Distorted signals recorded by the Audio App

[flux242]

Describe the bug.

As nobody reacted on discord I'm repeating the same question here. Don't know if that's actually a bug or me not using device correctly or some hw problem

Hello, I have portapack for couple of days now and was trying to decode pocsag and it couldn't decode messages. Then I started the Audio app and recorded the POCSAG signal, then I recorded the same signal using gqrx with the same IF and VGA values. Portapack recording seems distorted and I don't understand what to do with it. Any hints? Was using NFM 11k portapack bw and 10k gqrx bw. Preamp was disable

Here are the pictures of the audio recorded https://imgur.com/a/BAVEF6K

Reproduction

Start Audio app, set IF to 16, VGA to 24, tune to the local POCSAG frequency (466.075 here) and record the audio

Expected behavior

Recrorded signal should look like the one recorded with gqrx

Environment/versions

2.0.1

Anything else?

No response

[Radiomix2000]

I found similar issue with POCSAG. It looks like the transmitted signal playing speed is accelerated 2 times. Possibly interpolation/decimation/samplerate is somewhere broken.

[flux242]

A AM OOK signal recorded with mayhem and gqrx. Obviously, a high pass filter is used instead of a low pass one somewhere in the demodulation chain. So NFM, AM demodulation is broken