Re: [Discuss-gnuradio] Run USRP at alternate clock frequency?

[Clark Pope]

I'll try the heat gun solution first. (Gives me an excuse to buy one.)

Regarding the rational resampler: that is in software, right? I'm trying to 
run at 44 MHz so I can do the despreading for 802.11 inside the FPGA. I 
think I can do the differential detection in the fpga too so that the stream 
to the PC will just be the raw bits.

I've done some matlab simulations with good results using the USRP to 
collect off my own wlan. Even without an equalizer I'm getting near perfect 
packet reception.

Technically, if the packet rate is low enough I could do everything in 
software IF I put some smarts in the FPGA to only send the IF samples that 
belong to a packet. But net traffic would have to be less than a couple 
percent to be sustainable.

-Clark

> From: Matt Ettus <address@hidden>
> To: discuss gnuradio <address@hidden>,  Clark Pope 
> <address@hidden>
> Subject: Re: [Discuss-gnuradio] Run USRP at alternate clock frequency?
> Date: Fri, 31 Mar 2006 16:02:35 -0800
>
>
> Clark Pope wrote:
> >
> > I finally got my 44MHz oscillator in. Tried to remove the existing
> > oscillator but I got nowhere with my iron and copper braid. Can anyone
> > suggest a cheap tool that will allow me to get this surface mount
> > oscillator up?
>
> Nope.  Its tough unless you have a Metcal talon.  I would suggest that
> you just cut the traces from the 2 pins on the left side and the one on
> the right.  This will disable the oscillator, but would be very hard to
> undo.
>
> If there were a warranty, this would definitely void it :)
>
> The USRP Rev 4's which are shipping now are much easier to run off an
> external oscillator, but that won't help you.
>
> By the way, we also have very good and fast rational resamplers in the
> source.  Are you sure that wouldn't help you?
>
> Matt

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