On 6/2/17 2:51 PM, Donald E. Pauly wrote:
This is an improvement of 476 to 1. You apparently have not thought thru what improvements are possible with thermal coolers/heaters. Among these is near instant warm up and greatly reduced power for thermal management.
without getting into the whole crystal issue, one of the advantages of a heater is that it can be VERY simple (and hence reliable, just on a parts count basis). With a decent package, once it's hot, the power required to keep it hot can be quite low.
With a heat/cool, you need to be able to have a bipolar supply to the peltier device, and they're not particularly efficient (that is, to extract 1 Watt of heat, you're putting in significantly more than 1 watt of DC, and rejecting 1+X watts to the outside world.
And then, if you use a linear power supply/amplifier to drive the device, that is probably a class A device, and somewhat lossy. A switcher would be more efficient, but then you have the problem of switching noise, in close proximity to the crystal. You could put a big low pass filter in, but now you're adding even more components.
There are undoubtedly some cases where the thermoelectric scheme would work better - for instance, you have a system with a TCXO and it's really set up for the TCXO to be at 25C, and you want to regulate that.
_______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
