Hi Even if you *do* have a number for your OCXO EFC, what is that number?
The nominal sensitivity is fine. The next layer is the ratio of maximum slope to minimum slope. This is a very different thing than the “linearity” that is normally specified. Even the linearity is something you need to look carefully at the Mil-O-55310 definition. It’s not quite what you would expect it to be. Bottom line: the sensitivity can easily vary 2:1 or even 4:1 on a pretty good part. Bob > On Apr 15, 2022, at 5:13 PM, Skip Withrow <skip.with...@gmail.com> wrote: > > One of the things that cannot be ignored are the statements made in > item #10 regarding the DAC and OCXO EFC. If the DAC is 16 bits that > is 2^16=65,536 steps. If the DAC outputs 0-4 volts that is 61uV/step. > > Now you have to take this number and multiply it by your OCXO > sensitivity (not given), and you have the minimum frequency step that > can be made. > > This is the best that you can ever do. So, your TIC/1pps resolution > does not need to be any better than this. Waiting a long time to get > higher resolution may (probably) buys you nothing. > > This is where all the magic comes in - higher resolution DACs, more > stable oscillators, more stable GPS PPS, etc. > > To a first order, overlaying the line from item #6 with the ADEV of > the oscillator used and setting the loop time constant at the > crossover tau works pretty good. > > As has been said many times, if it was easy everybody would be doing it. > > Regards, > Skip Withrow > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.