I am currently trying to fix an old GNURadio Python script which uses digital.dbpsk_demod, but having a trouble with the frequency / timing / phase correction loop bandwidth parameters. When I set them to non-zero values (5/1000 ~ 6.28/100) , and start the transmitter a few seconds AFTER the receiver, the receiver fails to correctly demodulate the incoming data. It does not happen if I start the transmitter before starting the receiver.
What am I doing wrong here, and what should I do to fix the problem?
UHD Source --> DBPSK Demod --> digital.demod_pkts --> File Sink
self.demodulator = digital.dbpsk_demod(samples_per_symbol=4,excess_bw=0.35,freq_bw=1e-3,phase_bw=1e-3,timing_bw=1e-3,mod_code="gray",verbose=False,log=False)
self.modulator = digital.dbpsk_mod(samples_per_symbol=4,excess_bw=0.35,mod_code="gray",verbose=False,log=False)
Kyeong Su Shin