Hello, I'm using the gr::analog::pll_carriertracking_cc() block to track a very stable signal of which I don't know the exact frequency and of which I want to detect (small!) phase oscillations.
In my tests I discovered that the tracked signal has a residual phase modulation that I would not expect to find. I tried a simple test, very similar to the qa test for the block, and indeed I found that even for a constant frequency input signal the output has some residual phase oscillations. The amplitude of the oscillations depends on the pll bandwidth and on the frequency of the input signal, of the order of mrad for this examples (qa_pll_carriertracking.py). I need to get rid of those oscillations because they mask the phase signal I want to measure. I'm going to investigate the issue further, but does anyone have an idea about where those may come from? I suspect the digital oscillator may introduce some numeric error that may explain them, but they seem quite big... Cheers, Daniele _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
