dsp_experiments

Placeholder repo for DSP, SDR and ML experiments in C.

Concurrency handled via libdill's channels in conjunction with libwebsocket's ring buffer.

Main dependencies

• libdill
• liquid-dsp
• RtAudio
• SoapySDR
• TensorFlow Lite

For more details regarding dependencies and build process look at GitHub workflow file.

Applications

wbfm_demod

Simple wide band FM radio with mono and stereo demodulation. Expects a file stations.txt with station frequencies. If the file does not exist, it will perform a scan and create one.

flex_tx

Transmitting a flexframe via computer speaker.

flex_rx

Receiving a flexframe via computer microphone.

wav2mel

Turns 16kHz sampled 1s wave files into a Mel scale spectrogram in a form of a PNG.

keywords

Recognizes 17 keywords spoken into a microphone. Some details regarding model training here.

lpc_decoder

Decoded sound from LPC (Linear predictive coding) coefficients

Usage:

./lpc_decoder | play -t raw -b 16 -e signed -c 1 -v 1 -r 11000 -

TODO

• eliminate temporary buffer on stack in link_run
• add more processing blocks