I'm not feeding it the stereo pilot. I just use a fractional resampler to resample the few kHz at 19.0kHz/8 --this gives 4 samples/symbol into the DBPSK block.
The spectrum looks roughly correct--a double-humped structure either side of zero. On Tue, 21 Feb 2012 12:27:54 -0500, Andrew Davis wrote: > exactly 19.0kHz/8? > Are you feeding it the stereo pilot or generating your own? > > Have you tried looking at the signal with an FFT scope to see if there > is anything there or if it looks distorted or something? > > On Tue, Feb 21, 2012 at 10:35 AM, wrote: >> I'm having trouble demodulating the RDS signal that comes along with a lot of broadcast FM signals these days. I know that there's "gr-rds" that has already done this, but I wanted to do my own just for personal education. I spent a lot of time yesterday playing with it, and I can't get anything but garbage bits out of the DBPSK demodulator in Gnu Radio. I can't find a freely-available version of the RDS standard, so I've been cribbing from the nearly-impenetrable gr-rds implementation. What I've done is to carve off a few kHz around 57kHz out of the FM demodulator, downconvert to zero Hz, and then resample to exactly 19.0kHz/8, and feed that into a "Digital" DBPSK block, with symbols-per-sample=4. I get nothing but rubbish out the back side of this, even for a strong local signal. Is there something I'm missing in the way the signal gets modulated? -Marcus _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org [1] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio [2] Links: ------ [1] mailto:Discuss-gnuradio@gnu.org [2] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio [3] mailto:mle...@ripnet.com
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