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Re: [Discuss-gnuradio] QAM, carrier tracking and clock recovery
From: |
Martin Dvh |
Subject: |
Re: [Discuss-gnuradio] QAM, carrier tracking and clock recovery |
Date: |
Thu, 01 Feb 2007 23:02:54 +0100 |
User-agent: |
Debian Thunderbird 1.0.2 (X11/20061113) |
Tom Rondeau wrote:
>>-----Original Message-----
>>From: address@hidden [mailto:discuss-
>>address@hidden On Behalf Of Martin Dvh
>>Sent: Wednesday, January 31, 2007 10:24 PM
>>To: gnuradio mailing list
>>Subject: Re: [Discuss-gnuradio] QAM, carrier tracking and clock recovery
>>
>>You might find my benchmark_rx_oscopy.py and kinda working qam16 code
>>interesting.
>>they are in branches/developers/nldudok1/digital-wip3 which is a branched
>>version of your digital-wip2
>>look in
>>branches/developers/nldudok1/digital-wip3/gnuradio-
>>examples/python/digital/
>>and
>>branches/developers/nldudok1/digital-wip3/gnuradio-
>>core/src/lib/general/gr_mpsk_receiver_cc
>>and
>>branches/developers/nldudok1/digital-wip3/gnuradio-
>>core/src/python/blksimpl
>>
>>benchmark_rx_oscopy.py gives you a live constellation view (put it at X-Y
>>mode manually with the rightmost pulldown)
>>and live tweaking of parameters
>>
>>greetings,
>>Martin
>
>
>
> I just saw the commit now. I'll check it out tomorrow and see what it looks
> like. You guys are my new heroes; I wouldn't have been able to touch this
> for a while yet ;)
>
> How's it working with the AGC loop?
The agc2 seems to work.
The feedforward agc only works when manually compensating for the noise (1.0 +
noise as reference)
This would need an error loopback from the gr_mspk receiver
I think my main problem now is detecting of which quadrant we are in.
Or use the right kind of differential coding.
(I just used the gr.diff_decoder_bb and gr.diff_encoder_bb)
I have also strugled with the right formulation for the phase_detector error
signal.
(conj or not, pos or neg sign) But I think I got it now.
I send the complete constellation as list from python to the mpsk_receiver as
vector.
For some reason I had to reverse this list to get it to work.
This could also mean I needed to solve this in a different way and it just
accidently now sometimes works. (mirror the constellation, add pi,
something like that)
Greetings,
Martin
> Tom
>
>
>
>
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- Re: [Discuss-gnuradio] QAM, carrier tracking and clock recovery,
Martin Dvh <=