Re: [Discuss-gnuradio] 25 MHz of instantaneous RF bandwidth on USRP2

[Eric Blossom]

On Sun, Sep 14, 2008 at 09:07:07PM -0400, Feng Andrew Ge wrote:
> Eric,
> 
> I am just wondering whether this piece of code exists somewhere or not
> to enable 
> 
> > 
> > 100MS/s I & Q is decimated to 25MS/s complex.  We use 16-bit I & Q.
> > That works out to ~800Mbit/s on the gigabit ethernet,  which the USRP2
> > can sustain, no problem.  
> 
> If so, would you please kindly point out?
> 
> Thanks,
> Andrew

This is for the USRP2 not the USRP1, and yes it does exist.

The USRP2 code is not yet stable, and the API's are still subject to
change, but you can find it by looking in the usrp2 directory in the
gnuradio trunk.   See also gr-usrp2 for the GNU Radio glue.

Again, none of this is stable.  YMMV, etc, etc.

Eric

> On Fri, 2008-09-12 at 16:37 -0400, address@hidden
> wrote:
> > On Fri, Sep 12, 2008 at 01:54:08PM -0500, Douglas Geiger wrote:
> > > Very exciting!
> > >
> > > One technical question:
> > > By 25 MHz of instantaneous RF bandwidth - do you mean the
> > 100Msamples/s 
> > > from the ADC gets decimated down to 50Msamples/s?  In which case, is
> > the 
> > > Gig-E able to handle that much sustained throughput (I'm guessing
> > that's 
> > > with 8-bit samples?).
> > 
> > 100MS/s I & Q is decimated to 25MS/s complex.  We use 16-bit I & Q.
> > That works out to ~800Mbit/s on the gigabit ethernet,  which the USRP2
> > can sustain, no problem.  
> > 
> > > Also, does the locking of the clocks of multiple USRP2's work like
> > the 
> > > USRP, e.g. where I can set one as the master and the other as slave
> > - i.e. 
> > > is the MIMO cable you refer to a coax SMA-SMA cable to connect the
> > clock 
> > > in/out connect (which have to be soldered in place) and the 2-wire
> > cable to 
> > > the daughterboard (like described on 
> > > http://gnuradio.org/trac/wiki/MultiUsrp)?
> > 
> > No soldering required.  The mimo cable is a serial attached scsi cable
> > repurposed for our needs.  The host configures the clocking on the
> > USRP2s over the ethernet.
> > 
> > Here are the clocking options:
> > 
> >   USRP uses it's own free running xtal oscillator
> >   USRP uses the external reference input (SMA connector)
> >   USRP uses the clock provided over the MIMO cable.
> > 
> > In addition, the master is programmed to drive clock onto the 
> > MIMO cable.
> > 
> > Eric