Michael, Marcus, Right now, the code is a work in progress so I haven't made a git repository out of it. However, I have it on dropbox. Here's the link to the source folder(p1_detector_impl.cc is the source in question):
*https://www.dropbox.com/sh/blfmxsaidrkh28t/AAArp8IHavzCGFlJs6E6-Hrca?dl=0 <https://www.dropbox.com/sh/blfmxsaidrkh28t/AAArp8IHavzCGFlJs6E6-Hrca?dl=0>* As for Marcus's question regarding why use a circular buffer? It isn't exactly a circular buffer now, but more of a shift register. The reasons are as follows: 1. I needed running sums for correlations in B-Branch and C-Branch correlators, and Power Sums (for average power) to normalize them. Then, I also needed a finite delay buffer to delay the C-Branch before it gets multiplied with the B-Branch. 2. It kind of carried over from the last implementation attempt: Assertion: If a peak is detected after the multiplication, the signal boundary is 1024 samples behind that index. Once the correlations crossed a threshold (the code entered state=1), *instead of looking back, I then needed to look forward to see if it were a false alarm or not*. So, I compute the correlations across all available current inputs and try to find a peak. If a peak is found, enter state=3 where we do a correlation with the carrier distribution sequence after FFT of all signals of interest. So, here, I not only needed just the single value (the running sum), but the entire state of the delay register and the B-Branch correlator. I hope I am able to convey the reason for implementing one myself. In the current implementation, I make an assumption that the threshold is so high that only the desired signals would cross it (100-150 times the average). So I skip the state=1 logic and directly go into state=2 logic of aggressively doing a FFT and correlation with the CDS. However, I don't think this has a binding on the incoming values. Use of buffers is internal to the implementation, I am just printing out the current values as they arrive. For example, when I use the test file in 'make test', the values fed in are non-zero from t=1. However, when using gnuradio-companion, t=56 line is where the file source starts yielding proper inputs to my block. The stdout prints of the initial values in both GRC and make tests are attached. The gnuradio-companion version has my first 55 samples zeroed and the 56th input onward is then same for both. P.S.: The source stream is a 1.2 Gigs file, so haven't uploaded it. If you'd like I can do that too. It was generated by using a DVB-T2 Tx block and writing the output into a file sink. Warm regards, Anshul Thakur On 31 March 2018 at 02:27, Müller, Marcus (CEL) <muel...