[Discuss-gnuradio] How to implement 64QAM?

[alanluo]

Hi, everyone:

recently I have a project which need to use higher modulation scheme, such
as 16QAM or 64 QAM. I noticed that in python/gnuradio/blksimpl, there is no
demodualtion part for higher modulation schemes. Is that means we need to
finish it by ourself?
And i also noticed that from the maillist attached as below, Tom seems
working on the modualtion models. Did he finish this work, and post at some
place i just did not find ?

I really appreciate any help from you guys. Since I am very new to the
python language and dont have confidence to programme the model in such
short time.

====
RE: constellation mapping  

by trondeau Mar 06, 2007; 05:44am :: Rate this Message:    - Use ratings to
moderate (?) 

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> -----Original Message----- 
> From: address@hidden [mailto:discuss- 
> 
> On Sun, Mar 04, 2007 at 06:20:07PM -0500, address@hidden wrote: 
> 
> > I want to do constellation mapping in pyhton.  I have code that does 
> > a gr.packed_to_unpacked_bb and then gr.chunks_to_symbols_bc using a 
> > constellation of: 
> > 
> > constellation=array((1+1j,1-1j,-1-1j,-1+1j),Complex) 
> 
> Use this: 
> 
>   constellation=(1+1j,1-1j,-1-1j,-1+1j) 
> 
> > My understanding is that this is the constellation mapping for QPSK. 
> > I want to do constellation mapping for BPSK and 64-QAM.  I don't 
> > have a lot of GNU radio experience so I'm not really sure how to do 
> > this.  Is all I do is change the array (all the possibilities from 
> > 4+4j to -4-4j for 64-QAM and 1+0j to -1+0j for BPSK) and the code 
> > will do the rest to map the data for the other modulation schemes? 
> 
> Have you looked at the mpsk code that's in the tree?  Most of this 
> stuff is already in place.  I believe that Tom Rondeau is working on 
> QAM too. 
... [show rest of quote]

Yep, you can already look in python/gnuradio/blksimpl for DBPSK and DQPSK. 
I'm finishing up the tests on the new stuff now and hopefully will get those 
checked in to the trunk by the end of today. 

This will include D8PSK and a number of square QAM modulations up to M=256. 
These are currently disabled until the receivers are finished, but the code 
will be there to see how I'm doing it. The modulators have been verified 
using our signal analyzer. 

Tom
====


Best wishes,

Alan
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