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thomastoye / dmr-from-scratch

An attempt to decode Digital Mobile Radio (DMR) from scratch in idiomatic Python
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How to deal with IQ samples? #2

Open xu997871764 opened 2 years ago

xu997871764 commented 2 years ago

This program works well, but it can not handle IQ samples directly. In assets folder, you mention that [SDRSharp_20160101_231914Z_12kHz_real.wav] is made by decoding 4FSK and rrcos. I tried many methods from the Internet, but I still can not make correct real samples from IQ samples. Could you please tell me how to deal with IQ samples? Appreciate.

USA-RedDragon commented 1 year ago

@thomastoye same question. It doesn't seem like SDRSharp_20160101_231914Z_12kHz_real.wav is actually the demodulated IQ signal, as the duration of the files differs greatly. I'm struggling to get any other samples to work right, and I'm starting to think this is because SDRSharp_20160101_231914Z_12kHz_real.wav is an idealized sample. Any clarification to this would be greatly appreciated

xu997871764 commented 1 year ago

I have solved this question. That SDRSharp_20160101_231914Z_12kHz_real.wav is actualld generated by SDRSharp_20160101_231914Z_12kHz_IQ.wav using FM demod. See that page at 15. End-to-end example: https://pysdr.org/content/rds.html

thomastoye commented 1 year ago

Hi @xu997871764, you are right. Indeed the sample in this repository is demodulated and "hearable" if you run it through an audio player.