of this strong 473 kHz tone are wiggly. Next we will zoom in on one of them.<br /><br /><br /><span style="font-size:180%;">Zoom Hz=1X</span><br />The Command+Left key was pressed several times to change the spectrogram's frequency zoom factor from 32X to 1X. Since the "transform cache" was enabled the zooming and frequency scrolling was extremely fast and responsive. It was like exploring the spectrum with a real-time <a href="http://baudline.com/manual/glossary.html#DSP">DSP</a> microscope looking for interesting spectral features. A screenshot of the wandering tone (F2) at 472075 Hz is below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyldjt5G5JwzjiFWxeT5mwAqOdsZ1IHXu4xgUl-3l1PCwRBP8tWU1jINuOa7EroMkDrovWgk9ZpWHL-iQK_ON1LeQr6Pq-LvhTNbzbsIXquP_JMsvSgTKgOnGUenLhzRM2n3fX/s1600/amc7+-f2.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 267px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyldjt5G5JwzjiFWxeT5mwAqOdsZ1IHXu4xgUl-3l1PCwRBP8tWU1jINuOa7EroMkDrovWgk9ZpWHL-iQK_ON1LeQr6Pq-LvhTNbzbsIXquP_JMsvSgTKgOnGUenLhzRM2n3fX/s400/amc7+-f2.png" alt="" id="BLOGGER_PHOTO_ID_5463395943919828578" border="0" /></a><br />It was interesting to discover that the sidebands, offset by ±979 Hz, are mirror images of each other. The sidebands (F2) are about 25 dB down from the main tone (F1). The third ±harmonics (F3) are also wandering mirror images of F2, the F4 harmonic is missing, while the F5 is a clean constant tone. Here is a screenshot of -F3:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQM28JUSp8Xf3WAoUi6xwNV2_X1INxfEDWry_p1l6SfyQYZdqtedPxlu11xdso1-uJrbwmsH2HnpS5ydg_yAPVuwgJl96tBcCvTni1Bstr6CMJXUpeuPlwBcglK8J1tEYaehj6/s1600/amc7+-f3.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 267px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQM28JUSp8Xf3WAoUi6xwNV2_X1INxfEDWry_p1l6SfyQYZdqtedPxlu11xdso1-uJrbwmsH2HnpS5ydg_yAPVuwgJl96tBcCvTni1Bstr6CMJXUpeuPlwBcglK8J1tEYaehj6/s400/amc7+-f3.png" alt="" id="BLOGGER_PHOTO_ID_5463396027892697298" border="0" /></a><br />The wandering -F3 tone is just a weaker version of -F2 with 2x the frequency stretch which is customary for harmonic progressions.<br /><br />Amplitude modulation (AM) of the strong 473 kHz tone by an unknown signal would cause similar sidebands. They could be distortion products from the transmitter or the radio telescope collection equipment. The wandering looks like it could be oscillator drift of the ADC sampling clock but that is just a guess.<br /><br />Let's move the frequency scrollbar to look at the strong 473069 Hz tone. Here is a screenshot of the carrier (F1):<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnvtvGwJqx_2njjFD5eW7dlKYWGPbbsE23KSCKmgpEUp5DmIqTEI6b6jn_OM7QPqsMhZhx8tTZn7mLjbmdWZcjyZLyolHuytEvhhmG6X6bCu_Bb7ZlO1j5iZdMvCyIUTp84AUQ/s1600/amc7+f1.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 267px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnvtvGwJqx_2njjFD5eW7dlKYWGPbbsE23KSCKmgpEUp5DmIqTEI6b6jn_OM7QPqsMhZhx8tTZn7mLjbmdWZcjyZLyolHuytEvhhmG6X6bCu_Bb7ZlO1j5iZdMvCyIUTp84AUQ/s400/amc7+f1.png" alt="" id="BLOGGER_PHOTO_ID_5463396131055538834" border="0" /></a>It looks very stationary and popping up baudline's crosshair cursor verifies such at this magnification level.<br /><br /><br /><span style="font-size:180%;">Decimate by 4096</span><br />Let's zoom in a little more. Increasing the decimation factor to 4096 reduces the bin resolution to 0.0651 Hz / bin. Below is a spectrogram screenshot of the strong carrier (F1) at this increased frequency resolution:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKNQShHPAikGavc_6wRDqBOJPeTa5Og8MdforesmpykfWkm7THvJQ4NIo0oG8HVQKXBIqllI65y73uwYosXOppUT58g-PSJ5wycMhm_GJGw3LxjGK8QYeIHkiBKIgvwxXVHzWq/s1600/amc7+d4096.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 267px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKNQShHPAikGavc_6wRDqBOJPeTa5Og8MdforesmpykfWkm7THvJQ4NIo0oG8HVQKXBIqllI65y73uwYosXOppUT58g-PSJ5wycMhm_GJGw3LxjGK8QYeIHkiBKIgvwxXVHzWq/s400/amc7+d4096.png" alt="" id="BLOGGER_PHOTO_ID_5463114531594256498" border="0" /></a>The strong tone has a slight drift of +0.52 Hz over a course of 326 seconds. This is about equal to the bin resolution from the previous decimate by 512 case so it isn't surprising that the signal looked stationary in that view. The increased frequency zoom has made the signal start to look a bit wiggly. What we need is even more frequency resolution.<br /><br /><br /><span style="font-size:180%;">Decimate by 32768</span><br />Baudline has a maximum "decimate by" limit of 4096 so I used a 2-pass method of decimating by 4096, saving the file, then feeding that into standard input again but with a decimate by 8 factor. I call this multi-pass algorithm "decimate by ∞" where you keep taking the output of the decimator and feed it back into the input. You can keep doing this ad infinitum until you end up with zero samples. I could of kept decimating past 32768 but too much time information would of been lost from the spectrogram and resulted in a poor looking image. The bin resolution of decimate by 32768 is 0.00814 Hz / bin. The once stationary tone no longer looks straight in the spectrogram below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMsfFhfp5mRLbPW2NxoSKWtznSVuP408ChdpT__yIa0_0vDhvpomxa0OmUgRmVklBbJ4VzuScDn8AJ89wgegabLS0271WURzfOiHcDKCkTQLy7-Eaid-AeEJfqEA1FYNJ420hy/s1600/amc7+d32768.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 267px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMsfFhfp5mRLbPW2NxoSKWtznSVuP408ChdpT__yIa0_0vDhvpomxa0OmUgRmVklBbJ4VzuScDn8AJ89wgegabLS0271WURzfOiHcDKCkTQLy7-Eaid-AeEJfqEA1FYNJ420hy/s400/amc7+d32768.png" alt="" id="BLOGGER_PHOTO_ID_5463121589119093026" border="0" /> </a><br />The tone isn't just drifting, it also has an incredible amount of wander to it. I measure a top to bottom drift of +0.35 Hz over 326 seconds. This isn't surprising, zoom in deep enough and even the world's best oscillator is will have some variation but more likely you'll be seeing the error in the ADC clock!<br /><br />I've seen this deep decimation frequency wandering before in this <a href="http://baudline.com/mystery_signal/11.html">Mystery Signal</a>.<br /><br />For fun this is what the decimate by 32768 quadrature signal looks like in the Waveform view:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCO4RnBvGQcT-NEGgnL9Je2GEqZJYOvqPYYWSKO0FMGg7LJeadxRJkyIqZuvPGEcQGK_QO2CRqz4acbudYh-X-yNiTZg8Oe4HyMm6CI_YkzzqJAtTXXi4hcFVLEm5CZWOFhyphenhyphenRc/s1600/waveform+d32768.