@kit.edu> wrote: > Hi Anshul, > > you shouldn't have to have your own buffer for a running sum – can you > explain why you're doing that? > A running sum can trivially be implemented with the IIR filter block > with Feed-Forward taps (1,) and Feed-back taps (1,0)! > Where does in a running sum does a division take place? > > > (a) Why am I getting the initial zero samples from the file block in > > gnuradio_companion and non-zero values when using a vector_source in > > unit tests? > > If these zeros are not in the file you're reading, your block has a > bug! > > > > (b) What can I do about it (here specifically as a fix to the > > situation, and a general guideline to always remember)? > > good question, but we'd need to know your code, your motivation for a > circular buffer, and why you're implementing a running sum yourself! > > Best regards, > Marcus > > On Fri, 2018-03-30 at 23:19 +0530, Anshul Thakur wrote: > > Hi, > > > > I used a circular buffer of finite size to keep the past 'N' power > > values of the sample stream in my block as a part of creating a > > running sum. This buffer is initialized to 0 in the constructor. > > The running sum of powers is used to compute the average power used > > in computing signal correlation. > > > > I have a capture stream (cfile) to test the operation of the block. > > The test case uses a vector_source_c block to read the contents of > > the file into memory. The unit tests pass without error. > > > > However, when I use the block in a flowgraph in that reads the same > > file from a file source block gnuradio_companion, I am getting the > > first few sample values as 0 which cause a divide by zero > > problem. This messes up the rest of the running sum. I don't want to > > put an 'if' block that checks for the zero condition as it is not > > expected that a device/stream would ever spit out zero values. > > > > (a) Why am I getting the initial zero samples from the file block in > > gnuradio_companion and non-zero values when using a vector_source in > > unit tests? > > > > (b) What can I do about it (here specifically as a fix to the > > situation, and a general guideline to always remember)? > > > > I am using GNURadio version 3.7.12. > > > > Regards, > > Anshul > > _______________________________________________ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
t: 1 In (0,0) Current: (0,0) t: 1 Correlation: nan Avg: 0 t: 2 In (0,0) Current: (0,0) t: 2 Correlation: nan Avg: nan t: 3 In (0,0) Current: (0,0) t: 3 Correlation: nan Avg: nan t: 4 In (0,0) Current: (0,0) t: 4 Correlation: nan Avg: nan t: 5 In (0,0) Current: (0,0) t: 5 Correlation: nan Avg: nan t: 6 In (0,0) Current: (0,0) t: 6 Correlation: nan Avg: nan t: 7 In (0,0) Current: (0,0) t: 7 Correlation: nan Avg: nan t: 8 In (0,0) Current: (0,0) t: 8 Correlation: nan Avg: nan t: 9 In (0,0) Current: (0,0) t: 9 Correlation: nan Avg: nan t: 10 In (0,0) Current: (0,0) t: 10 Correlation: nan Avg: nan t: 11 In (0,0) Current: (0,0) t: 11 Correlation: nan Avg: nan t: 12 In (0,0) Current: (0,0) t: 12 Correlation: nan Avg: nan t: 13 In (0,0) Current: (0,0) t: 13 Correlation: nan Avg: nan t: 14 In (0,0) Current: (0,0) t: 14 Correlation: nan Avg: nan t: 15 In (0,0) Current: (0,0) t: 15 Correlation: nan Avg: nan t: 16 In (0,0) Current: (0,0) t: 16 Correlation: nan Avg: nan t: 17 In (0,0) Current: (0,0) t: 17 Correlation: