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gnuradio-fm

README.md

FM Reception about GNU Radio

  • baseline is a GNU Radio FM reception bench for x86-64
  • baseline-pi is a GNU Radio FM reception bench for Raspberry Pi Zero

These benchmarks are compared with strymons-generated C codes about the same FM reception bench as follows:

  1. First of all, prepare signal file sources for the bench while your PC is connected to HackRF One: 
    e.g.:
$ hackrf_transfer -r sps3072000_s8_30s.pcm -f 82500000 -s 3072000 -g 30 -l 40 -a 0 -n 92160000
$ ffmpeg -f s8 -i sps3072000_s8_30s.pcm -f f32le sps3072000_c32_30s.pcm
$ head --byte=122880000 sps3072000_c32_30s.pcm > sps3072000_c32_5s.pcm
$ head --byte=73728000 sps3072000_c32_30s.pcm > sps3072000_c32_3s.pcm
$ head --byte=49152000 sps3072000_c32_30s.pcm > sps3072000_c32_2s.pcm
$ cp sps3072000_* baseline
$ cp sps3072000_* baseline-pi
  2. Select the strymons pipelines in main.ml for use, then comment out all the other pipelines.
  3. make bench generates the selected FM reception C code to /tmp/generated.c, which is included in bench_main.c (and play_main.c, which is used for playback test).
  4. Adjust the commented-out sources in bench_main.c depending on your purpose.
  5. Compile the code by gcc -Ofast -march=native -W -Wall utils.c bench_main.c, for example, and invoke ./a.out to get a strymonas result.
  6. In baseline(-pi), adjust the commented-out sources in the related files, then invoke make and ./build/gr-fmradio_gnuradio to get a GNU Radio result.

As for the playback test, see the code and comments in play_main.c for more details (especially, about pipeing from hackrf_transfer to ffplay or aplay, for example).

Playback Test on Headless Raspberry Pi

Use PulseAudio.

  • Remote Raspberry Pi:
    1. default-server = <local macine's local IP> in ~/.config/pulse/client.conf
    2. pulseaudio --start
    3. test aplay /usr/share/sounds/alsa/Rear_Center.wav
  • Local machine (the macOS case):
    1. brew services start pulseaudio