[time-nuts] Setting Rubidium to match GPS source

[Bruce Griffiths]

Pete wrote:
> Chris,
>
> The 3575A does NOT have adequate phase resolution to set an Rb
> source to match a GPSDO. A few, now rather old, phase meters were
> sold for this purpose, but they used a strip chart recorder to average
> phase shift over 1 to 24 hour measurement times & required great
> investments of time to use.
>
> I proposed a 1KHz heterodyne scheme for this very purpose on this
> list a few months ago. The scheme took a few hits for lack of state-
> of-the-art performance, but I'm still using it without suffering any
> disappointments. It does require you to have a few items of test
> equipment (readily available on eBay) which not everyone has &
> it requires some circuit construction using readily available parts.
> Except you must wind a couple of 5mH inductors on your own.
>
> Contact me off-list if you want more details.
>
> Regards,
> Pete Rawson
>
> _______________________________________________
>   
Pete

Despite your claims the hits werent just for lack of state of the art
performance.
This circuit is an example of poor design practice and a lack of
understanding of some of the fundamentals of electronic design.
Just throwing something together without a good understanding of its
operation and its limitations is never a recipe for reliable operation.

You can also do much better with well designed circuit preferably with a
lower beat frequency.

It is also relatively easy to build a phase meter circuit with a
resolution of around 1E-11/T or better using a few flipflops and a sigma
delta ADC instead of a chart recorder.

Bruce