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 114px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCO4RnBvGQcT-NEGgnL9Je2GEqZJYOvqPYYWSKO0FMGg7LJeadxRJkyIqZuvPGEcQGK_QO2CRqz4acbudYh-X-yNiTZg8Oe4HyMm6CI_YkzzqJAtTXXi4hcFVLEm5CZWOFhyphenhyphenRc/s400/waveform+d32768.png" alt="" id="BLOGGER_PHOTO_ID_5463121756236807698" border="0" /></a>Note that most of the noise has been decimated away and a quadrature sine wave is visible. Nice 90º phase shift.<br /><br /><br /><span style="font-size:180%;">Conclusion</span><br />The combination of a large FFT and high decimation factor allow baudline to zoom in for a deep view of weak signal behavior. Using baudline's multiple features allowed for detailed signal measurements and interactive fast browsing of the time-frequency domain.<br /><br />The setiQuest AMC-07 data file had several stationary tones with strong distortion sidebands. The wandering mirror sidebands are likely caused by oscillator drift of the ADC sampling clock. The non-drifting stationary nature of all tones in this data file suggest the source is of terrestrial origin.<br /><br />[Update: This <a href="http://setiquest.org/forum/topic/baudline-analysis-amc-07">thread</a> said that the signal is from the AMC-7 geosynchronous satellite.]</div>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1tag:blogger.com,1999:blog-19780926.post-15506588522821274852010-04-20T13:22:00.000-07:002010-09-18T14:30:43.665-07:00I joined setiQuestI joined the <a href="http://setiquest.org/">setiQuest</a> project that is being sponsored by the <a href="http://seti.org/">SETI Institute</a>. As their blog states, today truly is an exciting day. The setiQuest project is placing data sets collected from the Allen Telescope Array into the public domain. Their goal is to encourage "citizen scientists" to help in the search for extraterrestrial intelligence by analyzing radio telescope data and look for signals. Here is a <a href="http://baudline.com/">baudline</a> screenshot of the one second test .dat file:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfJTIRg9n-RS4OQNATEgjx3BJjFSoJbm4VFPWbdAL_XikPdQxpvFO6szilIk6dkz-87imo792do93TjVNWd1lPUi9nR4aW4CfI7YaCfPLnPNJXUa0hcYVcGf-BgYAeLD2hlMqO/s1600/amc7-3693.4464-8bit-one-second.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfJTIRg9n-RS4OQNATEgjx3BJjFSoJbm4VFPWbdAL_XikPdQxpvFO6szilIk6dkz-87imo792do93TjVNWd1lPUi9nR4aW4CfI7YaCfPLnPNJXUa0hcYVcGf-BgYAeLD2hlMqO/s400/amc7-3693.4464-8bit-one-second.png" alt="" id="BLOGGER_PHOTO_ID_5462319633097113778" border="0" /></a><br />The red spectral plot of the Average window shows a strong tone at -469 kHz and two weaker tones at around -2 MHz. The slopes on the left and right of the red Average spectral curve are from filters in the sampling unit or from a digital down conversion (DDC) process. The slight negative slope (-0.5 dB over 6 MHz) of the spectral curve is interesting, I'd expect it to be symmetrical around 0 Hz but it could be because this chuck of spectrum was extracted from a wider section of bandwidth.<br /><br />The green spectrogram plot shows that these tones are stationary for the one second file duration which is not long enough to determine if they are stationary or are drifting. I need to look at the larger 1.9 GB data file, that is still downloading, to know for sure. Looks like there might be some modulation but that could just be the noise. The tones are fairly weak signals and further analysis is required.<br /><br />The histogram on the right shows that sample data has a Gaussian distribution which is to be expected from radio telescope data. The histogram is centered at zero and it doesn't have any skew which is good.<br /><br />This one second test data file was streamed into baudline's standard input. The data format is 2-channel quadrature signed 8-bit samples. The sample rate was calculated by dividing the one second file size by 2 to be 8738133 samples/seconds. Here is the command line used:<br /><br /><span class="Apple-style-span" ><span class="Apple-style-span" style="font-size: small;">cat 2010-04-02-amc7-3693.4464-8bit-one-second.dat | baudline -session setiquest -stdin -format s8 -channels 2 -quadrature -samplerate 8738133 -pause<br /></span></span><br />So join setiQuest, download baudline, and start analyzing signals today.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1tag:blogger.com,1999:blog-19780926.post-80182680789999736842008-06-18T13:23:00.000-07:002010-11-12T15:58:06.801-08:00Ferranti Mark 1 computer musicThe BBC is reporting that it has unveiled the <a href="http://news.bbc.co.uk/2/hi/technology/7458479.stm">oldest known recording of computer generated music</a>. This recording was generated by the Ferranti Mark 1 computer at the University of Manchester in the Autumn of 1951. The Ferranti Mark 1 was the first computer to have a memory device that allowed it to run software programs. Previous computers of the day ran hardwired programs which were much more difficult to program.<br /><br />The <a href="http://www.baudline.com/spectrogram.html">baudline spectrogram visualizer</a> created the image below of the historic Ferranti Mark 1 computer music:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4uJA2MbPheNnX_aIACSVlRvqdrOAvZY51_ml48jJsWsqqB12XAJST6JObggZ0jRlaGihPVRfKXn9kbN03DTxeIcxQZudyfWVMU3_yVcM0IEISzW1tqhrotkrcqcK26GsZ0Sr/s1600-h/Ferranti_Mark_1_music.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4uJA2MbPheNnX_aIACSVlRvqdrOAvZY51_ml48jJsWsqqB12XAJST6JObggZ0jRlaGihPVRfKXn9kbN03DTxeIcxQZudyfWVMU3_yVcM0IEISzW1tqhrotkrcqcK26GsZ0Sr/s400/Ferranti_Mark_1_music.png" alt="" id="BLOGGER_PHOTO_ID_5213326411423450210" border="0" /></a><br />There are two interesting spectral features visible in the spectrogram.<br /><br />The first feature is the frequency folding at 1012 and at 2024 Hz. These mirror spectral images can be artifacts of a sample rate conversion with poor anti-alias filtering or they could be caused by modulation (<a href="http://www.baudline.com/manual/glossary.html#AM">AM</a> or <a href="http://www.baudline.com/manual/glossary.html#FM">FM</a>) of the audio output. Modulation is the likely explanation because the audio output is suspected to be a simple wire connection to one of the Ferranti's register bits. Toggling a register bit at a CPU clock frequency at about 1012 Hz could create similar modulation sidebands. The Ferranti Mark 1 had a standard instruction time of 1.2 ms and a multiplication instruction time of 2.16 ms which is near a 1 kHz clock rate. On a related note, <a href="http://www.baudline.com/mystery_signal/4.html">mystery signal #4</a> has similar modulation side-banding and the <a href="http://baudline.blogspot.com/2006/03/khoomei-acoustic-analysis.html">Khoomei Acoustic Analysis</a> blog post has similar frequency folding.