[time-nuts] 10MHz Rubidium reference source for frequency counter

Charles Steinmetz csteinmetz at yandex.com
Fri Oct 31 16:27:45 EDT 2014


Karen wrote:

>The next OCXOs have been tested today:

Did you test the oscillators free-running (NOT in your GPSDO)?  If 
so, those plots look much too high (by at least an order of 
magnitude, maybe even 2 or more OOM for some of the oscillators).

Of course, oscillators take time to settle to their best stability -- 
as much as several weeks or even several months for some -- so if you 
just turned them on and measured them a few hours later you can 
expect higher than normal ADEV results.  Even so, these results seem high.

But if you measured them in your GPSDO circuit, you have not 
separated the potential measurement problems from potential GPSDO problems.

If you suspect the time base in the Pendulum, you can use one of the 
OCXOs to feed its external reference input.

Best regards,

Charles





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