[time-nuts] Re: Do crystals still jump?

[Bill Beam]

I would be surprised to find a crystal that did not jump at some level.
Remember that a crystal in use is undergoing continuous stress and strain.
Any small defect in the crystal structure could be changed resulting in a
small change in physical dimension thus changing its resonant frequency.
Thump on any rock hard enough and it will change shape.

Bill, NL7F

On Sun, 4 Sep 2022 08:17:55 -0800, Bob kb8tq via time-nuts wrote:

>Hi

>There are a number of very different types of jumps. It depends
>a lot on just which sort you are worried about. Hysteresis typically
>comes in looking very different than a jump. Temperature driven
>jumps can occur for a number of reasons G��.

>Bob

>> On Sep 3, 2022, at 5:11 PM, glenlist via time-nuts <time-nuts at lists.febo.com> wrote:
>> 
>> wow. Great story Detlef.
>> 
>> I have had crystals 'jump' but this was at the part per billion level... mainly hysteresis effects. It causes my pulling loop to go mad. There 
might have also been some non monotonic behaviour also.
>> 
>> I was told by the crystal mfr (this about about 30 yrs ago) the better crystals exhibited lower hysteresis, but it was present in all crystals 
to some degree. .
>> 
>> 
>> On 4/09/2022 6:26 am, dschuecker via time-nuts wrote:
>>> Hi,
>>> 
>>> yes, they do jump.
>>> 
>>> Some years ago our DSL-modems fell out of sync when they were exposed to a temperature jump., ie. in the warm exhaust of a vac 
cleaner. Sure, all xtals have a temperature dependency, but with this batch of crystals there was a frequency change of 50ppm or so for a 
temp change of 2Kelvin. These are perceived numbers, I do not have exact data. The modems' PLL could not track the frequency change 
fast enough and the modem fell outta sync. . We had a lot of these crystals in the field and that was a pretty severe problem.
>>> 
>>> Cheers
>>> 
>>> Detlef
>>> 
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Bill Beam
NL7F