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Re: [Discuss-gnuradio] Why does increased Samples per Symbol result in u
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] Why does increased Samples per Symbol result in underruns? |
Date: |
Mon, 20 Jul 2009 21:36:46 -0700 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Mon, Jul 20, 2009 at 09:10:07PM -0500, Mir M. Ali wrote:
> Does that mean that the data being sent is lost or is it just that USRP is
> waiting for it to arrive?
uU means that there's a discontinuity in the transmitted burst. The
USRP needed to transmit some data, but there was none to send. The
receiver will not be able to demodulate the malformed burst.
> On Mon, Jul 20, 2009 at 6:30 PM, Eric Blossom <address@hidden> wrote:
>
> > On Mon, Jul 20, 2009 at 05:29:02PM -0500, Mir M. Ali wrote:
> > > Hi,
> > > I used benchmark_tx.py with dbpsk modulation with Samples per symbol=7
> > and
> > > higher. I found that this resulted in lots of USRP underruns(uU). Why is
> > it
> > > so?
> >
> > You're doing more work per symbol. The uU indicates that the host is
> > not sending data to the USRP fast enough.
> >
> > Eric