Hi If you attenuate the DAC 100:1 to 1000:1 before it hits the OCXO, the DAC does not matter much. That may sound like a crazy ratio, but it is indeed possible with some of these OCXO EFC ranges. They can have a *lot* of swing.
The reference is an LTZ1000, they run about $50 in single piece lots. You can get resistors that run below 1 ppm tracking without a whole lot of effort Bob On Jan 31, 2014, at 8:38 PM, Robert LaJeunesse <rlajeune...@sbcglobal.net> wrote: > Must be military prices. If using 5 PPM resistors in the build a reference > much better than that isn't needed, especially if the temperature is somewhat > controlled, like time nuts do. A commercial 3 PPM/C part, the LM4140A, is > $4.54 each in singles. At 2.2uV p-p it's reasonably quiet as well. > > Considering stability influences, what provides the DAC reference? That's > rather important as well. > > Bob LaJeunesse > > I'd also note the 2 PPM ratio tracking dividers, the MAX549x series, can be > had in the $3.49 range, also not all that expensive. > > > >> ________________________________ >> From: Bob Camp <li...@rtty.us> >> To: Bob Stewart <b...@evoria.net>; Discussion of precise time and frequency >> measurement <time-nuts@febo.com> >> Sent: Friday, January 31, 2014 7:17 PM >> Subject: Re: [time-nuts] EFC divider resistors >> >> >> >> ... A good voltage reference will set you back about $50 or so. >> > _______________________________________________ > 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.
