Hello:

I'm now working on a precision clock where hopfully the initial frequency offset, temperature effects and aging will be corrected.  I'm using a 20 MHz (or 10 MHz) unit oscillator because it saves a pin on the
12F675.  Some typical data are:
26 deg C    19,999,740 Hz
55 deg C    19,999,600 Hz
70 deg C    19,999,650 Hz

Have Fun,

Brooke Clarke, N6GCE
http://www.precisionclock.com


> How large drift can I expect to be caused by temperature changes? I left
> my clock running last night and it was ahead 1 second after 3 hours and
> then stayed behind 4 seconds during next 6 hours. If the room
> temperature day/night change caused such a drift, what can you expect
> from extreme conditions in a rally car where temperature can change from
> -20C in the winter to +60C under the sun in the summer!? I'm starting to
> believe that using some kind of temperature controlled osc is a must in
> my case...
>
> Tauno

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