Hello folks,
I am trying to resolve the 90* ambiguity of costas for a QPSK receiver, and was
hoping folks could weigh-in in case anyone had success with this in the past.
yes, diff encoding works.. :) trying to make it work without though.
Also, I had seen Tom R's example of his cor-and-sync
quick update - thinking about it a bit more thoroughly, the up-sampling
approach I considered below won't likely correlate as well as picking a
preamble such that its real portion is the same in both bpsk and qpsk.
From: Landsman, Arik
Sent: Saturday, Mar
On Sun, 2016-03-13 at 01:35 -0500, discuss-gnuradio-requ...@gnu.org
wrote:
> Message: 1
> Date: Sat, 12 Mar 2016 21:34:03 +
> From: "Landsman, Arik"
>
> Hello folks,
>
> I am trying to resolve the 90* ambiguity of costas for a QPSK
> receiver, and was hoping folks could weigh-in in case an
ation%20systems&Ntx=mode%20matchallpartial
From: Andy Walls [a...@silverblocksystems.net]
Sent: Sunday, March 13, 2016 8:51 AM
To: discuss-gnuradio@gnu.org
Cc: Landsman, Arik
Subject: Re: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
in qpsk
On Sun, 20
: Monday, March 14, 2016 11:59 AM
To: Andy Walls; discuss-gnuradio@gnu.org
Subject: RE: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
in qpsk
Hi Andy,
Thank you for the detailed answer, I am certainly going to try what you suggest
in the next couple of days. will post with upda
lates the input,
I'd would probably be easier for me to see what's wrong about the
corr_est process.
Regards,
Andy
> Many Thanks,
> Arik
>
>
>
>
>
>
>
>
>
> From: Landsman, Arik
> Sent: Monday, March 14, 2016 11:59 AM
> To: Andy Walls;
ut are labeled
properly. Hopefully easy to follow.
And thanks again!
Arik
From: Andy Walls [a...@silverblocksystems.net]
Sent: Friday, March 25, 2016 6:45 PM
To: Landsman, Arik
Cc: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] costas ambiguity a
Arik
>
>
> ________
> From: Andy Walls [a...@silverblocksystems.net]
> Sent: Friday, March 25, 2016 6:45 PM
> To: Landsman, Arik
> Cc: discuss-gnuradio@gnu.org
> Subject: Re: [Discuss-gnuradio] costas ambiguity and correlate-and-sync blo
ot the weekend is my sweet
spot..
Thanks,
Arik
From: Andy Walls [a...@silverblocksystems.net]
Sent: Wednesday, March 30, 2016 4:56 PM
To: Landsman, Arik
Cc: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] costas ambiguity and correlate-and-syn
the symbols in an
> > > unpredictable way - nothing seems to be off.
> > >
> > > As the ultimate check I usually loop the input file ("packet" if you
> > > will) and compare it at the Rx. "Hello World" pops here and there but not
> > &
This is OK as long as you are very close to the correct
center frequency. The measured phase rotation will become less correct the
farther you move from the measurement point at the peak of the correlation,
if you don't have good frequency lock when performing the correlation.
Regards,
Andy
&
tag marking delay to 0, to mark the first symbol in the preamble
> with the phase correction. This is OK as long as you are very close to the
> correct center frequency. The measured phase rotation will become less
> correct the farther you move from the measurement point at the peak of the
ls [a...@silverblocksystems.net]
Sent: Saturday, April 02, 2016 8:11 PM
To: Landsman, Arik
Cc: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
in qpsk
Hi Arik:
On Sat, Apr 2, 2016 at 7:41 PM, Landsman, Arik
>
wrote:
Hi Andy,
Still loo
hase offset, the Rayleigh fading,
fast varying CFO, and fast varying Phase Offset will be the worst.
Regards,
Andy
> Thanks,
> Arik
>
>
> ______
> From: Andy Walls [a...@silverblocksystems.net]
> Sent: Saturday,
On Sun, 2016-04-03 at 19:33 -0400, Andy Walls wrote:
> On Sun, 2016-04-03 at 20:24 +, Landsman, Arik wrote:
>
> > btw, played with tag delay manually, this has an immense effect on
> > costas rotation once fading model is added to channel.
>
> Well there are a number of things going on here,
uot;
-Andy
From: Andy Walls [a...@silverblocksystems.net]
Sent: Sunday, April 03, 2016 7:33 PM
To: Landsman, Arik
Cc: discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
in qpsk
On Sun, 2016-04-03 at 20
On Tue, 2016-04-05 at 00:00 +, Landsman, Arik wrote:
> Hi Andy,
>
> Added a few comments inline (marked with "==" in lieu of a better email
> client)..
>
> But overall corr_est works very consistently. I did have a few observations:
Hi Arik:
For my responses to the next two, I'm assuming
andsman, Arik
Cc: discuss-gnuradio@gnu.org; t...@trondeau.com
Subject: Re: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
in qpsk
On Tue, 2016-04-05 at 00:00 +, Landsman, Arik wrote:
> Hi Andy,
>
> Added a few comments inline (marked with "==" in lieu of
Cc: discuss-gnuradio@gnu.org; t...@trondeau.com
Subject: RE: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
in qpsk
Hi Andy,
Sorry for delayed response, the weekend finally arrived.. added some comments
inline below. Your comments on zero-IF receiving are well taken - go
python it into the Rx in a neat way.
From: Landsman, Arik
Sent: Sunday, April 17, 2016 7:44 PM
To: Andy Walls
Cc: discuss-gnuradio@gnu.org; t...@trondeau.com
Subject: RE: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
in qpsk
Hi Andy
PM
> To: Andy Walls
> Cc: discuss-gnuradio@gnu.org; t...@trondeau.com
> Subject: RE: [Discuss-gnuradio] costas ambiguity and correlate-and-sync block
> in qpsk
>
> Hi Andy,
>
> Just a quick update - I changed sps from 10 to 5 to repeat your trimming
> procedure. Wor
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