<br /><br />The second spectral feature of interest was discovered with baudline's <a href="http://www.baudline.com/manual/display.html#harmonic_bars">harmonic measurement bars</a>. The harmonics of the musical notes are all missing their fundamental frequency. The exact cause is not known but a phantom fundamental is not easy to generate by bit twiddling. An analog filter or the frequency response of the loudspeaker could have caused this fundamental removal. Diode rectification is not the cause because the <a href="http://www.baudline.com/manual/channel_mapping.html#operation">|x| absolute value operation</a> moves the fundamental and it also moves the harmonics. On a related note the musical output is monophonic and has an apparent one octave range.<br /><br />For technical information about the Ferranti Mark 1 computer see:<br /><ul><li><a href="http://www.computer50.org/mark1/FM1.html">http://www.computer50.org/mark1/FM1.html</a></li></ul>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-25712330065750802252008-03-14T15:05:00.000-07:002013-05-07T17:10:03.851-07:00Cassini - Eerie Saturn Radio EmissionsThe <a href="http://www.baudline.com/spectrogram.html">baudline scientific visualizer</a> was used to investigate some <a href="http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1613">eerie Saturn radio emissions</a> captured by the Cassini spacecraft. NASA believes that the source of these radio waves are related to the auroras near the poles of Saturn. The 27 minute radio emission signal was collected by Cassini's radio and plasma wave instrument and has been compressed down to a 73.5 second audio file for playback.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfb6WSU91dSdeye7_yJhlqwKcLFUqGOjSrJbmx5gJpLwBN7Xz3EWUXefX-xW5Vz9thIX7314RM3SHwM6Dw0rK_2Xli2kb4k0VU1KAGIUE9ypbP6jk79s8Vyo1NHRB9ID4OT2ec/s1600-h/eerie_sounds_of_saturns_radio_emissions.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfb6WSU91dSdeye7_yJhlqwKcLFUqGOjSrJbmx5gJpLwBN7Xz3EWUXefX-xW5Vz9thIX7314RM3SHwM6Dw0rK_2Xli2kb4k0VU1KAGIUE9ypbP6jk79s8Vyo1NHRB9ID4OT2ec/s400/eerie_sounds_of_saturns_radio_emissions.png" id="BLOGGER_PHOTO_ID_5177737256426656466" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
This signal looks and sounds a lot like Earth VLF chorus with fading blobs of spectrum moving up and down in frequency. The large blocks visible throughout the spectrogram are interesting looking artifacts that could be synthesis or compression related. Another interesting artifact are the horizontal scan lines that can be seen in the zoomed in spectrogram image below:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBXW3e7iyNPg0zHPC-mTP3aPpEBuCdCe4KCCisgJjbOKJcF8p4KF_cv0Vo3hSF4L9fPZ2TpiCiNRUZOaJTYOnk2u3w54QJ42rnOh8Gglix_afHF-S55gEFkaUCBTJou8K9Lcy7/s1600-h/eerie_zoom_scan_lines.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBXW3e7iyNPg0zHPC-mTP3aPpEBuCdCe4KCCisgJjbOKJcF8p4KF_cv0Vo3hSF4L9fPZ2TpiCiNRUZOaJTYOnk2u3w54QJ42rnOh8Gglix_afHF-S55gEFkaUCBTJou8K9Lcy7/s400/eerie_zoom_scan_lines.png" id="BLOGGER_PHOTO_ID_5177751558667752162" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
The NTSC-like horizontal scan line artifacts could be synthesis based or they could be related to how the Cassini sensors operate. Baudline's <a href="http://www.baudline.com/manual/display.html#periodic_bars">periodicity bars</a> measured the scan lines to have a repetitive spacing of 0.1487 seconds which when multiplied by the 5000 sample becomes 743.5 samples. Adjusting for a 73.5 second to 27 minute file expansion, a reciprocal factor of 22.04, the number of samples becomes 16386.7 samples which is very close to 16384 a power of 2 and a popular buffer size.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1tag:blogger.com,1999:blog-19780926.post-75672321536620133292007-11-30T14:53:00.000-08:002008-12-11T21:51:05.966-08:00Fedora 8 vs. openSUSE 10.3 vs. Ubuntu 7.10Linux live-CD's are a great nondestructive way of auditioning Linux. Simply pop a live-CD into your CD drive, reboot, and then in a couple minutes you are running Linux. No hard drive partitioning, no lengthy installation process, no fuss. Linux live-CD's are also a quick and easy way to try many different Linux distributions. The latest Fedora, openSUSE, and Ubuntu live-CDs were tested for compatibility with the <a href="http://www.baudline.com/">baudline signal analyzer</a>.<br /><br />The following Gnome based Linux distributions were all released during October and November 2007 with live-CD versions:<br /><ul><li><a href="http://fedora.redhat.com/">Fedora 8</a></li><li><a href="http://www.opensuse.org/">openSUSE 10.3</a></li><li><a href="http://www.ubuntu.com/">Ubuntu 7.10</a></li></ul>Since they were released around the same time, all three use very similar versions of the Linux kernel, X-Windows, Gnome 2.20, and other common libraries. So it seemed like a great opportunity to compare them and see how well they worked with baudline. In theory the 3 different distributions all should of behaved in about the same way but they didn't. Another fine point is that all three Linux live-CD's advertised Xgl compiz 3D window effects but unfortunately none of the distributions supported this on our two test systems with the default video card drivers. For a review of a 3D compiz desktop see this <a href="http://baudline.blogspot.com/2006/03/kororaa-linux-xgl-livecd.html">Kororaa Linux Xgl LiveCD</a> review.<br /><br /><span style="font-size:180%;">Test Systems</span><br />We used two different 4-year old machines for the tests just to make sure that some unusual behavior wasn't being caused by an odd poorly supported piece of hardware. Here are the machine specs:<br /><ul><li>Intel Pentium IV 2.0 GHz</li><li>VIA P4X266 chipset</li><li>512 MB RAM DDR266</li><li>GeForce4 MX 440 AGP 4X video card</li><li>Creative Labs Sound Blaster 16 PCI ES1371</li><li>integrated VIA VT8235 audio chipset</li></ul>and<br /><ul><li>AMD Athlon XP 2600+ 2.1 GHz</li><li>nVidia nForce2 chipset</li><li>1.5 GB RAM DDR333</li><li>SiS 300 PCI video card</li><li>Labtec-704 USB microphone</li></ul>We performed a simple rendering benchmark that consisted of running baudline with the -reset flag, then recording a full buffers worth of data, pausing, adjusting the <a href="http://www.baudline.com/manual/color_picker.html#color_aperture">Color Aperture</a> window as a remap tweak, and then measuring the FFT transforms/second value in the <a href="http://www.baudline.com/manual/misc.html#stats">Stats</a> window. This simple repeatable test caused baudline to re-render it's spectrogram which is a CPU intensive operation that involves the baudline, X-Server, and kernel code.<br /><br />Now let the testing begin!