[time-nuts] need recomendation for a portable 10mhz reference oscilator
SAIDJACK at aol.com
SAIDJACK at aol.com
Wed Dec 12 03:06:54 UTC 2007
In a message dated 12/11/2007 13:14:14 Pacific Standard Time,
bruce.griffiths at xtra.co.nz writes:
>Why not lock it to a GPS timing receiver output when its at home, and
>allow the controller to learn the aging and tempco characteristics etc
>of the oscillator being disciplined and use this information to correct
>for temperature variations etc at the remote site?
>The model used can be as complex as required to achieve the desired
>performance and a PC can be used to derive optimum correction
>coefficients, the micro only has to perform the simpler task of applying
>these corrections.
>Bruce
Hi Bruce,
the problem with that is that OCXO retrace can really suck.
Some common OCXO's have parts in E-09 and even worse retrace.
Doing about 10 minutes of Auto Survey on an M12+ receiver and OCXO warmup,
followed by about 20 minutes of active GPS locking will get you much better
performance than the OCXO retrace can achieve itself.
It would be interesting to see if OCXO retrace is very repeatable, if yes it
could be compensated for of course.
Or leave the power on at all times after calibration.
bye,
Said
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