[time-nuts] Measuring ADEV with a PM6681 or CNT-81

[Magnus Danielson]

Hal Murray wrote:
>> The PM6681 does not appear to have support for measuring time
>> intervals in positive and negative directions at the same time. That
>> would limit the usefulness of this trick, it seems. Or is it just as
>> valid to use the opposite edge of one of the signals? 
> 
> Will a long chunk of coax shift one signal far enough so you can be sure of 
> the order?

No. Consider a low frequency difference, and you will slowly shift 
through all phase relationships. You need to handle them all without 
dropping a measurement.

Cheers,
Magnus