[time-nuts] HP Z3801a piezo oscillator does work

paul swed paulswedb at gmail.com
Sun Dec 18 16:36:44 EST 2016

OK the 10 MHz Piezo oscillator from a lucent RC/xtal pair does work and the
3801 is doing what it should.

Some insights as mentioned. 3801 DAC being full scale is not an issue when
a good signal within 2 HZ is used it will come out of limit.

The DAC output was driving the piezo far to widely I added a 10:1 V
antennuator to reduce the swing. The piezo requires a positive only EFC and
its control is inverted as compared to the HP 10811. Used a single TL071
opamp to invert the signal and apply the offset. By calculations it should
have been offset to 3.6V but the system seems to want 2.5V. Pretty sure an
adjustment on the actual oscillator would fix that.

I can now see that something like an RB could be plugged into the 3801 etc.

But more important the proof is that the actual Z3801 is fully functional
and the only bad thing is a the HP 10811 oscillator.
Its been a great learning exercise. How to get rid of teh outer oven. How
to use far simpler power supplies to run the 3801 instead of the 48 volt
Overall a lower power consumption solution can be built.

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