How to demodulate an FSK signal?

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egor_spk2016-04-24 23:12:26

Signal processing

egor_spk, 2016-04-24 23:12:26

Hello. I analyze the code of this project: https://github.com/kamalmostafa/minimodem .
And I can not understand the following things for myself:
1) How to determine the carrier by receiving the signal spectrum (fsk.c -> fsk_detect_carrier)?
2) How is noise calculated (fsk.c -> fsk_frame_analyze)?
3) When calculating the probability of a recognized signal, the author uses the concept of divergence, but how he calculates it is also not clear.
Strongly do not kick, far from DSP.