[time-nuts] Time interval measurement vs dual mixer method

Bob kb8tq kb8tq at n1k.org
Tue Jan 16 15:46:05 EST 2018


Hi

You have to measure two different outputs to do what you describe. The PPS measurements 
are limited to > 1 x10^-10 with most counters at tau = 1 second and 2x10^-11 with some exotic
models. The mixer based stuff can get around three orders of magnitude past that at the same
tau. Since a practical mixer system involves filtering one would expect some impact from that. 
The gotcha is the low resolution of the counter approach. You run out of resolution before you
can really see anything. 

All that said, yes, I have measured the same device both ways and the results do agree 
within the accuracy constraints imposed by the techniques. 

Bob

> On Jan 16, 2018, at 11:58 AM, slawek dabrowski <slawdabr at wp.pl> wrote:
> 
> 
> Hello to the group!
> 
> Have you ever measured frequency standard (or other precision oscillator) simultanously by time interval method (difference between 1 pps ref and 1 pps DUT) and dual mixer method (e.q. with phase/frequency comparator)? I'm very interested in results.
> 
> Slawek
> 
> 
> 
> 
> 
> 
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