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proto17 2022-04-12 21:41:31 -04:00
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@ -177,6 +177,24 @@ Plotting in log scale to make the small variations stick out, and to get a sense
You should see nothing, and then a signal appearing, and then dissapearing before the end of the samples. If you have caught the signal too early, or don't see the end of it, then you need to go back to `baudline` and double check your measurements. If it's still not working, make sure that when you open the file in `baudline` that you specify the correct sampling rate. If that value is wrong, then the time information that `baudline` gives you will be incorrect as well.
At this point you have successfully extracted a single burst. Now it's time to move on to figuring out exactly which sample is the first sample of the burst.
Your MATLAB code should look like this (obviously changing the path, sample start time, and burst duration values)
```
file_path = '../collects/2437MHz_30.72MSPS.fc32';
sample_rate = 30.72e6;
start_time = 2.722209;
burst_duration = 0.00080729;
start_time_samples = round(start_time * sample_rate);
burst_duration_samples = round(burst_duration * sample_rate);
samples = read_complex_floats(file_path, start_time_samples, burst_duration_samples);
figure(1);
plot(10 * log10(abs(samples).^2));
```
[4] https://github.com/gnuradio/gnuradio/blob/main/gr-utils/octave/read_complex_binary.m
[5] https://github.com/proto17/dji_droneid/blob/main/matlab/read_complex_floats.m