Possibly a stupid question, but might help me better understand how the gnuradio scheduler works:
my objective is to make a low cost phase-referenced radiofrequency interferometer using two DVB-T dongles. Since I have observed that the PLL inside each dongle induces slow phase drift, I want to use an external RF switch to monitor a known (50 MHz) reference oscillator feeding both dongles, and then monitor the unknown signal. Current switching rate is about 50 Hz triggered by an external generator (which also synchronizes other events of the experiment, not relevant to this post). My idea for synchronizing the post-processing of phase extraction was to record on the one hand the two DVB-T dongle data flow (this I know works), and on the other hand the sound card microphone connected to the switch trigger signal. This process is summarized in the grc flowchart at http://jmfriedt.sequanux.org/damien_grc.png However, the sound card output shows a result completely out of sync with the phase measurements. I understand that the sound card and DVB-T dongles do not share the same clock sources, but considering the huge decimation factor (48*32 kHz for the DVB-T, 48 kHz for the sound card, and a phase output recorded at about 0.5 to 5 kHz, not shown on this grc chart), I would have expected the trigger signal to be more or less synchronized with the DVB-T outputs, which is not at all the case. Is the gnuradio scheduler unable to interleave two data sources as different as a sound card and the USB data flow from the two DVB-T dongles ? Is there a way I might tune my flowchart to achieve the expected result ? Thanks, JM -- JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 Besancon, France _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio