[time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sat Dec 16 22:44:39 UTC 2006
Hal Murray wrote:
>> You still want to produce some form of quality measure for the ADEV
>> shape in order to form some form of control loop.
>>
>
> Suppose I build I good GPSDO. How do I determine how good it is? (or even
> if it is any good)
>
> How much do I learn by just plotting the control voltage?
> How much do I learn by comparing it with a good non-disciplined crystal?
>
>
> Do I have to get a cesium clock so I have a better reference? But then how
> do I tell how good my cesium clock really is?
>
>
>
>
Hal
One oscillator is never enough you need at least 3, preferably more.
Then if they are statistically independent with not too dissimilar
instabilities then one can get some idea of the instability of each
oscillator.
Using several different technologies (crystal oscillators, Caesium
standards, hydrogen masers etc) also helps increase confidence in the
results.
Bruce
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