Hi All these devices *can* be sensitive to the environment. What degree of sensitivity they have is a function of how “nutty” one went on this or that design. It also is a function of things like cost, size, and power consumption.
The target market for things like the 5071 is a “we can afford it” sort of crew. Even today various government agencies from various countries buy the bulk of the 5071’s produced. Yes sorting this out is a bit complicated. Multi step procurement is pretty common. Telecom Rb’s and OCXO’s normally go into a *very* different market. There is indeed a “good enough” point at which the willingness to pay goes away. Temperature stability is one of many things that could be better if more money / power / volume was thrown at the problem. So no, not a simple single answer. Bob > On Nov 29, 2021, at 9:55 AM, Lux, Jim <[email protected]> wrote: > > On 11/29/21 1:57 AM, Hal Murray wrote: >> [email protected] said: >>> And a lot ofsources may have a low flat spot in the curve, but it >>> eventually trends up. Except for primary standards like Cs beam. >> What's magic about "primary standard" or "Cs beam" that keeps the ADEV from >> trending up? >> > Their ultimate accuracy is dependent only on a invariant physical property > that is independent of time. > > A quartz crystal ages. No matter how good your oven is, the frequency will > change over a long time. > > Mercury ions, Cs ions (perhaps all ions?) have frequencies that are a > fundamental property of the ion. There might be practical implementation > limits or side effects that limit the lowest achievable uncertainty - hot > atoms will have higher variance than cold atoms, for instance. So not all Cs > primary standards have the same ultimate performance. > > > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send an > email to [email protected] > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
