[time-nuts] getting a grip on 10811 drift (beginner-ish question)
Charles P. Steinmetz
charles_steinmetz at lavabit.com
Fri Nov 9 23:43:27 UTC 2012
Chris wrote:
>My perpetually drifting 10811 pretty quickly made it to the negative
>voltage rail on the control voltage.
Is this an oscillator you just powered up after it had been off for a
long time? The most common versions of the 0811 are specified for
drift of less than 5 x 10e-10 per day after they have been on for a
month. IME, they usually meet that spec within a week of being
turned on, even if they have been off for a long time. Mine run from
about 2 e-11 to 2 e-10 per day (note that they are on continuously).
>I put in a 1/4 watt 50 ohm resistor (like the parts list called
>for). My working hypothesis is that the small resistor was changing
>impedance due to heat.
The 10811 output is specified as 0.6 Vrms max into 50 ohms, or 7.2
mW. I doubt that heating-induced resistance change was a significant
problem. But no harm changing it.
Best regards,
Charles
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