Hal Murray writes: > e...@thyrsus.com said: >> I have a USB thermometer on order, they're cheap. Might I suggest you get >> one and repeat this experiment, actually plotting your temperature >> variation? > > Most CPU chips include a temperature sensor. > > For Linux PCs, you need the coretemp module loaded. The lm-sensors package > does that. > > You can get it by either parsing the output of the sensors command or by > looking in things like > /sys/devices/platform/coretemp.0/hwmon/hwmon0/temp2_input
I've checked the loopstat data from last week and both my rasPi get steered less than +-1ppm from their baseline of -6ppm and -9ppm with a temperature swing of about 4K over the day. I can see when the sun was hitting the roof and when I've had open windows, so I'm pretty certain this is real. You'd need a thermometer that does at least have repeatability down to 0.25K to get something useful out of the temperature data. If you can get repeatability down to 10mK, then it'd probably be possible to forward-compensate the temperature effects to below 5ppb, giving you holdover capability for around 5 hours. Regards, Achim. -- +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ SD adaptation for Waldorf microQ V2.22R2: http://Synth.Stromeko.net/Downloads.html#WaldorfSDada _______________________________________________ devel mailing list devel@ntpsec.org http://lists.ntpsec.org/mailman/listinfo/devel
