[time-nuts] Some additional RTFG learnings
phk at phk.freebsd.dk
Tue Feb 20 14:42:58 EST 2007
In message <BAY128-DAV24A97F6CDE3EAAA48530DA9890 at phx.gbl>, TheInfamousFlavio at ho
>1. there is the unit is putting voltage to the electronic cfield connector
>of the rb oscillator.
It is not unlikely that there is a DAC for that voltage so that
factory and field calibrations can be done from a remote location.
The Rb is what telecoms people call "a green light box": You mount it,
plug it in, see the light turn green and you're done.
The Rb is inside spec for the telco application without discipline and
therefore adding discipline would reduce the MTBF of the Rb, since
a failure in the source, PLL or DAC would result in it going off spec.
It is probably possible to monitor the Rb/GPS delta-T remotely, and
_maybe_ they will manually tweak the C-field DAC once per year or so.
They like Cs even better than Rb, because they are guaranteed inside
spec for 10 years, provided the green light doesn't turn off.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
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