[time-nuts] Why using HP5370 ext-ref is (maybe) a bad idea

Magnus Danielson magnus at rubidium.dyndns.org
Sat Mar 1 19:25:01 EST 2014

On 01/03/14 22:38, Poul-Henning Kamp wrote:
> In message <CAE3hgTd5UDz_-T5mvgBarYYyuLwn=+00p1Fho2Fs+T1p1xdGLQ at mail.gmail.com>
> , Brian Lloyd writes:
>> Instead of using the external reference input, any thoughts on actually
>> disciplining the internal OCXO to bypass the problem?
> The end result would be no different than using ext-ref.
> Right now I think the best approach to "smear" the error out, is
> to run ext-ref from a frequency which is well-known, but not
> synchronous with the input signals, for instance from a synth like
> the 3336 or a carefully mis-tuned GPSDO

Would work if integer cycles is covered over the measurement time such 
that samples is taken spread over the 100 ns reference cycle.

> The EFC pin on the OCXO in the 5370 is grounded in a way that makes it
> quite hard to unground.

Kapton tape into the connector, a wire soldered to EFC on the 10811?


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