[Discuss-gnuradio] An automated PSK125 decoder

[Matthias Brändli]

Hello all,

my local amateur radio repeater[1] transmits a PSK125[2] beacon once a
day with some statistics, and I used GNURadio to build an automated
decoder. A cronjob runs rtl_sdr to capture IQ to a file, runs the
gnuradio flowgraph, and a python file decodes the varicode to get the
text message.[3]

I'm sending this email because the digital_mpsk_receiver_cc is
deprecated. I tried using the Polyphase Clock Sync as described in
https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation but
could not get it to work due to an error about the block requesting too
many samples. Probably a mistake in the parameter settings...

The tutorial says "This tutorial, however, should in no way be meant to
suggest that this is the only way to accomplish this task." What would
you consider to be the cleanest approach to demodulate a PSK signal?
Using constellation_receiver_cb?

Cheers and hope to hear you on the repeater :-)

Matthias
  HB9EGM

[1]
HB9G on 145.725MHz, NBFM modulation: http://www.glutte.ch/

[2]
PSK125 is identical to PSK31 except for the number of samples per
symbol. See http://aintel.bi.ehu.es/psk31.html

[3]
https://github.com/Glutte/glutt-o-matique/tree/master/decoder

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