The feedforward AGC system in DttSP is more complex in that it is two
track (fast and "user set"). I believe I already mentioned this so I
won't go over it again. But let me reiterate one important feature of
our work. One of the things that was important to its success as a
feedforward agc was to respond to a level change 3 times constants early
in a simple predictive system. The 3 time constants varied depending
on the changing speed of the agc as set by the user.
Bob
'Eric Blossom' wrote:
On Mon, Sep 25, 2006 at 11:35:33PM -0400, Tom Rondeau wrote:
Eric,
Here's a brief write-up on the tests I ran for the AGC loops. It looks like
the feedforward has a slight advantage over most of the test cases.
I thought I'd email this to the listserv in case anyone is interested in the
digital modulations. Basically, we're working on getting stable DBPSK and
DQPSK modulators into the code base. The AGC loops seems to be producing
problems, much of which is caused by driving the Costas loop crazy at the
next stage of the receiver. Future work will include creating a non-coherent
receiver for the differential modulations to take out the Costas loop.
Tom
Hi Tom, thanks for making the measurements and writing them up.
I'll be merging the results of all this work into the trunk tomorrow.
Thanks to Tom for all the effort he's put into sorting out the DBPSK
and DQPSK. And thanks to Matt for suggesting the feed forward AGC.
Eric
--
Robert W. McGwier, Ph.D.
Center for Communications Research
805 Bunn Drive
Princeton, NJ 08540
(609)-924-4600
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