Re: [Discuss-gnuradio] On air 16_QAM transmission problem with USRP N210

[Tom Rondeau]

On Wed, Apr 30, 2014 at 10:58 AM, zielalaoui <address@hidden> wrote:

Hi all,
For synchronization I did not add blocks because the QAM.py calls
synchronization blocks from generic_mod file which already contains AGC,
fll, polyphase clock synk, ... I thought that those bolcks are doing the
job. So i just think to add FEC block because it is not a part of my
flow-graph. Do you thinks that i should add synchronization block even it
exists in QAM demod block? or just try to find the best parameters of
timing, frequency, and phase in de QAM_demo block?
Thanks a lot for help.

Yes, synchronization for QAM is difficult and not extremely well-tested in GNU Radio. Have you done this in simulation, yet? That is, make a GRC example with the transmitter and receiver and the add a channel model block to see what happens? Definitely start there before getting ahead of yourself and adding the complexities of the real world.

Tom