Re: [Discuss-gnuradio] DQPSK bug or incorrect settings?

[Bob McGwier]

In a word, NEVER.  No self respecting communication systems designer 
would allow that much excess bandwidth on the air or any realistic 
transmission medium.

Typically 2-3 samples per baud is more than enough.  You then use a 
polyphase filter bank based clock recovery tool to FIND the correct 
upsampled phase (at SAY, 6-10 samples per baud) but you never operate 
the demodulator at that much oversampling.

I think Tom has finished and checked in the PFB based clock recovery 
based on the work by fred harris last summer-ish. Am I right?  If not, 
if I may be off assistance in finishing, I will.

Bob


On 8/8/2010 5:00 PM, Tom Rondeau wrote:
> On Sun, Aug 8, 2010 at 1:41 PM, Thunder87<address@hidden>  wrote:
> > Thunder87 wrote:
> > > If so, what is maximal and minimal safe "samples/symbol" to "samp_rate"
> > > rates?
> >
> > Minimal "samples/symbol" is 2.
> > Is there a maximal ?
>
> 215 is a pretty outrageous number to use; you should never need to
> oversample that much.
>
> 2 to 4 is typical, 6-10 is about the highest you probably want to go.
>
> Tom
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio


--
(Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio
Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,
NJQRP, QRP ARCI, QCWA, FRC.
“Be yourself, because the people who mind don't
 matter. And the people that matter don't mind."
-Dr. Seuss
Active: Facebook,Twitter,LinkedIn