[time-nuts] Question on crystal jumps
quenbob5 at pacbell.net
Thu Oct 23 01:22:18 UTC 2008
Do rubidium standards use an OCXO?
----- Original Message -----
From: "Rick Karlquist" <richard at karlquist.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
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
> iovane\@inwind\.it 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
>> Thanks in advance.
>> Antonio I8IOV
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