[time-nuts] GPS: ADEV or MDEV?
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Mon Apr 23 21:53:27 EDT 2007
SAIDJACK at aol.com wrote:
> Hi Tom,
> BTW: the retrace hysterisis of typical very high-quality OCXO's is speced at
> 1E-08 (24 hours off, 2 hours on) that's probably a lot worse than the voltage
> reference zener retrace will be.
> A typical 20ppm Hysterisis on a 5V Zener with the OCXO having a +-22Hz
> (0-5V) adjustment range gives 4.4E-011 retrace. Several orders of magnitude better
> than these particular OCXO's inherent retrace by itself.
If an unheated reference exposed to wide ambient temperature swings is
used then hysteresis may be significant when the OCXO is continuously
The significance and magnitude of the effect depends on the range of
ambient temperature variations experienced.
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