Dave wrote:
I set the temp scale to 250m°C/div last night and it remained steady for quit a while, but then it started the jumping again. It seems to jump on 1° increments, like from 37.750 to 38.749 in less than 1 minute, but there are step variations during the 1° movements.
I do not know whether LH just displays every "n-th" sample to produce long-time-scale plots, or whether it averages "n" samples to get the displayed value. If it averages, each pixel would include data from more than one sample, which would produce intermediate values that the GPSDO did not actually report. You may want to set the time scale so you can see each one-second sample (I think one minute per division will do this). At that scale, you may find that all of the samples are in one degree increments. In other words, the appearance of intermediate values may be an artifact of display averaging -- the actual data from the GPSDO may be strictly in 1v increments. Mark could say for sure.
So what you're saying is it won't affect the freq stab or adev?
We (the time-nuts community) do not have hard data about how the temperature data is used in the Trimble GPSDOs, but it appears that it is not used during locked operation except to "teach" the unit about the OCXO's temperature coefficient. What it has "learned" is applied during holdover in an attempt to improve holdover stability. I doubt many time nuts would make critical measurements while their GPSDO was unlocked, so there is probably no practical difference as far as we are concerned.
Best regards, Charles _______________________________________________ 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.
