Hi You can do very much the same thing by getting an SC to run on both the B and C modes at the same time.
Bob On Nov 8, 2010, at 6:04 PM, Magnus Danielson wrote: > Poul-Henning, > > On 11/08/2010 04:04 PM, Poul-Henning Kamp wrote: >> >> 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 ? >> > > Have a look at "microprocessor compensated crystal oscillators". It runs the > oscillator in both basic and third overtone at the same time. By measuring > the beat frequency between the modes, the temperature can be measured. > > See the John Vig presentation > http://www.am1.us/Papers/U11625 VIG-TUTORIAL.PDF > starting at page 43. > > I see no reason why it could not be used to stabilize the temperature. > > Cheers, > Magnus > > _______________________________________________ > 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. _______________________________________________ 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.
