[time-nuts] Frequency referenced temperature regulator

[Poul-Henning Kamp]

I'm contemplating building a small temperature control enclosure for
testing various electronics.

I have a handful of peltiers suitable for the purpose, and was
pondering the right control mechanism.

Most people would reach for a NTC, put it in a wien-brige etc etc.

But since I happen to have access to much more stable frequencies
than voltages, I thought of a different way:

1. Mount a X-tal-osc with really lousy tempco inside the enclosure.

2. Compare its output to a stable reference frequency.

3. Use the output of the phase comparator to drive the Peltier.

It is basically a PLL where temperature is used as EFC...

Has anybody tried that ?

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