[time-nuts] 10MHz Rubidium reference source for frequencycounter
Charles Steinmetz
csteinmetz at yandex.com
Mon Nov 3 15:43:47 EST 2014
Tom wrote:
>As I understand it, his project is to use the high frequency output
>of a ublox NEO-7M to discipline a MV89 with a James Miller-style analog PLL.
> * * *
>(perhaps someone can post an English translation for us)
Tom,
I have a machine-translated PDF (~2.5MB), but nowhere to put it
up. If you have web space for it, please feel free to do so
(assuming that Karen does not object).
I have reservations about the potential of any Miller-style GPSDO,
because using an analog PLL essentially guarantees that the crossover
to GPS will be at a tau orders of magnitude lower than it should be
-- the Miller unit crosses over about 3 OOM too low (see attached
plot, from <http://www.leapsecond.com/pages/gpsdo/>).
The beloved Thunderbolt also crosses over about 2.5 OOM too early, if
you use the factory loop settings (id.). But it has an ADPLL with
adjustable parameters, so a time nut can tune the loop for best
performance with the particular OCXO in the unit. (See
<http://www.ke5fx.com/tbolt.htm>.)
Best regards,
Charles
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