[time-nuts] CSAC Project(was CSAC purchase)
ronaldheld at gmail.com
Wed Jan 24 15:59:21 EST 2018
One around 1s/y, one 6 s/y and one 11 s/y. I was looking to do
better than 1 s/100 years, but that was for the CSAC.
1 second/year is quite good - about 30 ppb. It's a bit tricky (like all
things time-nutty) - the "aging" on a TCXO could be that good - but the
instantaneous frequency control might not be that good. 1ppm is pretty
vanilla for a TCXO over a fairly wide temperature range, so 30 ppb at
"constant skin temp" (say, 5 C range) is probably reasonable.
I've got some test data here for some fancy TCXOs intended for space
with a spec of 2ppm aging first year and then 1ppm/year after that. The
actual aging in the first year was 0.08 ppm, at 70C. Some of the other
oscillators in the lot were 0.02ppm, 0.05ppm.
So, I think the spec here is "covers all the things that can go wrong",
but by cherry picking, you could do better.
(or, our system design could tolerate several ppm aging over years, and
"run of the mill" for Vectron was actually a lot better)
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