Initialization of a demodulator object.
classical waveform name ('bpsk', 'qpsk', 'qam16', ...)
Waveform object (created with wf_init)
Input sample frequency
Intermediate (or RF) frequency
Symbol frequency
// QPSK demodulator (NRZ matched filter), // sampling frequency = 1 MHz, IF = 200 KHz, FSYMB = 20 KHz demod = demod_init('qpsk', 1e6, 200e3, 20e3);