Hi to all. I want to test if the block Correlate and Sync improves my GFSK receiver, so I started modifying ./gr-digital/examples/demod/test_corr_and_sync.grc .
1) I replaced the BPSK modulator (with rrc filter) by a Chunks to Symbols [-1,+1] followed by a Interpolating FIR with gaussian taps. 2) I replaced the matched filter taps for Correlate and Sync and Polyphase Clock Sync with the ones I think are correct BUT OBVIOUSLY ARE NOT [<-- help needed here]. 3) I eliminated frequency offset and Costas Loop because I believe they are not applicable after a FM demodulation (which I did not included in this first exploration). (Flowgraph attached) Things I observe: * Correlate and Sync detects preamble start, but the clock recovery looks wrong (this can be seen zooming in or in the constellation plot). * QT GUI Time sink showing correlation does not triggers with the hardcoded value (200). I had to change it to 45. I'm having a hard time figuring out from the c++ code and documentation the right way to design the taps to put into Correlate and Sync and PFB Clock Sync blocks. I always find myself feeling I get contradictory clues from code, examples and documentation when choosing the taps for blocks that depend on PFB. Can you help me? Thanks!
test_corr_and_sync_for_square_waves.grc
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