Hi What we are talking about is toggling the least significant bit in the DDS to achieve a resolution of less than that LSB. It could be done to a set period (like a PWM) or pseudo randomly to reduce the noise signature. Either way, roughly a 16 element long "period" should be quite adequate. 7x10^-16 / 16 would give us a 4x10^-14 step and a 2x10^-14 max error.
Bob On Jan 13, 2012, at 4:30 PM, Don Latham wrote: > Oh, I hate to be a pedant, but are we talking about dithering, that is > random perturbations to remove things like hysteresis, or using the > finite steps as a bang-bang servo? > Don > > Charles P. Steinmetz >> Bert wrote: >> >>> wrong there is no DAC involved, it is a DDS >> >> Ahh. Not so simple, then. I still don't much like the notion of >> dithering, but it may be the only alternative. Or, as has also been >> suggested here, add a manual C-field adjustment (but that would not >> change the fact that the RS-232 adjustments would still be ~ 7e-13 >> steps). >> >> Best regards, >> >> Charles >> >> >> >> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > -- > "Neither the voice of authority nor the weight of reason and argument > are as significant as experiment, for thence comes quiet to the mind." > R. Bacon > "If you don't know what it is, don't poke it." > Ghost in the Shell > > > Dr. Don Latham AJ7LL > Six Mile Systems LLP > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > www.lightningforensics.com > www.sixmilesystems.com > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
