[time-nuts] Comparing the frequency of two gpsdo's.

Magnus Danielson magnus at rubidium.dyndns.org
Sat Nov 13 11:33:36 EST 2010

On 11/13/2010 05:18 PM, Mark Spencer wrote:
> Hello:
> I'm looking for some advice about ways I can compare the frequency of two gpsdo's.  To date I have been using an oscilloscope that supports phase measurements to measure the small (typically 10 degreees or so at 10 mhz) change in phase between the two signals over a period of a few hours and then calculating the frequency change.
> I realize this is sub optimal but I wanted to use the gear on hand.   Recently the phase measurement fuction of my scope has stopped working.
> As the useage I have ever found for the phase measurement function in my scope was comparing the frequencies between gpsdo's I'm thinking it might be better to invest in some other equipment rather then getting the scope fixed.
> Any thoughts as to what could be obtained used for less than 1K that would be suited for this type of measurement ?

Have a look at the PICTIC II. If you feel like going further down the 
steep end, the DMTD kit would be a solution. Both assumes you are 
willing to do some soldering and source components yourself.

As for my own sake, the DMTD PCB kit sits here and I need to source the 
remaining components. Something to do a dark November weekend. Hm. I'll 
have a go at it.


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