<br /><br /><span style="font-size:180%;">Fedora 8</span><br />RedHat's latest community release uses the Linux 2.6.23.1-42.fc8 kernel and the Xorg 1.3.0.0 server. Video defaulted to 24 bpp graphics and all the audio devices were found and enabled. Here is a screenshot of baudline running on Fedora 8:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0xeEl8NkXMccGJCYOAkJx95nuEowwH2i0-ybQPe1iqmToOq1Wsnd-1nhJZBPawlJRaiMFzrl19Xq2cQThsbwTDTO4Ji-d7iZAD5-81vkqqA8jqGuMDiVwNZJJqZ2gYb-jgPne/s1600-r/fedora8_screenshot.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1b-roOCnyU1LiELEfQXiA6EQlmmIRiqpQ8dXiWewv736tIgCTLDdeeKDSWWa7YR7JZWnCF8SifqLYxrrMrVDyW8WUfIOF9MVdQAKX9kOp_Sq-ZJ85ejpTa58XmJH8jaNMMxhD/s400/fedora8_screenshot.png" alt="" id="BLOGGER_PHOTO_ID_5138803663459818658" border="0" /></a><br />The main font is wrong, it is bold and mono spaced, but it is readable. The incorrect font caused some of the baudline windows to have spacing and layout issues but this is purely cosmetic. The baudline spectrogram rendering test resulted in 4320 FFTs/second on the Intel P4 CPU and 8000 FFTs/second on the AMD Athlon CPU.<br /><br /><br /><span style="font-size:180%;">openSUSE 10.3</span><br />Novell's latest community release uses the Linux 2.6.22.5-31-default kernel and the Xorg 7.2 server. Video defaulted to 16 bpp graphics and <span style="font-weight: bold;">none</span> of the audio devices were found or enabled. Here is a screenshot of baudline running on openSUSE 10.3:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUn3Kq7QhE1Lat5f3eV4fv1hjzC4AhaQK6EFkOCz1fPjOWLv5SfwOhupl5H_pcKoXHjXUuLl_Jsc_EZnP8KOfXfGCbg6Refay5OgsvP5h_PXXgBsFhGcnakgYdQpcToUVuDn_L/s1600-r/opensuse_10.3_screenshot.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIbAVW74PzQa2UqVic5ncyVGwI66wNiJ-poalyhiAorFpqETGWXi1TVA3AClciUyUr0NjZxMa9k-HxpxJyxyFv-gQ1sToIgjQeyk_hv6yZG8-AEsvZSG6ebyf0cU-hxbc5_Y5Q/s400/opensuse_10.3_screenshot.png" alt="" id="BLOGGER_PHOTO_ID_5138804127316286642" border="0" /></a><br />The main font consists of bizarre symbols and is completely unreadable and unusable. The baudline spectrogram rendering test resulted in 1200 FFTs/second on the Intel P4 CPU and 8400 FFTs/second on the AMD Athlon CPU. Due to less memory bandwidth usage, 16 bpp graphics are usually a lot faster than 24 bpp graphics but that doesn't seem to be the case here.<br /><br /><br /><span style="font-size:180%;">Ubuntu 7.10</span><br />Canonical's latest community release the "Gutsy Gibbon" uses the Linux kernel 2.6.22-14-generic kernel and the Xorg 1.3.0.0 server. Video defaulted to 24 bpp graphics and all the audio devices were found and enabled. Here is a screenshot of baudline running on Ubuntu 7.10:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgAQnKtcMqgF6yHyQi6WoaI72E5KMpNJm8KqfC264LRSXLNig-B-QW48WqIH2BxoAvls084ruGlBIxR_OzIxwKEivy4mSxzkomLrtuSV1m338AL5YKSOsClVYxzMn981WzBSteR/s1600-r/ubuntu_7.10_screenshot.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiydiWd6AOOCBIXUuNTNoeOiMbDMEf8GbgMR0I3k9kNY9qMHsqlmY-9woaU_KOwn8fJWRQrWUQCJ76ef-IEJpaaEm2OqV45r2qhijgPyoIrLEjlmIa6R1De8K9rjqr9_Eet1FY0/s400/ubuntu_7.10_screenshot.png" alt="" id="BLOGGER_PHOTO_ID_5138804775856348354" border="0" /></a><br />Finally a distribution that uses the correct Helvetica font! The baudline spectrogram rendering test resulted in 5400 FFTs/second on the Intel P4 CPU and 8800 FFTs/second on the AMD Athlon CPU.<br /><br /><br /><span style="font-size:180%;">Verdict</span><br />We at <a href="http://www.sigblips.com/">SigBlips</a> recommend using the <span style="font-weight: bold;">baudline signal analyzer</span> with the <span style="font-weight: bold;">Ubuntu 7.10</span> live-CD. It was the only live-CD that used the correct Helvetica font, the test audio devices all worked, and it had the fastest baudline spectrogram rendering. We don't understand how baudline on Ubuntu 7.10 could render 25% faster on the Intel P4 CPU and 4% faster on the AMD Athlon CPU than it could on the Fedora and openSUSE distros. We also don't understand how openSUSE rendering could be so slow on our Intel P4 test machine. Kernel and X-Server compiler optimizations cannot explain this huge performance rift. Some fundamental hardware configuration settings (bus modes?) had to be different.<br /><br />The font and the audio device driver issues probably can be easily fixed after a full install but that wasn't the point of this live-CD battle showdown. We're not sure if the performance issues can be fixed without major re-configuration and compilation.<br /><br />In any case, if you want to use baudline with a Linux live-CD then we recommend <span style="font-weight: bold;">Ubuntu 7.10</span> "Gutsy Gibbon" since it worked the best and it also was the fastest. Not bad for a distro release that's named after a monkey! Now if the distros could only enable <a href="http://www.baudline.com/manual/options.html#backingstore">backing store</a> and include the baudline <a href="http://www.baudline.com/faq.html#input_decoder_helpers">helper apps</a>. (:baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1tag:blogger.com,1999:blog-19780926.post-1150597646696056702006-06-17T18:38:00.000-07:002007-11-30T17:58:15.464-08:00Mosquito Teenager RepellentA company from the UK has created the Mosquito ultrasonic crowd disruptor that generates a high frequency sound that adults are unable to hear. The sound is not loud enough to be harmful but it is extremely annoying to teenagers. According to this BBC news article the Mosquito works quite well at dispersing large crowds of teenagers:<br /><br /><a href="http://www.bbc.co.uk/wiltshire/content/articles/2006/04/04/mosquito_sound_wave_feature.shtml">bbc.co.uk| The Sound that Repels Troublemakers</a><br /><br />The <a href="http://www.baudline.com/">baudline ultrasonic analyzer</a> was used to examine the MP3 Mosquito sound file at the end of the article. The spectrogram is below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/mosquito_sound.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/mosquito_sound.png" alt="" border="0" /></a><br /><br />Background road noise is visible on the left side of the spectrogram. The right side shows a strong tone that sweeps between 15700 and 16500 Hz. The attack and decay slopes have a typical RC shape. The fact that the Mosquito tone is sweeping probably makes it more effective than a stationary tone would be. The human brain is very good at notching out and ignoring constant tones like NTSC or PAL retrace emissions. A moving tone that looks a lot like a siren demands attention.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/play_deck.