nan Avg: nan t: 18 In (0,0) Current: (0,0) t: 18 Correlation: nan Avg: nan t: 19 In (0,0) Current: (0,0) t: 19 Correlation: nan Avg: nan t: 20 In (0,0) Current: (0,0) t: 20 Correlation: nan Avg: nan t: 21 In (0,0) Current: (0,0) t: 21 Correlation: nan Avg: nan t: 22 In (0,0) Current: (0,0) t: 22 Correlation: nan Avg: nan t: 23 In (0,0) Current: (0,0) t: 23 Correlation: nan Avg: nan t: 24 In (0,0) Current: (0,0) t: 24 Correlation: nan Avg: nan t: 25 In (0,0) Current: (0,0) t: 25 Correlation: nan Avg: nan t: 26 In (0,0) Current: (0,0) t: 26 Correlation: nan Avg: nan t: 27 In (0,0) Current: (0,0) t: 27 Correlation: nan Avg: nan t: 28 In (0,0) Current: (0,0) t: 28 Correlation: nan Avg: nan t: 29 In (0,0) Current: (0,0) t: 29 Correlation: nan Avg: nan t: 30 In (0,0) Current: (0,0) t: 30 Correlation: nan Avg: nan t: 31 In (0,0) Current: (0,0) t: 31 Correlation: nan Avg: nan t: 32 In (0,0) Current: (0,0) t: 32 Correlation: nan Avg: nan t: 33 In (0,0) Current: (0,0) t: 33 Correlation: nan Avg: nan t: 34 In (0,0) Current: (0,0) t: 34 Correlation: nan Avg: nan t: 35 In (0,0) Current: (0,0) t: 35 Correlation: nan Avg: nan t: 36 In (0,0) Current: (0,0) t: 36 Correlation: nan Avg: nan t: 37 In (0,0) Current: (0,0) t: 37 Correlation: nan Avg: nan t: 38 In (0,0) Current: (0,0) t: 38 Correlation: nan Avg: nan t: 39 In (0,0) Current: (0,0) t: 39 Correlation: nan Avg: nan t: 40 In (0,0) Current: (0,0) t: 40 Correlation: nan Avg: nan t: 41 In (0,0) Current: (0,0) t: 41 Correlation: nan Avg: nan t: 42 In (0,0) Current: (0,0) t: 42 Correlation: nan Avg: nan t: 43 In (0,0) Current: (0,0) t: 43 Correlation: nan Avg: nan t: 44 In (0,0) Current: (0,0) t: 44 Correlation: nan Avg: nan t: 45 In (0,0) Current: (0,0) t: 45 Correlation: nan Avg: nan t: 46 In (0,0) Current: (0,0) t: 46 Correlation: nan Avg: nan t: 47 In (0,0) Current: (0,0) t: 47 Correlation: nan Avg: nan t: 48 In (0,0) Current: (0,0) t: 48 Correlation: nan Avg: nan t: 49 In (0,0) Current: (0,0) t: 49 Correlation: nan Avg: nan t: 50 In (0,0) Current: (0,0) t: 50 Correlation: nan Avg: nan t: 51 In (0,0) Current: (0,0) t: 51 Correlation: nan Avg: nan t: 52 In (0,0) Current: (0,0) t: 52 Correlation: nan Avg: nan t: 53 In (0,0) Current: (0,0) t: 53 Correlation: nan Avg: nan t: 54 In (0,0) Current: (0,0) t: 54 Correlation: nan Avg: nan t: 55 In (0,0) Current: (0,0) t: 55 Correlation: nan Avg: nan t: 56 In (0,0) Current: (0.114258,-0.0864258) t: 56 Correlation: 0 Avg: nan t: 57 In (0,0) Current: (0.100586,-0.0454102) t: 57 Correlation: 0 Avg: nan t: 58 In (0,0) Current: (0.124512,-0.15332) t: 58 Correlation: 0 Avg: nan t: 59 In (0,0) Current: (0.293457,-0.193848) t: 59 Correlation: 0 Avg: nan t: 60 In (0,0) Current: (0.267578,0.0170898) t: 60 Correlation: 0 Avg: nan t: 61 In (0,0) Current: (-0.257324,0.100586) t: 61 Correlation: 0 Avg: nan t: 62 In (0,0) Current: (0.0385742,-0.078125) t: 62 Correlation: 0 Avg: nan t: 63 In (0,0) Current: (0.211914,-0.0322266) t: 63 Correlation: 0 Avg: nan t: 64 In (0,0) Current: (0.0200195,0.0834961) t: 64 Correlation: 0 Avg: nan t: 65 In (0,0) Current: (0.130859,0.0551758) t: 65 Correlation: 0 Avg: nan t: 66 In (0,0) Current: (-0.11377,-0.0424805) t: 66 Correlation: 0 Avg: nan
