Hi There *has* been a lot of research into these functions. The Frequency Control Symposium archives have at least a few dozen papers on the why and how of the functions working. They are now behind a paywall for me so those who have the luxury of access will have to dig for them on their own.
Bob > On Nov 24, 2016, at 5:03 PM, Scott Stobbe <scott.j.sto...@gmail.com> wrote: > > Sadly I don't think there is a concise answer to this, in reality you would > make the decision on the fly depending on how much data you have and which > model is the most well behaved. > > I think it's a really interesting topic to see some of what goes into an > OCXO, a guaranteed limit on aging is one the many things. > > Part of the reason that information on the topic is somewhat is scattered, > is if a commercial application genuinely needed 1e-12 stability for 100 > days free-running, the answer without hesitation would be atomic. Then as > you dial back the long-term stability requirement how much NRE are you > willing to spend; which is also why there doesn't seem to plenty of worked > examples out there. > > On Thu, Nov 24, 2016 at 10:49 AM, Attila Kinali <att...@kinali.ch> wrote: > >> On Thu, 24 Nov 2016 08:16:08 -0500 >> Bob Camp <kb...@n1k.org> wrote: >> >>> If you take the bad aging (out of spec) parts out of the pile, those are >> the ones >>> with the best fit. They have very pretty curves and they stick to those >> curves >>> for a *long* time. They have a single dominant cause for their aging ( = >> the defect). >>> The rest of the parts have all of the causes bashed down by the process >> so that >>> over a 20 or 30 year span, there probably is no single dominant cause. >> >> Then the question becomes: What would be a good fitting function for >> the typical application of an OCXO that is regularly measured with >> not too long time spans (e.g. GPSDO)? From the discussion it seems >> that a second or third order Taylor would be sufficient to capture >> aging for a span of 10-100 days. >> >> Attila Kinali >> >> -- >> It is upon moral qualities that a society is ultimately founded. All >> the prosperity and technological sophistication in the world is of no >> use without that foundation. >> -- Miss Matheson, The Diamond Age, Neil Stephenson >> _______________________________________________ >> 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. _______________________________________________ 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.