wrong there is no DAC involved, it is a DDS In a message dated 1/13/2012 3:36:33 P.M. Eastern Standard Time, charles_steinm...@lavabit.com writes:
Bert wrote: >we would be talking +- one step and using different rate but reading the >frequency over 1000 seconds would be my answer. Rather than dithering the existing 7e-13 steps, perhaps it would be simpler to adjust the 5680A step size? Presumably, the C-field is being controlled by the current or voltage output of a DAC, and the 7e-13 steps represent the LSB of the DAC. From the reports so far on the list, the DAC output range is much larger than necessary (I think someone said ~ +/- 2 Hz ??). If you attenuate the DAC output by 10x in the analog domain, you would have a +/- 0.2 Hz range with 7e-14 steps (or, if you like, attenuate by 7 for 1e-13 steps, or by 14 for 5e-14 steps). You would have to be a little careful about the tempco of the implementation (particularly, you may need to add some low-tempco bias to get the range centered on 10.000000000 MHz again), but I wouldn't think it would be so critical as to be beyond the ability of the home time nut. Best regards, Charles _______________________________________________ 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.