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Re: [Discuss-gnuradio] USRP2 modulated signal tx error

From: Eric Blossom
Subject: Re: [Discuss-gnuradio] USRP2 modulated signal tx error
Date: Wed, 25 Mar 2009 12:45:39 -0700
User-agent: Mutt/1.5.18 (2008-05-17)

On Wed, Mar 25, 2009 at 12:12:27PM -0700, Eric Blossom wrote:
> On Wed, Mar 25, 2009 at 12:09:36PM -0700, Johnathan Corgan wrote:
> > On Wed, Mar 25, 2009 at 11:30 AM, Eric Blossom <address@hidden> wrote:
> > 
> > > There's a bug in the on-the-wire format for the USRP2 where we're not
> > > currently transmitting the valid length of the packet.  With ethernet,
> > > the minimum packet size is 64-bytes, and there are some times where
> > > the host code is naively fragmenting the received samples in a way
> > > that produces a packet that is too short for ethernet.
> > >
> > > I've opened ticket:378 on this.  It will be properly fixed when we
> > > rework the on-the-wire format as part of the VRT work, but I think
> > > there's an intermediate step that can avoid most cases of the problem
> > > happening.
> > 
> > I had planned to at least temporarily work around this for gr-usrp by
> > avoiding passing flowgraph data to libusrp2 that would result in these
> > short fragments.  This wouldn't fix things for low-level libusrp2
> > users, but it's a small change that would get us by until the real fix
> > with the new VRT transport work.  Let me know if this is an issue.
> Johnathan,
> After a bit of lunch, I think I can fix this in libusrp2 in a few minutes.
> I'll set up a developer branch in a bit and you all know when it's
> ready to test.
> Eric


Can you please check out, build and install this developer branch and
let me know if your problem goes away?

  $ svn co http://gnuradio.org/svn/gnuradio/branches/developers/eb/t378


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