Hello Bob, If you think you are getting any high frequency into the EFC control - it may be worth putting a(nother) low-pass filter in there. Are you measuring noise on that line?
Do you have a snap-shot of a schematic? Or, can you take a picture of that circuit? I would hazard a guess you don't want to change the op-amp in such a way the gain is too high - the circuit could be designed for unity gain. A different choice in resistors could still yield unity gain and maybe knock down the noise a bit. I would need to put an ammeter in the circuit to determine if there was any meaningful current flow - without injecting noise of course... ;) 73's, John AJ6BC On Wed, Nov 6, 2013 at 7:26 PM, Bob Stewart <b...@evoria.net> wrote: > I think I may need to change the LPF feeding the EFC in my GPSDO to get > rid of dithering jitter. Is there any point in adding a resistor and cap > in the EFC line, or do I need to go back and change the values in the > op-amp circuit feeding it? Currently an op-amp directly feeds the EFC > pin. I guess this boils down to something like: is there any meaningful > current flow in EFC circuit in this oscillator? Or should I add them but > will I probably have to change the existing filter, as well? > > Bob - AE6RV > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.