Start testing: Mar 31 08:28 IST ---------------------------------------------------------- 1/2 Testing: test_dvbt2 1/2 Test: test_dvbt2 Command: "/bin/sh" "/home/craft/Dropbox/PhD/SDR/GRC/gr-dvbt2/build/lib/test_dvbt2_test.sh" Directory: /home/craft/Dropbox/PhD/SDR/GRC/gr-dvbt2/build/lib "test_dvbt2" start time: Mar 31 08:28 IST Output: ---------------------------------------------------------- . <end of output> Test time = 0.10 sec ---------------------------------------------------------- Test Passed. "test_dvbt2" end time: Mar 31 08:28 IST "test_dvbt2" time elapsed: 00:00:00 ---------------------------------------------------------- 2/2 Testing: qa_p1_detector 2/2 Test: qa_p1_detector Command: "/bin/sh" "/home/craft/Dropbox/PhD/SDR/GRC/gr-dvbt2/build/python/qa_p1_detector_test.sh" Directory: /home/craft/Dropbox/PhD/SDR/GRC/gr-dvbt2/build/python "qa_p1_detector" start time: Mar 31 08:28 IST Output: ---------------------------------------------------------- 136383191 In constructor t: 1 In (0,0) Current: (-0.16748,-0.0776367) t: 1 Correlation: 0 Avg: 0 t: 2 In (0,0) Current: (-0.0864258,-0.109863) t: 2 Correlation: 0 Avg: 0 t: 3 In (0,0) Current: (-0.144531,0.0864258) t: 3 Correlation: 0 Avg: 0 t: 4 In (0,0) Current: (-0.0581055,0.043457) t: 4 Correlation: 0 Avg: 0 t: 5 In (0,0) Current: (0.484863,-0.0273438) t: 5 Correlation: 0 Avg: 0 t: 6 In (0,0) Current: (0.171875,0.185547) t: 6 Correlation: 0 Avg: 0 t: 7 In (0,0) Current: (0.0268555,0.133789) t: 7 Correlation: 0 Avg: 0 t: 8 In (0,0) Current: (0.0405273,-0.0151367) t: 8 Correlation: 0 Avg: 0 t: 9 In (0,0) Current: (-0.39502,0.0942383) t: 9 Correlation: 0 Avg: 0 t: 10 In (0,0) Current: (-0.0869141,0.090332) t: 10 Correlation: 0 Avg: 0 t: 11 In (0,0) Current: (0.163086,0.0136719) t: 11 Correlation: 0 Avg: 0 t: 12 In (0,0) Current: (0.104492,-0.019043) t: 12 Correlation: 0 Avg: 0 t: 13 In (0,0) Current: (-0.0424805,0.00195312) t: 13 Correlation: 0 Avg: 0 t: 14 In (0,0) Current: (-0.296387,-0.0620117) t: 14 Correlation: 0 Avg: 0 t: 15 In (0,0) Current: (-0.12793,-0.23584) t: 15 Correlation: 0 Avg: 0 t: 16 In (0,0) Current: (0.157227,-0.126465) t: 16 Correlation: 0 Avg: 0 t: 17 In (0,0) Current: (0.0126953,0.105469) t: 17 Correlation: 0 Avg: 0 t: 18 In (0,0) Current: (0.00830078,0.219238) t: 18 Correlation: 0 Avg: 0 t: 19 In (0,0) Current: (0.10498,0.378906) t: 19 Correlation: 0 Avg: 0 t: 20 In (0,0) Current: (-0.0395508,0.11377) t: 20 Correlation: 0 Avg: 0 t: 21 In (0,0) Current: (-0.0112305,-0.284668) t: 21 Correlation: 0 Avg: 0 t: 22 In (0,0) Current: (-0.0712891,-0.0488281) t: 22 Correlation: 0 Avg: 0 t: 23 In (0,0) Current: (-0.18457,0.193359) t: 23 Correlation: 0 Avg: 0 t: 24 In (0,0) Current: (0.125,-0.111328) t: 24 Correlation: 0 Avg: 0 t: 25 In (0,0) Current: (0.0244141,-0.20166) t: 25 Correlation: 0 Avg: 0 t: 26 In (0,0) Current: (-0.0507812,0.181152) t: 