Capacitor matching (Moore's law) has improved for switch-cap designs. Also depends on the tuning gain, 10 ppm/V would be very demanding versus 10 ppb/V.
On Thu, Jul 21, 2016 at 9:47 PM, Richard (Rick) Karlquist < rich...@karlquist.com> wrote: > > > On 7/21/2016 4:56 PM, Nick Sayer via time-nuts wrote: > >> Oh my. That’s a bit more than I was originally considering… What I had in >> mind was adding a DAC front end to an OCXO so that you could tune the EFC >> with serial commands rather than analog and calling that a product. >> >> > 20 years ago when HP was working on a so called "smart clock" > GPS box, they decided to do what you said, use a DAC to > tune the EFC on the E1938A oscillator. I > recommended to them NOT to try to do that, but they > didn't listen to me. At that time, it > was nearly impossible to come up with a DAC, buffer > amplifier, and voltage reference that didn't degrade > the stability of the E1938A, which isn't even as stable > as a 10811. What you need to ask yourself is: in > 2016, can I finally get analog components that are > an order of magnitude or two better than what was > available in 1996? I don't know, without researching > it. Certainly, we can't depend on Moore's law coming > to the rescue. If anything, that works against analog > IC's by obsoleting older analog processes. > > Also in 1996, phase microsteppers were already legacy > technology and didn't have a good reputation for spectral > purity. Another non-panacea. > > Rick > > _______________________________________________ > 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.