[time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit

[Dr Bruce Griffiths]

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