I would like to add some type of carrier recovery to the GMSK demodulator in GNU Radio, however I am having a bit of trouble getting something implemented that works properly. I have tried using gr.costas_loop_cc to add a costas loop for carrier recovery, but I am not quite sure how to calculate the parameters (alpha, beta, fmax, fmin, costas_order). Can anyone offer some insight into how to calculate these numbers? Some nominal parameters to consider would be symbol rate of 31.25 kHz, using the USRP at max decimation (256) which results in 8 samples per symbol (250 kHz) sampling. I'm using the TVRX daughtercard. Thanks in advance for any help! Regards, John -- View this message in context: http://www.nabble.com/GMSK-carrier-recovery-tf3351... Sent from the GnuRadio mailing list archive at Nabble.com.
on 2007-03-05 21:21
on 2007-03-06 00:22
Hi John, I am interested in your problem. Could you give some more details about the GMSK signal you are looking at? For example what is the modulation index and what is the time bandwidth product of the pulse? Tim