Poul-Henning Kamp wrote: > 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 ?
Frequency comparison between two oscillators, one a low-tempco and the other a high-tempco, is used by Dallas in the new version of the infamous (to Time Nuts) DS1620 temperature sensor. See the current datasheet and Dallas AN-105. I assume neither is an XO, nor do they phase lock them. Instead, they count the higher-frequency, low-tempco oscillator using the lower-frequency, high-tempco oscillator as a time base, then correct for nonlinearities.
Best regards, Charles _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
