So why would they not show the same kind of jumps as plain OCXO's? Rick K. mentioned atomic standards avoid jumps. Bob Q. ----- Original Message ----- From: "WB6BNQ" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" <[email protected]> Sent: Thursday, October 23, 2008 3:42 AM Subject: Re: [time-nuts] Question on crystal jumps
> Hi Bob Q, > > Yes Rubidium (Rb) and Cesium (Cs) standards use OCXO's. > > I suppose the way to look at it is the Rb or Cs chamber acts as an > invariant > atomic filter with extremely narrow bandpass (i.e., with an extremely > high Q). > The resonant frequencies of these atomic filters are up in the microwave > regions > and thus do not lend themselves easily to direct comparison. So, a high > quality > standard frequency oscillator is locked in a loop controlled by the > atomic > filter. The OCXO's output is the reference signal out of the atomic > standard. > > I hope this rather simplistic overview answers your question ? > > Bill....WB6BNQ > > Bob Q wrote: > >> Do rubidium standards use an OCXO? >> Bob Q. >> >> ----- Original Message ----- >> From: "Rick Karlquist" <[EMAIL PROTECTED]> >> To: "Discussion of precise time and frequency measurement" >> <[email protected]> >> Sent: Wednesday, October 22, 2008 2:23 PM >> Subject: Re: [time-nuts] Question on crystal jumps >> >> > I'm not quite sure what the question is here, but when >> > we made 10811 oscillators at HP, "jumps happened". Some >> > crystals were better than others, but no crystal was immune >> > from jumps. With good quality crystals, you might be able >> > to put an upper bound on the magnitude of jumps, like 10-9, >> > but not on the time between jumps. I also noticed that there >> > didn't seem to be any correlation between jump activity >> > and stability between jumps. You could have an oscillator >> > with really low aging, say a few parts in 1E11 per day that >> > looked really good for quite a while, but then the frequency >> > jumps. After you've controlled everything you can about the >> > crystal process, the electronics, the oven and the environment, >> > you are still left with jumps. If you want no jumps, go to >> > an atomic standard like rubidium. There are mechanisms that >> > can cause jumps in rubidium standards as well, but good >> > rubidium standards don't jump. >> > >> > Rick Karlquist N6RK >> > >> > >> > [EMAIL PROTECTED] wrote: >> >> I would be very pleased to know when (date and time) anybody >> >> out there happened to record jumps in frequency of crystals. >> >> I have stable (e-07) tuning forks which happen to jump too, >> >> and I don't understand why, even having under control >> >> temperature and air pressure. Sometimes they return to their >> >> prior frequency with another jump, and this could happen even >> >> days later, sometimes they jump and then recover smoothly the >> >> prior frequency in a short time (such as one hour). >> >> I have no idea whether any correlations would exist between >> >> crystals and tuning forks jumps, regarding the causes that >> >> could trigger metastability, and hence I would have a look at >> >> crystal data in order to improve the base for future >> >> speculation. >> >> >> >> Thanks in advance. >> >> Antonio I8IOV >> >> >> >> >> >> >> >> _______________________________________________ >> >> time-nuts mailing list -- [email protected] >> >> To unsubscribe, go to >> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> and follow the instructions there. >> >> >> >> >> > >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- [email protected] >> > To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
