Re: [Discuss-gnuradio] USRP2 backward compatibility questions

[Chris Stankevitz]

Chris Stankevitz wrote:
> 5. My application requires the USRP to use the external clock provided
> by my front end.  It runs at 64 MHz.  Will the USRP2 accept this 64 MHz
> clock?  (I'm guessing not since it appears the USRP2 runs at a different
> frequency).  I can provide a sine or square wave clock.

Yes.  From the FAQ (http://www.gnuradio.org/trac/wiki/USRP2GenFAQ):

Does the external frequency reference have to be 10 MHz? Can I use 100 MHz?

Actually, you can use 100 MHz as well, you will just need to change one
line of the firmware to set the R-divider on the PLL. You can use any
frequency for which the following equation has a solution:

   100 MHz / N = Ref / R
       for which N and R are integers and smaller than 32,768