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/320/play_deck.png" alt="" border="0" /></a><br /><br />Baudline's Play Deck can be used to transform the Mosquito sound into an audible signal for those whose hearing is attenuated above 15kHz. Try slowing the playback down .5X to .25X speed. Or try shifting the signal down about -10000 Hz. The shift slider is equivalent to down mixing which makes it like a radio tuner for audio signals.<br /><br />An ironic twist has developed, the Mosquito ultrasonic tone is now being used by teenagers as a cell phone ring tone. Most schools require that cell phones be turned off in class rooms and since most teachers can't hear that high in frequency the ringing can go undetected.<br /><br />What is next in the ever changing Mosquito ultrasonic technological battlefield? Baudline spectrum analyzers in the classroom? It is a possibility. Contact us if you are interested!<br /><span style=""><br /></span>baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-1149568280961707202006-06-12T14:50:00.000-07:002010-11-12T15:54:31.771-08:00Big Bang AcousticsThe Big Bang is a scientific theory that describes how the universe began from nothingness some 13.7 billion years ago. It started with a silent explosion of matter and energy. This incredible cosmic event was completely silent since there wasn't anything to radiate sound into. After the universe expanded and cooled slightly the physics of pressure were allowed to act. Where there is pressure there can be sound, and the universe began to sing.<br /><br />Two physicists have created slightly different Big Bang acoustic models of the first million years. Both mathematical simulations utilize the cosmic microwave background (CMB) radiation data from the <a href="http://map.gsfc.nasa.gov/">WMAP</a> survey project. This CMB data is a glimpse back into time at the early universe's density variations. The changes in density became clumps and nulls which attracted and reflected pressure variations in the hot primordial gas. This was sound and it had a spectrum. Both mathematical simulations use this base spectrum as a starting point to extrapolate into the future and the past. They attempt to answer the question of what the Big Bang and the expanding universe might of sounded like.<br /><br />The <a href="http://www.baudline.com/">baudline scientific visualizer</a> was used to analyze these two Big Bang acoustic models.<br /><br /><span style="font-size:180%;">Cramer</span><br />John G. Cramer, Professor of Physics at the University of Washington, used a Mathematica program that generated the sound of the universe's first 760,000 years. He used the WMAP microwave data as input and the formula time<sup>2/3</sup> that approximated the rate of growth of the expanding universe. The frequencies of Cramer's simulations have been increased by a factor of 10<sup>26</sup> so that they would be in the audible range.<br /><br />The <b>.wav</b> data files, description of the simulation technique, and an explanation of the physics involved can be found here:<br /><ul><br /><li> <a href="http://staff.washington.edu/seymour/altvw104.html">BOOMERanG and the Sound of the Big Bang paper</a><br /></li><li> <a href="http://faculty.washington.edu/jcramer/BBSound.html">recap, linkbacks, and larger data files</a><br /></li></ul><br /><br />The spectrogram of Cramer's model of the universe's first 760,000 years is below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/cramer_spectro.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/cramer_spectro.png" alt="" border="0" /></a><br /><br />The above spectrogram shows a universe that is rich in harmonic content. It begins as a downward exponential sweep that decays into a hiss like noise at the end. Cramer says in the afterword of his paper that "the spectrum of frequencies at which the universe was acting as a resonator has been well measured by BOOMERanG and more recently by WMAP." The strong spectral peaks correspond to a resonating structure.<br /><br /><br /><span style="font-size:180%;">Whittle</span><br />Mark Whittle, Professor at the University of Virginia, used the WMAP data to model the sound of the universe's first million years. The sound has been transposed up by 50 octaves so that it is in the audible range. A 50 octave increase is equal to the frequency being multiplied by a factor of 2<sup>50</sup>. The sound of the Big Bang was extremely low bass.<br /><br />The <b>.wav</b> data files, description of the simulation technique, and an explanation of the physics involved can be found here:<br /><ul><br /><li> <a href="http://www.astro.virginia.edu/%7Edmw8f/sounds/aas/sounds_web_short_files/v3_document.htm">Primal Scream presentation</a><br /></li><li> <a href="http://www.astro.virginia.edu/%7Edmw8f/sounds/aas/sounds_web_download/index.php">data files, descriptions, diagrams</a><br /></li></ul><br /><br />The spectrogram of Whittle's model of the universe's first 1,000,000 years is below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/whittle_spectro.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/whittle_spectro.png" alt="" border="0" /></a><br /><br />The above spectrogram shows a white noise like universe with harmonic rich nulls that exponentially sweep downward in frequency. At the 500,000 year point the higher frequencies transform into high frequency noise. The Whittle model looks a lot like the Cramer model except instead of pure clean tones there are deep nulls.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/whittle_modes_average.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/whittle_modes_average.png" alt="" border="0" /></a><br /><br />What is interesting about the spectral nulls is that they look a lot like room mode acoustics where the wall dimensions determine which frequencies are boosted and which are attenuated. To carry this room mode analogy a little further would suggest that the exponential downward sweep is the result of the walls being pushed apart until the 500,000 year point where the walls dissolve allowing any built up frequencies to slowly diffuse. The tangential modes of a cube shaped room would match this spectrum almost exactly but the axial and oblique modes, although weaker, would add extra non-harmonic spectral content. Fortunately a sphere symmetry can be modeled as a cube with only tangential modes.<br /><br /><span style="font-size:180%;">Harmonics</span><br />The harmonic structure from the Cramer and Whittle models are very different. In fact they do not have integer ratios and they are not true harmonics at all.