Re: [time-nuts] Small basket
Are you referring to Kalman filtering/steering? Yes, it depends on how accurate is the model of the oscillator (and the dimensions of the Kalman filter) but it can work for several hours not indefinitely. On 10/13/11, Chuck Harris wrote: > Because the aging of oscillators is sufficiently random that it defies > prediction over the long term. Austron, and others, have made disciplined > oscillators that calculated the aging rate relative to a stable source, > and applied that correction to the oscillator's EFC if the stable source > went away... It works for several hours at most before the stubborn little > oscillator, and the aging model diverge. > > -Chuck Harris > > Perry Sandeen wrote: >> List, >> >> Wrote: I wonder how long it will be before the only remaining basket of >> will >> suffer a catastrophic fall. >> >> The U.S. satellite system, AFAIK, is not guaranteed for high accuracy to >> civilians >> and also is vulnerable to foreign interference/destruction. >> >> Perhaps while we have it as it is now, it might be prudent to accurately >> track the >> EFC voltage over time that one needs to maintain a particular oscillator >> to it >> maximum stability. >> >> Then make an independent oscillator and divider chain that will cycle a >> digital >> potentiometer taps or perhaps a DAC to automatically maintain the rate-of >> - change >> needed to keep said oscillator at maximum stability. >> >> Doing this now with at least one or two oscillators and then comparing to >> a GPS >> derived frequency and least gives one a “belt and suspender” back-up. >> >> High quality 10 MHz oscillators are available all day on epay for less >> than $50. >> Or one could splurge on a HP 10811 or Rubidium for less than $100. >> >> Just food for thought. >> >> Regards, >> >> Perrier >> >> >> >> >> >> ___ 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.
Re: [time-nuts] Small basket
Because the aging of oscillators is sufficiently random that it defies prediction over the long term. Austron, and others, have made disciplined oscillators that calculated the aging rate relative to a stable source, and applied that correction to the oscillator's EFC if the stable source went away... It works for several hours at most before the stubborn little oscillator, and the aging model diverge. -Chuck Harris Perry Sandeen wrote: List, Wrote: I wonder how long it will be before the only remaining basket of will suffer a catastrophic fall. The U.S. satellite system, AFAIK, is not guaranteed for high accuracy to civilians and also is vulnerable to foreign interference/destruction. Perhaps while we have it as it is now, it might be prudent to accurately track the EFC voltage over time that one needs to maintain a particular oscillator to it maximum stability. Then make an independent oscillator and divider chain that will cycle a digital potentiometer taps or perhaps a DAC to automatically maintain the rate-of - change needed to keep said oscillator at maximum stability. Doing this now with at least one or two oscillators and then comparing to a GPS derived frequency and least gives one a “belt and suspender” back-up. High quality 10 MHz oscillators are available all day on epay for less than $50. Or one could splurge on a HP 10811 or Rubidium for less than $100. Just food for thought. Regards, Perrier ___ 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] Small basket
List, Wrote: I wonder how long it will be before the only remaining basket of will suffer a catastrophic fall. The U.S. satellite system, AFAIK, is not guaranteed for high accuracy to civilians and also is vulnerable to foreign interference/destruction. Perhaps while we have it as it is now, it might be prudent to accurately track the EFC voltage over time that one needs to maintain a particular oscillator to it maximum stability. Then make an independent oscillator and divider chain that will cycle a digital potentiometer taps or perhaps a DAC to automatically maintain the rate-of - change needed to keep said oscillator at maximum stability. Doing this now with at least one or two oscillators and then comparing to a GPS derived frequency and least gives one a “belt and suspender” back-up. High quality 10 MHz oscillators are available all day on epay for less than $50. Or one could splurge on a HP 10811 or Rubidium for less than $100. Just food for thought. Regards, Perrier ___ 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.
