Mark, Everyione else on the list seems to be paddling their own canoes lately and may not have spotted your query.
Yes, you most surely can use an external EFC voltage to control this device. You will need to learn what's connected inside, and I suspect there will be a precision reference and resistor to the pin, and then the user provides a resistor to ground on the outside. Find out by measuring the open-circuit voltage, then by pulling the pin to ground with a milliameter and determining what current flows. Then use Ohms Law to work out the Thevenin equivalent source. If the source impedance is fairly high, simply drive the oscillator EFC from an external source. If it's lowish, consider putting a pot to ground that puts the oscillator on frequency, and driving the pot/pin junction with a low source impedance. I've taken this approach with the Morion MV89. Either way, the external drive will need very stable, noise free, and use a very good reference. There's another possibility I've not tried, and that's to use an electronic resistor. I don't mean one of the steppable EEPROM type, but simply a current mirror or transconductance amplifier. 73, Murray ZL1BPU _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
