SigDigger VS gnuradio

Local playback? SigDigger is highly recommended: https://batchdrake.github.io/SigDigger/ – it also supports different data modes.

SigDigger is good for a playback of prerecorded full-spectrum files (also called IQ files). Has the time slider, so if you missed anything you can rewind. https://batchdrake.github.io/SigDigger/

For just playing back the wideband recordings SigDigger is a good option.

There is good software for identifying the type of modulation used, and demodulating it, for example SigDigger

SigDigger: https://batchdrake.github.io/SigDigger/ The best thing is that it can move through time and frequency, so you can go back / forward if you need to.

I'd like to add to the answers a fantastic yet relatively unknown piece of software called SigDigger. It is a GUI for suscan. You can run a suscan device server at the raspi and run a remote SigDigger instance. Network bandwidth is minimal because only the FFT and demodulated signal is sent. https://github.com/BatchDrake/SigDigger

https://batchdrake.github.io/SigDigger/

> people downloading telemetry data from space probes

Monitoring JWST transmissions, if doable, might be the next milestone for Ham Radio.

SigDigger

Hi, you can use Sigdigger to perform this task, using FSK inspector. After some tweaking you will be able to display Wefax image. You'll perhaps need to perform line alignment at start. example : https://twitter.com/BatchDrake/status/1216072630698156033?s=20 SigDigger sources As note I can add the purpose of SigDigger is not to decode Wefax, and there are many features ! Hope this can help

In gr-dtv transmitter examples for Gnuradio, I see some times people use a resampler block before the RF hardware sink. Say our sampling rate is ~9.14Msps which satisfies the Nyquist criterion because our samples are complex numbers.

2.1. Thanks for that tip, I forgot that I was able to check the source code of the WBFM Receive block. As you have said, there are mostly the same. There are some differences between how values are picked. The WBFM Receive block would be a synonym of Quadrature demod => Fir Filter (decimation => Low pass filter) => FM Deemphasis. 2.3. My question there is why 10 and not 20 or 100. I understand that the idea is to reduce the sample rate asap, but what I don't understand is why those values were picked and how can I understand what would be the "correct" or "best" value. 2.4. I'm not fully understanding what you said. If I check the WB FM recieve source code the values that are supplied as the cutoff freq and transition width of the Low pass filter differ from the one of the example. The webfm would apply a sample rate / decimation / 2 - sample rate / decimation / 32 as a cutoff freq and a sample rate / decimation / 32 as a transition transition width. Calculating those values would end up in different that the ones supplied in this second example. Again, is there a rule of thumb to pick these values?.

Gaussian filter is used only on the tx side, so specifying bt in the receiver makes no sense. Take a look at gfsk mod/demod blocks implementation: https://github.com/gnuradio/gnuradio/blob/master/gr-digital/python/digital/gfsk.py

GNU Radio

Here's the filter coefficients used for the GNU-Radio interpolator block to get you started. This is a 7th order interpolator (i.e., 8 FIR taps) with very good performance. Each "row" of the array sets the delay in steps of sample_time / 128.

From their README: “open-source software development toolkit that provides signal processing blocks to implement software radios.” https://github.com/gnuradio/gnuradio