[time-nuts] Caveats on Allan Deviation with ultra stable oscillators

Magnus Danielson magnus at rubidium.dyndns.org
Fri May 30 19:47:23 EDT 2014


Hi Corby,

On 05/30/2014 07:26 PM, cdelect at juno.com wrote:
> Hi,
>
> I usually don't use drift removal as I want to see the effects of drift!

Yes, but the drift effect is not best represented in the ADEV, but phase 
or frequency plots however.

> The effects of oscillators locking together are very apparent on both the
> phase and AD plots when using a DMTD system. There was no indications of
> such locking!

Good to hear.

> My point was that if you are measuring ultrastable Quartz oscillators
> against each other the AD at the higher Tau will not reflect the true
> stability of the oscillators.
>
> Only a Maser or high performance Rubidium (HP5065A) will reveal the true
> behavior.

Would you care to give example plots to illustrate what difference you mean?

Cheers,
Magnus



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