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Re: [Discuss-gnuradio] DPSK demod parameters question
From: |
Martin Braun (CEL) |
Subject: |
Re: [Discuss-gnuradio] DPSK demod parameters question |
Date: |
Wed, 11 Jul 2012 10:07:09 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, Jul 10, 2012 at 11:40:00AM -0500, Javier M. Suarez wrote:
> I am working with DPSK mod and demod blocks. I would like to know if anyone
> knows what is the meaning of the parameters in DPSK demod. I've looked for
> them
> but I havent found anything.
Hi Javier,
assuming you know how a PSK receiver works:
> The parameters are:
> FLL Bandwidth
> Phase Loop Bandwith
> Timing bandwith
> Omega relative limit
This block does *everything* from complex samples to bits.
The 3 bandwidths set the parameters for frequency, clock and phase
recovery (Tom explained the bw parameter quite well here:
http://gnuradio.squarespace.com/blog/2011/8/13/control-loop-gain-values.html)
What is confusing is the 'omega' parameter, I must admit, because it's
not actually connected (it doesn't do anything). Now if you think about
a PSK Rx for a second, you /might/ expect an AGC, and I'm guessing
that's where that parameter went. But as I said, ignore that.
About finding that stuff: the FLL is actually documented quite well
(check e.g.
http://gnuradio.org/doc/doxygen/classdigital__fll__band__edge__cc.html,
which is the 3rd result for a 'gnuradio fll' google search on my end),
but it's not filed under 'synchronization', so perhaps that's where you
went wrong.
MB
--
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)
Dipl.-Ing. Martin Braun
Research Associate
Kaiserstraße 12
Building 05.01
76131 Karlsruhe
Phone: +49 721 608-43790
Fax: +49 721 608-46071
www.cel.kit.edu
KIT -- University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association
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