[time-nuts] Question on disciplining oscillators
SAIDJACK at aol.com
SAIDJACK at aol.com
Tue May 2 22:40:28 UTC 2006
Hello Javier,
this depends on your Rb oscillator, and if you use an external DAC circuitry
then the DAC and DAC reference thermal sensitivity as well.
Typically, the Rb including the DAC and DAC reference will be better than
the GPS for time frames from 1000 to 10000s. The GPS will probably be better
than the Rb above 10000s and should thus be allowed to correct the Rb at such
longer intervalls.
So try starting with a cut off frequency of around 3000s, then try 10K or
even 20K intervalls for really good Rb's. Keep in mind that your DAC and DAC
reference likely have 2-5ppm temperature coefficient themselves, and may thus
affect your Rb accuracy.
Simple OCXO's seem to work well with a time constant of around 1000s or less
since they are much worse than the GPS at those times and benefit from the
GPS corrections above 1000s measurement intervalls.
bye,
SJ
More information about the Time-nuts_lists.febo.com
mailing list