Re: [Discuss-gnuradio] USRP2 and external clock (from GPS receiver)

[Douglas Geiger]

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Matt Ettus wrote:
> Douglas Geiger wrote:
>>
>> Is the test clock supposed to be running at 5kHz? I've just tested this
>> on one of my USRP2 - it does appear to be locked with my external clock
>> - - i.e. the 5kHz signal on the pin doesn't drift w.r.t my 10Mhz external
> 
> 
> No, the test clock runs as 100MHz/div where div is the 2nd argument to
> the function.  The maximum value of div is 32.
> 
> I think you are using a digital oscilloscope to view this, and you are
> seeing it alias because you turned the time per division up way too
> high.  Change it to 100ns per division.
> 
> Matt

 Ah - that's was the problem. Unfortunately my scope can only handle a
single channel at 100MHz, so setting the divisor >2 helps.
 Unfortunately it appears the clock is not synchronized with my external
10MHz clock - any suggestions on further steps to debug why I'm having
trouble?
 Thanks,
  Doug

- --
Doug Geiger
Research Assistant
Communications and Signal Processing Lab
Oklahoma State University
http://cspl.okstate.edu
address@hidden
address@hidden
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