Ed Palmer-"Every oscillator has a spec for frequency shift due to power supply
variation,
but maybe you'd see a big change when you lost regulation. Have to think about
that."
I have done this a few times with oscillators that contain internal regulators
and the output
level remains constant and the frequency display on my scope (triggered by a
standard)
remains stable until you reach the point where the internal regulator output
starts to drop
and you do see a significant change. Because the oscillator and buffer stages
generally
only draw a few ma., a low power linear regulator with good filtering is easy
to design.
HP says this about the simple circuit they used in the 10811:
"8-25. VOLTAGE REFERENCES (5.7V AND 6.4V)
8-26. Constant current diode CR2 feeds 1 mA to zener diode CR3 providing
6.4Vdc for the
EFC varactor reference. R12 and C15 form a filter to attenuate noise from the
zener
diode."
As to the -12VDC supply, one unit that used the Thunderbolt used -7VDC instead
of
-12VDC and the same Thunderbolt works just fine with either voltage.
-Arthur
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