<br /><br />The fundamental of the Whittle modes is an oddball null being strangely offset (see spectrum above). All of the other Whittle harmonic nulls line up nicely if a phantom fundamental is used. Try using baudline's <a href="http://www.baudline.com/manual/display.html#harmonic_bars">harmonic bars</a> tool to get an interactive feel for this. Below is a frequency vs. harmonic number plot of the Whittle data that shows a straight line relationship, so the first null is on the line but it is not part of the harmonic progression. Not sure if this anomaly is part of the WMAP data or if it is a simulation artifact. If it is a real and accurate phenomena then it opens up a number of intriguing possibilities and questions.<br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/bb_harmonics.1.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/320/bb_harmonics.0.png" alt="" border="0" /></a><br /><br />The Cramer spectrum at first looks harmonic in structure but closer examination shows an increasing frequency progression that is almost log like. See the average spectrum below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/cramer_harmonics_average.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/cramer_harmonics_average.png" alt="" border="0" /></a><br /><br /><span style="font-size:180%;">Conclusion</span><br />The Cramer and Whittle models are as similar as they are different. They are both interpretations of the same WMAP data and they both demonstrate an almost 14 billion year old sound of the expanding universe. Saying which model is correct is a difficult, if not impossible, task. I can't wait to hear what new data and future physics discoveries might reveal.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-1147046059527176372006-05-07T15:16:00.000-07:002013-05-07T17:10:33.025-07:00VLF whistler echo trainThe <a href="http://www.baudline.com/">baudline VLF analyzer</a> was used to investigate a whistler natural radio emission signal file from the NASA INSPIRE VLF project web page:<br />
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<a href="http://image.gsfc.nasa.gov/poetry/inspire/advanced.html">http://image.gsfc.nasa.gov/poetry/inspire/advanced.html</a><br />
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A whistler is an atmospheric electrical event that has traveled a very long distance. Usually a whistler is sent out into space and is curved back to earth along magnetic field lines. This long distance allows for a large amount of frequency dispersion which causes a lot of curvature. The original sferics wideband pulse is bent into what looks like an exponential downward sweep.<br />
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On the advanced INSPIRE VLF page is a whistler echo train signal file called 6whistechortra.au. It is consists of a primary whistler event and six echoes that are clearly visible in the baudline spectrogram image below:<br />
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<a href="http://photos1.blogger.com/blogger/1113/1965/1600/6whistechorea_spectro.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="http://photos1.blogger.com/blogger/1113/1965/400/6whistechorea_spectro.png" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
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The NASA INSPIRE page says:<br />
<blockquote>
"Echo trains result when the radio wave bounces back and forth between magnetic conjugate points. Each time the signal bounces off the ionosphere, some of the energy leaks down in the lower atmosphere and is heard as a whistler. All of the whistlers in the train are the result of a single lightning stroke. Successive "hops" of the whistler are seen with increasing dispersion time as the distance traveled grows with each bounce."</blockquote>
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This increase in dispersion time can be seen in the spectrogram as the whistler echoes becoming increasingly bent. The lower frequencies travel slower than the higher frequencies. What's interesting is how uniform the dispersion is as a function of frequency. Baudline's <a href="http://www.baudline.com/manual/display.html#periodic_bars">periodicity measurement bars</a> are a perfect tool for investigating this phenomena. A frequency point on the exponential whistler curve is chosen and then the periodicity bars are stretched and dragged to make the measurement. See the baudline spectrogram image below: (click image for a clearer view of the periodicity bars)<br />
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<a href="http://photos1.blogger.com/blogger/1113/1965/1600/6whistechorea_spectro_periodicity.png" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="http://photos1.blogger.com/blogger/1113/1965/400/6whistechorea_spectro_periodicity.png" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
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This delta delay varies from 3.1 seconds at about 5300 Hz to 4.5 seconds at 2200 Hz. The periodicity bar measurements line up perfectly at every frequency so these are true echoes and the delta delay is a function of frequency.<br />
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The speed of light is about 300,000 km/sec (186,000 miles/second). The shortest whistler echo delay at the highest frequency is 3.1 seconds. So if a constant speed of light whistler velocity is assumed, which it isn't, then the distance traveled equals 930,000 km. The Earth - Moon distance is 384,000 km, so the whistler echo distance traveled is roughly equal to a circular path (diameter * pi) to and from the Moon. This is just speculation and without more detailed information about the whistler echo recording it impossible to say for certain that an Earth - Moon circular path is happening. What is known is that the whistler echoes are traveling a very long distance.<br />
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Another interesting observation is by the time of the 4th echo return that the high frequency head of the signal has caught up with the low frequency tail and passed it. The whistler thickness is also increasing with each subsequent echo, so given enough duration, the exponential whistler will dissolve into white noise (equal energy at every frequency) and become spectrally flat.<br />
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Fascinating. A lot of physics is going on in this whistler echo train signal.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-1143854679631454602006-04-08T22:30:00.000-07:002013-05-07T17:10:52.232-07:00VLF sferics, tweeks, whistlersThe <a href="http://www.baudline.com/">baudline VLF analyzer</a> was used to investigate some natural radio emission signal files on the NASA INSPIRE VLF project web page:<br />
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<a href="http://image.gsfc.nasa.gov/poetry/inspire/basic.html">http://image.gsfc.nasa.gov/poetry/inspire/basic.html</a><br />