26 Correlation: 0 Avg: 0 t: 27 In (0,0) Current: (0.319336,0.117188) t: 27 Correlation: 0 Avg: 0 t: 28 In (0,0) Current: (0.102051,-0.24707) t: 28 Correlation: 0 Avg: 0 t: 29 In (0,0) Current: (-0.0668945,0.081543) t: 29 Correlation: 0 Avg: 0 t: 30 In (0,0) Current: (0.14209,0.342285) t: 30 Correlation: 0 Avg: 0 t: 31 In (0,0) Current: (0.0673828,0.0957031) t: 31 Correlation: 0 Avg: 0 t: 32 In (0,0) Current: (0.0380859,-0.111328) t: 32 Correlation: 0 Avg: 0 t: 33 In (0,0) Current: (0.118164,-0.0585938) t: 33 Correlation: 0 Avg: 0 t: 34 In (0,0) Current: (0.0878906,0.117188) t: 34 Correlation: 0 Avg: 0 t: 35 In (0,0) Current: (0.0419922,0.129395) t: 35 Correlation: 0 Avg: 0 t: 36 In (0,0) Current: (0.0419922,-0.00390625) t: 36 Correlation: 0 Avg: 0 t: 37 In (0,0) Current: (0.140137,0.000976562) t: 37 Correlation: 0 Avg: 0 t: 38 In (0,0) Current: (-0.0581055,0.0708008) t: 38 Correlation: 0 Avg: 0 t: 39 In (0,0) Current: (-0.213379,0.125977) t: 39 Correlation: 0 Avg: 0 t: 40 In (0,0) Current: (-0.0307617,0.121582) t: 40 Correlation: 0 Avg: 0 t: 41 In (0,0) Current: (-0.043457,-0.0444336) t: 41 Correlation: 0 Avg: 0 t: 42 In (0,0) Current: (-0.0107422,-0.059082) t: 42 Correlation: 0 Avg: 0 t: 43 In (0,0) Current: (0.152832,-0.0253906) t: 43 Correlation: 0 Avg: 0 t: 44 In (0,0) Current: (-0.0424805,-0.0849609) t: 44 Correlation: 0 Avg: 0 t: 45 In (0,0) Current: (-0.0864258,-0.0258789) t: 45 Correlation: 0 Avg: 0 t: 46 In (0,0) Current: (0.112305,0.0488281) t: 46 Correlation: 0 Avg: 0 t: 47 In (0,0) Current: (0.112305,-0.103516) t: 47 Correlation: 0 Avg: 0 t: 48 In (0,0) Current: (-0.00439453,0.113281) t: 48 Correlation: 0 Avg: 0 t: 49 In (0,0) Current: (0.117676,0.132324) t: 49 Correlation: 0 Avg: 0 t: 50 In (0,0) Current: (0.206543,-0.0297852) t: 50 Correlation: 0 Avg: 0 t: 51 In (0,0) Current: (0.0449219,0.154297) t: 51 Correlation: 0 Avg: 0 t: 52 In (0,0) Current: (0.110352,0.0512695) t: 52 Correlation: 0 Avg: 0 t: 53 In (0,0) Current: (-0.0170898,-0.0288086) t: 53 Correlation: 0 Avg: 0 t: 54 In (0,0) Current: (-0.0527344,0.194824) t: 54 Correlation: 0 Avg: 0 t: 55 In (0,0) Current: (0.189941,0.0537109) t: 55 Correlation: 0 Avg: 0 t: 56 In (0,0) Current: (0.114258,-0.0864258) t: 56 Correlation: 0 Avg: 0 t: 57 In (0,0) Current: (0.100586,-0.0454102) t: 57 Correlation: 0 Avg: 0 t: 58 In (0,0) Current: (0.124512,-0.15332) t: 58 Correlation: 0 Avg: 0 t: 59 In (0,0) Current: (0.293457,-0.193848) t: 59 Correlation: 0 Avg: 0 t: 60 In (0,0) Current: (0.267578,0.0170898) t: 60 Correlation: 0 Avg: 0 t: 61 In (0,0) Current: (-0.257324,0.100586) t: 61 Correlation: 0 Avg: 0 t: 62 In (0,0) Current: (0.0385742,-0.078125) t: 62 Correlation: 0 Avg: 0 t: 63 In (0,0) Current: (0.211914,-0.0322266) t: 63 Correlation: 0 Avg: 0 t: 64 In (0,0) Current: (0.0200195,0.0834961) t: 64 Correlation: 0 Avg: 0 t: 65 In (0,0) Current: (0.130859,0.0551758) t: 65 Correlation: 0 Avg: 0 t: 66 In (0,0) Current: (-0.11377,-0.0424805) t: 66 Correlation: 0 Avg: 0
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