Re: [Discuss-gnuradio] gr-digital / gmsk_demod M&M vs PFB

[Tom Rondeau]

On Sat, Aug 31, 2013 at 1:09 PM, Ryan Pape <address@hidden> wrote:
> In looking at gmsk_demod currently, it is using M&M clock recovery, but
> here:
>
> http://gnuradio.org/redmine/projects/gnuradio/repository/revisions/2f75b230e1a54ce10900ad37520dd03ff01685e8/entry/gr-digital/python/gmsk.py
>
> in 2011 it was  switched to use PFB clock sync before things were
> reorganized.
>
> Was the switch back to M&M intentional?

It was switched back intentionally. Since GMSK uses a Gaussian filter
instead of an RRC, the PFB recovery loop was acting very odd and
distorting the signal. At the time, I was too busy with other projects
to figure out why, so I just went back to the known-working M&M loop.
The PFB recovery block should work for this modulation, though, so it
would be good if someone wants to work on it, I would really
appreciate it.

-- 
Tom
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