[time-nuts] Interesting paper: Don't GPSD' your Rb...

Magnus Danielson magnus at rubidium.dyndns.org
Mon May 7 06:57:19 UTC 2012


Hi Bill,

On 05/07/2012 05:12 AM, Bill Hawkins wrote:
> Thanks for the analysis, Magnus.

Always happy to contribute.

> A few other time constants might be interesting -
>
> When a step change is made to the control voltage or current,
> how long does it take for the oscillator to settle down to a
> new value? Is it instantaneous compared to a second?

It depends on the rubidium FLL bandwidth. For OCXO it is much quicker.

> Do different components in different oscillators affect the
> settling time?

For rubidiums, yes. The FLL bandwidth will have such a "lag" effect 
until the slaved OXXO is back on track.

> It is not useful to make the next change before the last one
> is complete, at least for sampled systems. Using counters
> filters the change rather than taking a sample.

If you flip back and forth, then it makes sense because your phase 
deviations will be less.

You should however consider it when doing the stability analysis.

Cheers,
Magnus



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