[time-nuts] Question on crystal jumps
Max Robinson
max at maxsmusicplace.com
Thu Oct 23 01:31:57 UTC 2008
This is a very interesting thread. When I retired from Western Kentucky
University in 2001 I was given a very expensive mantel clock. Seven day
wind up with a balance wheel. I have had a lot of fun regulating it over
the last 7 years. Right now I have it holding within 5 seconds a month but
past experience has shown that it won't hold indefinitely. Since the
balance wheel is also an oscillator I assume it will undergo these frequency
jumps.
Regards.
Max. K 4 O D S.
Email: max at maxsmusicplace.com
Transistor site http://www.funwithtransistors.net
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----- Original Message -----
From: "Bob Q" <quenbob5 at pacbell.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Wednesday, October 22, 2008 8:22 PM
Subject: Re: [time-nuts] Question on crystal jumps
> Do rubidium standards use an OCXO?
> Bob Q.
>
> ----- 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
>>> speculation.
>>>
>>> Thanks in advance.
>>> Antonio I8IOV
>>>
>>>
>>>
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>>
>>
>>
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