[time-nuts] Primary Time Standards
phk at phk.freebsd.dk
Fri Jul 15 08:16:42 UTC 2011
In message <AC0EA5F6-DDBF-49D4-A576-03BD7F91A15D at leapsecond.com>, "Tom Van Baak
>> Absolutely, but you can still pull a new Cs out of the box and it will
>> run at the same frequency as your old Cs.
>Not quite "the same". This is called the re-trace spec which is
>poorer than the stability spec. Vintage Cs standards like the 5060
>or 5061 powered up within about 1e-10 or 1e-11. The 5071A retrace
>spec (called reproducibility in the data sheet) is 1e-13.
Right, but this is again not because of the physical principle used,
but because of the implementation of it.
The reason Rb's are secondary, is because the physical principle
has no "nominal" frequency, but only an approximate one.
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