Also you need a super ultra fantastic voltage reference for a 32bit DAC. Anyway, yes, in my GPSDO the controller has 3 levels: at startup is fast, then slow and then very slow. The levels trigger when the precision estimate is 10E-9 and 10E-11. If you have a resolution of 10nS then take 10 averages and your resolution will be 1nS and so on. When I switch level, the number of averages is increased too but this leads to a slower DAC update rate. This is the problem: now I'm trying to figure out if the corrective action can be "predicted" (Kalman filtering) and applied at the same speed.
On Fri, Sep 14, 2012 at 8:52 PM, Chris Albertson <[email protected]>wrote: > On Fri, Sep 14, 2012 at 11:21 AM, Michael Tharp > <[email protected]> wrote: > > > Finally, do people think a 16 bit DAC is adequate or should I consider > > building a 32-bit one? I looked at a few designs when putting this > together > > but decided to keep it simple until things were up and running. > > Having a 32-bit DAC would give you enough range so that you could drop > in any OCXO you might have. But if you can have trimmer resisters to > selected for your specif OCXO then 16-bits should be enough. If it > were me, I'd want the DAC steps to be smaller than what the phase > detector can measure. Said another way a 32-bit DAC might > eliminate the need for scale and offset trimmer resistors. > > Chris Albertson > Redondo Beach, California > > _______________________________________________ > 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.
