[Discuss-gnuradio] Why no phase ambiguity in digital-bert...

[Jason Uher]

> I notice in the digital-bert example (benchmark_rx.py and
> receive_path.py), the Costas loop actually occurs prior to the MM
> sampler, without being wrapped inside the mpsk_receiver: (lines 104-105
> of
> http://gnuradio.org/cgit/gnuradio.git/tree/gnuradio-examples/python/digi
> tal-bert/receive_path.py)
>
> self.connect(self, self._agc, self._rrc, self._costas, self._mm,
>                     self._c2r, self._slicer, self._descrambler,
> self._ber)
>
> Are these operations generally interchangeable?
>
> Thanks
>
> Ian.

My explanation pertained  to the benchmark_rx; but Johnathan  already
said it doesnt  matter in his first reply ;)

>Not sure what post you are referring to.  While a Costas loop can
>indeed operate on a single sample per symbol, it can also operate on
>more than that.  Different strategies in a receiver chain places the
>frequency/phase synchronization at different places.