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The NASA INSPIRE page has audio samples of sferic, tweek, and whistler signals. The sample rate for all of the .au format files is 22050 for an effective Nyquist bandwidth of 11025 Hz.<br />
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<a href="http://photos1.blogger.com/blogger/1113/1965/1600/vlf_color_picker.0.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="http://photos1.blogger.com/blogger/1113/1965/200/vlf_color_picker.jpg" style="cursor: pointer; float: right; margin: 0pt 0pt 10px 10px;" /></a>Fine adjustment of baudline's Color Aperture, Color Picker, and Windowing controls were performed in order to extract the maximum amount of detail from the VLF signal files. The sferic, tweek, and whistler signals used three different color palettes. See the Color Picker window on the right for the respective RGB curves and spectrogram color ramps.<br />
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<span style="font-size: 180%;">Sferics</span><br />
Sferics are caused by lightning and they have spectrums that consist of wideband spectral pulses (horizontal lines). Like a spark gap transmitter, they have infinite bandwidth but the analog capture hardware, digital sampling rate, and atmospheric conduction channel limit this.<br />
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<a href="http://photos1.blogger.com/blogger/1113/1965/1600/vlf_sferic_low.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="http://photos1.blogger.com/blogger/1113/1965/400/vlf_sferic_low.jpg" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
The above spectrogram is the low density sferics data file and it has a number of interesting signal features:<br />
<ul><br />
<li> Multiple sferic lightning pulses stretch from 30 Hz to the Nyquist frequency of 11025 Hz. </li>
<li> A wandering null at around 7000 Hz.</li>
<li> A strong tone at 926 Hz throughout the entire file.</li>
<li> Four weaker tones at 184, 308, 432, 556 Hz look like harmonics but they have a delta spacing of 124 Hz. These solid tones are likely artifacts from the capture hardware.</li>
<li> High frequency wandering tones at 10500 Hz.</li>
</ul>
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<a href="http://photos1.blogger.com/blogger/1113/1965/1600/vlf_sferic.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="http://photos1.blogger.com/blogger/1113/1965/400/vlf_sferic.jpg" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
The above spectrogram is the dense sferics data and it is very similar to the previous sferics data file but it has some interesting feature differences. The sferics have a much higher density, the strong tones below 1000 Hz are gone, and the wandering null is a little lower at 6000 Hz. New is a decreasing bass chirp that is exponential from 100 to 20 Hz. I'm not sure if this bass chirp is real or if it is an artifact of the collection hardware.<br />
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<span style="font-size: 180%;">Tweeks</span><br />
Tweeks are sferics that travel a long distance through the upper atmosphere. Since velocity is a function of wavelength, higher frequencies travel faster than lower frequencies. This phenomena is called dispersion and it manifests itself in the spectrogram as a bending of the straight wideband spectral pulse of the sferic.<br />
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<a href="http://photos1.blogger.com/blogger/1113/1965/1600/vlf_tweeks.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="http://photos1.blogger.com/blogger/1113/1965/400/vlf_tweeks.jpg" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
The spectral "hooks" between 1700 and 1900 Hz are caused by dispersion. Between 250 to 1000 Hz is an interesting flat spectral region that looks like it is unaffected by dispersion. There are also a number of constant tones but at different frequencies in the sferic's spectrogram. These constants tones are likely collection artifacts or RFI.<br />
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<span style="font-size: 180%;">Whistlers</span><br />
A whistler is essentially a sferic that has traveled an even longer distance than a tweek. Usually a whistler is sent out into space and is curved back to earth along magnetic field lines. This longer distance allows for even more dispersion than what a tweek experiences. More distance means more dispersion which causes more curvature. The original sferics wideband pulse is bent into what looks like an exponential downward sweep. See the spectrogram image below:<br />
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<a href="http://photos1.blogger.com/blogger/1113/1965/1600/vlf_whistler.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" src="http://photos1.blogger.com/blogger/1113/1965/400/vlf_whistler.jpg" style="cursor: pointer; display: block; margin: 0px auto 10px; text-align: center;" /></a><br />
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In the above spectrogram image note that some sferics are mixed in with the whistlers to create a compound image. The 10500 Hz wandering tone that was seen in the sferic's spectrogram has returned. There also several constant tones but they are at slightly different frequencies than the tones that were visible in the sferic and tweek images. Again, collection artifacts or RFI are likely to blame.<br />
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In summary; a whistler is a long distance version of a tweek which is a long distance version of a sferic. The VLF signals all start as lightning and velocity dispersion does the rest.baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com0tag:blogger.com,1999:blog-19780926.post-1142634700160786392006-03-17T12:29:00.000-08:002010-11-12T15:51:46.534-08:00Kororaa Linux Xgl LiveCDWe recently downloaded the <a href="http://kororaa.org/">Kororaa</a> Project's Xgl Demo Live CD (Version 0.1) to test out the new Xgl and Compiz technologies. A LiveCD is a simple and painless way of auditioning Linux without the hassle of installation. The transparency, motion, and 3D effects looked extremely cool and we had to give it a try.<br /><br />Our test machine was a 2.0 GHz Pentium 4, 512 MB RAM, GeForce4 MX 440 (64 MB) video card, Sound Blaster 16 PCI card, on-board VIA 8235 sound chip, and a Labtec 704 USB microphone. The Kororaa LiveCD booted up fine but the mouse and window responsiveness was horrifically slow. Something was definitely wrong and our 2 <b>G</b>Hz machine seemed more like a 2 <b>M</b>Hz machine. Restarting with the "kororaa noapic" boot options solved the problem. Our first reaction was "Wow, this is awesome!"