[time-nuts] Fury Interface Board: How about TI OPA277?

John Miles jmiles at pop.net
Fri Nov 2 19:55:57 EDT 2007


> > The Achilles' heel of this technique is the statistical temperature
> > fluctuations experienced by individual resistors.
> > ...

Seems debatable whether it's worth worrying about details like this when the
EFC signal is just going to go straight into a 20K-100K resistor in the
OCXO, isn't it?

I just use a simple resistor network to drop the bipolar DC EFC control
voltage from my 11729C to the level needed by the 10811A in my 8662A, and I
have no problem making measurements at the 10811A's specified noise floor,
at least from 100 Hz and beyond.  I suppose 1/f and popcorn noise is still a
concern, but surely that's dominated by the relatively-large resistance
between the EFC control loop and the varactor.  No?

-- john, KE5FX




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