Dne Thursday 07 June 2012 ob 22:38:51 je Alexandru Csete napisal(a): > On Thu, Jun 7, 2012 at 10:27 PM, Gasper Zejn <z...@kiberpipa.org> wrote: > > Dne Thursday 07 June 2012 ob 21:59:24 je Alexandru Csete napisal(a): > >> On Thu, Jun 7, 2012 at 11:13 AM, Gasper Zejn <z...@kiberpipa.org> wrote: > >> > a bit more on my setup: I'm using funcube as a source, tuned to > >> > 868.48M, LNA gain 20dB, mixer gain 12dB, connected to simple squelch > >> > (threshold=-40dB, alpha=1) and on to quadrature demodulation block. > >> > This block then outputs clearly visible binary signal when funcube is > >> > initialized properly. > >> > > >> > The observed signal is rated at 20kbit, so it's a bit on the upper > >> > limit of what Funcube can do, but it's still possible to get a decent > >> > read. It's a burst of bits every 5s from a power meter[1][2], and the > >> > first part is a lead- in and stays the same even if readings change. > >> > > >> > Somewhere in the funcube source block there is obviously something > >> > wrong with initialization. Running qthid after starting flow changes > >> > something in funcube that makes it output correct signal. Using this > >> > and the fact, that the lead-in stays the same, it seems the "corrupt" > >> > signal (viewed in scope) is sometimes a derivative of the expected > >> > signal - most of the time on zero, with spikes up and down on > >> > transitions, with timing corresponding to transitions in expected > >> > signal. > >> > >> Do you have the same frequency correction value in both qthid and the > >> FCD source? If yes, what is the value? > >> > >> Alex > > > > Ahh, yes. I had 0 in my flow and qthid was -120. > > > > So sorry to waste your precious time. > > No problem, time wasn't wasted since there is actually a bug in the > init part of fcd_source_c.xml: it checks whether correction is 115 > whereas it should check -120, but this bug is only triggered if your > initial correction is set to 115 ppm. > > I also realized that I never added 1 Hz resolution to qthid. > > Alex >
Ah, that explains something then. I remember experimenting with correction, but I was looking at fcd_source_c.xml and, influenced by it, used 120 instead of -120, therefore not getting correct result and dismissing it as not the right parameter to tune. Any way, it's allways nice to see bugs fixed. :) Gasper _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
