On 09/24/2016 12:34 PM, liverpudd wrote: > Working on the GNURADIO gr-rds to try and find out why it appears to be > finicky with what source drives it.
Unfortunately I don't know anything about RDS. But as strange as this might sound, it almost appears as if the RDS module is configured to use RTL dongle raw I/Q data pairs and not the complex I/Q pairs used by the USRP and HackRF One? > > > > Set up three sources. USRP1, RTL Dongle(NooElec Blue with 0.5ppm TXCO ) > and the HackRF. > > > > Plugged a decent antenna and tuned to R2 (88.3MHz) a nice strong signal. > Whilst the radio works OK with all three sources, the RDS decoding would > only work with the RTL Dongle. > > > > Checked the input IQ level from the RTL dongle and adjusted the input > level to be the same from the USRP1 and the HackRF. No joy – no change > with either the USRP or HackRF decoding the RDS! > > > > Adjusted the Rx frequency 88.3MHz +/- 200KHz. The RDS decoder packed in > beyond +/- 100KHz on the RTL dongle. No joy with either the USRP or > HackRF, no matter what frequency offset I dialled in. > > > > Next adjusted the 1Msps sample rate using a Polyphase Arbitrary > Respampler. Adjusted it from 1Msps to +/- 50Ksps in small increments. > RTL dongle packed in the RDS decode a few Ksps either side of the > nominal centre of 1Msps. No joy from the USRP or HackRF no matter what > sample rate I set it to!!! > > > > Grasping at straws now, I put a phase rotator in line (can’t say I know > what exactly this block does!) but in any case I adjusted the phase by > +/- 5 degs. The RTL dongle packed in the RDS decode at about +/- 0.2 > degs. No joy with the USRP or HackRF, no matter what phase value I set > it to!!! > > > > So current situation is I do not know what is going on. I have adjusted > all that I can to no avail. Any ideas? > > > > Alistair > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
