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

[Feng Andrew Ge]

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


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
> 
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