[time-nuts] Regarding the improved integrator A9 in the 5065A...

Ulf Kylenfall ulf_r_k at yahoo.com
Thu Dec 28 15:35:45 UTC 2017


 Regarding the improved integrator A9 in the 5065A
Rubidium FStandard. (Series 2632)
I have copied some of the improvements (?)that HP made to the 5065. The A7 AC-Amplifierand the A9 Integrator. Regarding the A9 Integrator:
I noticed that there is nothing that prevents
the [-EFC] signal from going positive in the
improved OPA111 design. 
If the XO in the 5065A
is an old 00105-6013, the series resistances
to the varactor in the XO Assembly
amounts to ~70 kOhms which should prevent the
varactor CR1 from forward current destruction.
In the 10811-version I can see 100 kOhms.
How does these oscillators behave should the
-EFC signal swing the full +/- 15V that the
OPA111 is capable of? Does it stop oscillating?


Will 15V reverse polarity destroy the varactors?

I have added two zener diodes to the output
after R3 (21K5) in my design which will 
prevent the [-EFC] from exceeding +/- 5V 
but the question is if the diodes needs 
to be populated or not.

Comments Invited.

Ulf Kylenfall
SM6GXV


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