That's no different than a straight analog receiver though, where LO
phase is generally not coherent with carrier or modulation phase. So
you use PLL or similar demodulators to recover carrier phase
Amiright?
--
Principal Investigator
Shirleys Bay Radio
Astronomy Consortium
http://www.sbrac.org
On Sep 1, 2010, at 9:19 PM, Tom Rondeau <trondeau1...@gmail.com> wrote:
On Wed, Sep 1, 2010 at 9:15 PM, Sam Keene <samke...@yahoo.com> wrote:
Ok, thanks, One more question... So does that mean we control the
NCO from the software?
I will have a look at those blocks.
thanks,
-Sam
No, the NCO is free running. We compensate for it in software.
Tom
--- On Wed, 9/1/10, Tom Rondeau <trondeau1...@gmail.com> wrote:
From: Tom Rondeau <trondeau1...@gmail.com>
Subject: Re: [Discuss-gnuradio] Newbie question on USRP2,
synchronization done by the FPGA?,
To: "Sam Keene" <samke...@yahoo.com>
Cc: discuss-gnuradio@gnu.org
Date: Wednesday, September 1, 2010, 9:03 PM
On Wed, Sep 1, 2010 at 8:52 PM, Sam Keene <samke...@yahoo.com> wrote:
Hi,
Thanks for the reply. I guess I am just trying to better understand
this diagram:
http://www.linuxjournal.com/files/linuxjournal.com/linuxjournal/articles/073/7319/7319f3.inline.jpg
I understand what the decimating filters are doing, but I'm a little
unclear about the NCO. Does this component phase and frequency lock
for me, or will I have to code that myself?
thanks,
-Sam
No, there is no freq/phase lock in the USRP/USRP2. We have to do
this in software.
You can reference the dbpsk and dqpsk blocks that we have already
written or the newer dbpsk2/dqpsk2 blocks that use newer techniques
for the phase, frequency, and timing locks.
Tom
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