[time-nuts] FE-5680A Mechanical Question
lists at rtty.us
Fri Jan 13 17:02:31 EST 2012
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.
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?
> 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
>> Best regards,
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> 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
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the time-nuts