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

[Bob kb8tq]

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 ….

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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