Re: [Discuss-gnuradio] constellation object

[Tom Rondeau]

On Sat, Jan 15, 2011 at 1:40 AM, Ben Reynwar <address@hidden> wrote:
> Hi all,
>
> What do people think of introducing a constellation object into gnuradio?
>
> It would hold the constellation points and also a decision-making function.
> New modulations could then be easily created by subclassing a constellation.
>
> It would also mean that the decision-making function for a given
> modulation could
> easily be used by different receivers (i.e. the standard receiver and
> the ofdm receiver would
> both use the same decision making code for a given modulation).
>
> I've already had a go at implementing this on my repo.
>
> https://github.com/benreynwar/gnuradio/blob/master/gnuradio-core/src/lib/general/gr_constellation.h
> https://github.com/benreynwar/gnuradio/blob/master/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h
> https://github.com/benreynwar/gnuradio/blob/master/gnuradio-core/src/python/gnuradio/blks2impl/qam.py
> https://github.com/benreynwar/gnuradio/blob/master/gnuradio-core/src/python/gnuradio/blks2impl/generic_mod_demod.py
>
> Cheers,
> Ben


Ben,
Are you talking about something different than
gr_constellation_decoder_cb? I haven't looked at your code, but it
strikes me that what you want is similar to that decoder code (you can
find its use in dbpsk.py and dbpsk2.py in
gnuradio-core/src/python/gnuradio/blks2impl).

My only suggestion for this part is to have a constellation_decoder_cf
that would output soft symbols instead of hard symbols.

Let me know if I've missed something in what you are asking.

Thanks,
Tom