Could you plz. plot drift (with the drift rate itself removed for sure) vs. ambient temperature? Is it just me or is there a small correlation?
I have drawn values over temperature from day 705 where the drift is rather stable.
I see no direct correlation drift over temperature on the ADR1000 measurements.
(the T.C. is adjusted to -6 ppb/K and -4.5 ppb/K on the 6.6V outputs and +20 ppb/K on the 10V output).
https://www.eevblog.com/forum/metrology/lowest-drift-lowest-noise-voltage-reference/msg5138967/#msg5138967The ageing measurements on ADR1000A are always corrected by a LTZ#4 measurement.
(my most stable reference over time with -21 ppb/K)
So also the temperature coefficient of the 4 ADCs + both DMMs are corrected.
But I have to admit that this reference measurement on LTZ4 is the weak point.
If it fails, you have a common cause error which is also visible in LTZ#9 measurement.
When you look at the "dent" on day 726 it is not temperature related.
In the averaged measurements of the raw values on 15.03.2024 I can see that ADC#15 and ADC#17
measurement failed for some reason on LTZ#4 compared to 08.03.2024.
(not temperature related, probably bad contact or EMI related during measurement)
So normally I should exclude this measurement on day 726 from data.
with best regards
Andreas