[EMAIL PROTECTED] wrote: > Hi Bruce, > > > in an 'uncontrolled' environment like that one would not get 2-20ppm retrace > on the Zener (as speced in the table sent to this group earlier) I would > think. > > bye, > Said > Said
Yes it could be worse. What I'm trying to show is that the thermal environment of the EFC reference and DAC is important as is their noise. Just low pass filtering a PWM waveform whose amplitude is determined by a noisy supply regulator, as some do, is just too noisy to obtain optimum performance from a 10811 or equivalent performance OCXO. Of course one can always resort to annealing out the retrace by controlled thermal cycling of the reference as Fluke (optionally) do in their 7000 series references whenever continuous power is lost. These 10V references use selected LTZ1000's to achieve a drift of around 1ppm/year. Bruce _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
