[time-nuts] Yb clock - stability estimation procedure?

Bob Camp lists at rtty.us
Wed Aug 28 11:00:24 UTC 2013


Hi

The commonly heard comments about common mode drift very much pre-date the 5071…

Bob

On Aug 27, 2013, at 5:57 PM, Richard Karlquist <richard at karlquist.com> wrote:

> On 2013-08-27 13:35, Florian Teply wrote:
> 
>>> No, HP did not make the long tube Cs standards at NIST (as the NIST
>>> guys always love to point out) and they are very different animals
>>> than the ones you can buy. So, the international definition of the
>>> second has always been safe from manufacturer induced common mode.
> 
> I vaguely remember the NIST guys wanting to copy some of the HP
> electronics from the 5071A.  So don't be so sure.
> 
> Regarding common mode environmental drift:  When the 5071A was
> introduced, an extensive set of tests was performed over the
> better part of a year to determine common mode environmental
> drift.  The measurements were sensitive to parts in 10^15.
> No environmental sensitivity whatsoever was measurable.
> This was no accident, but rather the result of careful design.
> OTOH, the 5061 could change frequency noticeably by just removing
> the top cover.
> 
> Whatever the merits of the big iron Cs standards, the fact of
> the matter is that after the 5071A was introduced and they got
> into circulation, as a group, they accounted for upwards of
> 80% of the weight of the TAI.
> 
> 
> Rick Karlquist
> N6RK
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the Time-nuts_lists.febo.com mailing list