On Tue, 09 Dec 2003 17:28:22 -0700, Jim Thompson
wrote:


Paul, That will work, but will double *both* min and max capacitance.
But I'm puzzled: "I can't get enough shift with the available bias
voltage" implies you're on the *low* end of capacitance (highest
voltage).

I'm using a 555 timer to generate a sawtooth waveform to feed the
diodes, so I get a constant frequency sweep at the vcxo's output. Main
problem is the limited voltage output range; starts above zero volts
and peaks well before supply rail. So not much of a ramp; just around
4 or 5 volts, I guess. I could try changing the diodes for more
responsive ones but they're SMDs and I really hate messin' with 'em.
:-(
--

"I expect history will be kind to me, since I intend to write it."
- Winston Churchill