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

[Douglas Geiger]

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Matt Ettus wrote:
> Changkyu Seol wrote:
>> Hi!
>>
>> I am planning to implement multiple synchronized transmitters using
>> USRP2 and GPS receiver. Before that I checked whether the USRP2 is
>> locked to external clock through following experiment.
> 
> 
> The easiest way to check for lock is to put the following line in your
> firmware:
> 
>     clocks_enable_test_clk(true,10);
> 
> This will output a test clock on the middle 2 pins of the 4 pin
> connector right near the VCXO on the motherboard.  Look at one of those
> 2 pins on an oscilloscope at the same time as the 10 MHz reference.  You
> should see the two clocks don't drift relative to each other.
> 
> Matt
> 
> 
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> Discuss-gnuradio mailing list
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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
source.
 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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