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

Jerry Hancock jerry at hanler.com
Tue Jan 16 16:19:47 EST 2018


I am working to build a small DMTD system based on Bill Riley’s paper.   Bill was kind enough to send me a package with updates.  In the meantime, I tested an AD8302 phase detector coupled to an HP voltmeter (HP3456 and HP3457), both with the filter set.  I believe the HP3456A voltmeter filter limits voltage changes to below 60hz.  The results were interesting but I don’t have anything to compare them with though they did look correct from a relative standpoint.  For instance, my Cs beam looked better than one Rb unit and my GPSDOs looked better at longer Tau.  My HP 10811 looked correct when compared to others.

The issue with the AD8302 though is that phase deltas below 3 degrees are inaccurate, actually the plots had flats at those phase deltas.  Also, since it reports in degrees, you need to change that back to time which I did in a spreadsheet.  

Regards,

Jerry


Jerry Hancock
jerry at hanler.com
(415) 215-3779

> On Jan 16, 2018, at 8:58 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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