Hi all,
I'm trying to figure out what the test_corr_and_sync example (located .../src/gnuradio/gr-digital/examples/demod/test_corr_and_sync.grc) is showing me. I see the tags added by the correlator, but they seem to jump around a bit. If I add some timing offset with the slider, I don't see much relation to that and the time_est tag value. I can't find any correlation between the four sliders and any of the tag values.
I also see the constellation being smeared out considerably. It looks to me like the rrc_taps variable might be set incorrectly. The number of taps portion of the filter does not match the constellation modulator number of taps (5*sps vs 11*sps). Though changing this to what I believe is correct does not help the smear all that much. Shrug.
If this is working as intended, what net effect does this have on the pfb_sync and costas filters? Is it a considerable boost in sync performance?