This repository is a loose collection of SDR, analog and digital modulation scripts.
Contains SDR stuff. Highlights:
fm1.py: FM mono receiver. Check the scripts 'python_fm_mono' and 'python_fm_rt' for usage.
fm1s.py: FM stereo receiver. Client scripts are 'python_fm_stereo' and 'python_fm_rt_stereo'.
fastfm.pyx: FM stereo decoder with PLL written in Cython. Used by fm1s.py in fast mode. Compile the module with 'make' and run fm1s.py with -o if your machine can't decode stereo FM in realtime.
filters.py: Pure Python implementations of common filters: low-band, high-band, passband, FM stereo deemphasis, and decimator.
power.py/power: Show signal strength of band using RTL-SDR. Note that unit is dbFS, which is relative and not relatable to absolute units like dBmV/m or dBm.
nfm.py: Records multiple narrow FM channels, like VHF or Talkabout, with squelch. Client scripts: talkabout and vhf.
dsd-gqrx: Gets UDP audio packets from GQRX or other SDR software, and feeds into DSD to decode digital radio (DMR et al). DSD must be installed in your system, version 1.7 or better is recommended (had no luck decoding DMR with 1.6).
dsd-rtl-save: usess rtl_fm instead of GQRX as front-end. Saves audio as $FREQ.wav.
The 'test_samples' folder contains raw I/Q data from RTL-SDR to test scripts without the need of a dongle (and a live radio station).
am.py: Records multiple AM or SSB channels, like aviation and CB.
The 'aprs' folder contains APRS scripts, mostly ones that use RTL-SDR as radio and Direwolf as decoder.
The 'mesh' folder contains mesh network simulation, that I am working on as part of a LoRa-based ham project.
The 'modul' folder contains old and naïve implementations of a number of modulation and demodulation techniques, both analog and digital.