[time-nuts] Disciplining Rubidium

[John Miles]

> The actual FRS-C is quite a bit cleaner but still nowhere near as good as
> the Thunderbolt.
>
> Also worth noting is that the Datum's output is quite a bit
> noisier than it
> was several months ago when I measured it with (very) different
> hardware.  I
> wouldn't take the green trace in this graph to the bank until I've had a
> chance to repro that earlier measurement.  Still, either way, it's
> definitely much noisier than the Thunderbolt.

My mistake - there's no meaningful difference, it's within 2 dB of my
earlier measurement on the 11729C.  I think I was confusing that trace with
the FSC-C rubidum measured by itself, which is good for a floor between -135
and -140 dBc/Hz.

-- john, KE5FX