<br /><br />Next we fired up <a href="http://baudline.com/">baudline</a>, performed some testing, and the screenshots are below.<br /><br /><span style="font-size:180%;">Opaque Transparency</span><br />With the Compiz window manager the Ctrl+Shift+wheel key/mouse sequence adjusts a window's transparency. Windows can be made partially opaque which can be used in a powerful way with baudline.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/kororaa_green.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/kororaa_green.jpg" alt="" border="0" /></a><br />In the above image; the Tone Generator is creating a FM sine sweep and the aliasing makes for some interesting spectrogram patterns. The Waveform and Histogram windows are visible but since they are transparent they don't block the green spectrogram window. This is a very effective method of maximizing limited screen real estate.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/kororaa_pink.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/kororaa_pink.jpg" alt="" border="0" /></a><br />In the image above; the yellow-pink-blue spectrogram takes up the entire 1024x768 screen (except for the Gnome tool bar at the bottom). The SNR, THD, ENOB, and SFDR distortion measurement windows are transparent and they don't obscure the main display.<br /><br /><span style="font-size:180%;">Spinning Cube</span><br />The virtual workspace is switched by Ctrl+Alt+mouse_button or Ctrl+Alt+arrows key combinations and the green and pink baudline spectrogram sessions spin around in an animated fashion. Makes me dizzy but it is groovy!<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/kororaa_green_pink_cube.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/kororaa_green_pink_cube.jpg" alt="" border="0" /></a><br /><br /><span style="font-size:180%;">Jiggly Jello</span><br />Shake the title bar like a Polaroid picture and the window acts like jiggly jello. Unfortunately the image below doesn't do this feature justice. The motion is clean, smooth, and fluid. Nice physics implementation of the dynamics and the Q damping factor. This feature is a lot of fun to experiment with. (:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/kororaa_green_jello.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/kororaa_green_jello.jpg" alt="" border="0" /></a><br /><br /><span style="font-size:180%;">Observations</span><br />Baudline ran extremely well on Kororaa v0.1, better than on most LiveCDs, but there were some minor quirks:<br /><ol><br /><li> Minor screen and window sizing problems. The Metacity window manager was replaced by Compiz. Some code tuning for Compiz has been added to the baudline TODO list.<br /></li><li> Only 2 audio cards were mounted and our USB audio mic could not be used We think this is a kernel setup limitation.<br /></li><li> Xgl uses an incredible amount of CPU resources and the baudline scrolling speed is slow. The screen is double buffered for the 3D engine and this adds a large overhead. Our 2 GHz machine runs baudline with very high performance (3000 FFTs/seconds with a 100+ FPS scrolling speed). With the Kororaa CD the baudline performance was equivalent to a 200 MHz x86 with a low end graphics card running a traditional X-Server. All of that fancy 3D FX are expensive.<br /></li><li> The default (-reset) baudline performance on Kororaa was 150 FFTs/second and a 30 FPS rate. Most modern machines have no problem rendering a 125 FPS rate. By restarting baudline with the "-backingstore -xslip 1" command line parameters a 50% frame rate improvement to 45 FPS was possible. Xgl uses a double buffer scheme so the -backingstore flag is just taking advantage of what is already running.<br /></li></ol><br /><br /><span style="font-size:180%;">Conclusion</span><br />Kororaa, Xgl, and Compiz are very cool. Compiz could be a little more feature rich such as adding window raising, lowering, stay on top, and stickies. Baudline could use some minor tweaks and tuning for Compiz. Our 2 GHz Pentium 4 and GeForce4 MX 440 machine is really pushing the bottom of the performance envelope while running baudline. Kororaa with a dual core 3.4 GHz P4 and a top of the line Nvidia card would be an amazing machine to run baudline on.<br /><br />For the best Kororaa Xgl performance remember to startup baudline with the following command line:<br /><br />baudline -backingstore -xslip 1baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1tag:blogger.com,1999:blog-19780926.post-1142105579479016762006-03-11T11:32:00.000-08:002007-11-30T18:16:44.371-08:00Yanmar 1-cylinder dieselThis sound clip is a <a href="http://www.yanmarmarine.com/">Yanmar Marine</a> 1-cylinder 4-stroke reciprocating diesel engine at idle. The signal was recorded with a GSM cell phone through the <a href="http://www.audioblogger.com/">Audioblogger</a> system.<br /><br /><div class="audblog"><a href="http://www.audioblogger.com/media/103547/324183.mp3" class="audLink"><img src="http://www.audioblogger.com/media/images/audioblogger.gif" class="audImg" alt="this is an audio post - click to play" border="0" /></a></div><br /><br />The <a href="http://www.baudline.com/fft_analyzer.html">baudline FFT analyzer</a> created the time-frequency spectrogram image below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/yanmar_spectro.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/yanmar_spectro.jpg" alt="" border="0" /></a><br /><br />Baudline's periodicity bars were used to measure an accurate 0.121 second delta between pulses. This works out to 8.26 pulses/second or 496 PPM (Pulses Per Minute). Since the Yanmar is a 4-stroke reciprocating engine, multiplication by 2 will calculate RPM. So: 496 * 2 = 992 RPM which is close to the engine's idle warm-up speed.<br /><br />A section of spectrogram data was copy-n-pasted into the average spectrum window shown below:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://photos1.blogger.com/blogger/1113/1965/1600/yanmar_average.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="http://photos1.blogger.com/blogger/1113/1965/400/yanmar_average.jpg" alt="" border="0" /></a><br /><br />There are two strong peaks of unknown source at 230 Hz and 300 Hz. The exhaust note is an unlikely candidate since it is piped outside the cabin. The air intake and/or the hull resonance are suspected. The recording does not convey the loud pounding sound of the 1-cylinder engine which could be mechanical in nature. The two strong peaks are likely a combination of a couple of the previously mentioned signal sources.<br /><br />Go Eyrie!baudlinehttp://www.blogger.com/profile/01107499364088162542noreply@blogger.com1