I'm not sure what the Z3801A uses for EFC range. Heather uses the EFC relative command to report the EFC setting. That command reports values from -100% to 100%. There is a command that reports the DAC input in counts, but nothing documented that shows volts/count. Since the DAC is at -2V with a 99+% DAC setting, it looks like the DAC circuit has issues, or power supply problems. I think the DAC circuit is a 16 bit DAC with 4 more bits of resolution created by dithering the DAC inputs.

Hi The control range should be +/- 5V if I remember correctly. If it’s not, the only other standard would be 0-5V. There is zero logic in running a wider swing mod to an OCXO at a lower EFC range. It indeed sounds like the DAC has trouble. Bob > On Mar 6, 2018, at 1:24 AM, Mark Sims <holrum@hotmail.com> wrote: > > I'm not sure what the Z3801A uses for EFC range. Heather uses the EFC relative command to report the EFC setting. That command reports values from -100% to 100%. There is a command that reports the DAC input in counts, but nothing documented that shows volts/count. > > Since the DAC is at -2V with a 99+% DAC setting, it looks like the DAC circuit has issues, or power supply problems. I think the DAC circuit is a 16 bit DAC with 4 more bits of resolution created by dithering the DAC inputs. > _______________________________________________ > 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.