[time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

Bob kb8tq kb8tq at n1k.org
Mon Apr 10 07:03:09 EDT 2017


Hi


> On Apr 9, 2017, at 10:01 PM, Alex Pummer <alex at pcscons.com> wrote:
> 
> actually it does not compensate for temperature it is just for reduce the production cost for the crystal. We --Jean Hoerni [founder of intersil, Eurosil and one of the  traitors who started Fairchild Semiconductor] and me -- made something very similar at the time of begin of the quartz clock era for Lipp a French watch maker in Bezancon [a city an France the spelling is most likely not correct]. The company exhibited it at the Basler exhibition of Horology, the clock was simple good working and not to expensive, Ebachos --OMEGA -- people visited the booth, they also had their quartz  clock which was much more expensive -- they looked, the Lipp clock and told na there are Rolls-Royce s and deux chevaux [that was a simple little ugly but very reliably French car ] as response Mr. Hoerni told them yes, and there are technologies not known in your house, the Omega people recognized him and walked away quietly...
> 
> 73
> 
> Alex

Just to put this in context. The “prior state of the art” was to have a trimmer capacitor in the watch (or clock) module to set it on 
frequency. That’s why it was obvious from a quick look that something was different. There were semiconductor companies making
watch modules at the same time still using trimmer capacitors. The pulse drop / add was not at all an “obvious” solution at the time. 

Bob


> 
> 
> On 4/9/2017 1:11 PM, Bill Hawkins wrote:
>> Nice article in Wikipedia. Didn't see any familiar names in the
>> reference list, though.
>> 
>> Seems to me inhibition compensation is useful for compensating for the
>> variation in purchased crystal frequencies, but not for temperature
>> compensation.
>> 
>> Also seems to me that a watch spends 2/3 of a day at wrist temperature
>> and 1/3 at bedroom temperature, which varies with the seasons.
>> 
>> Would a ceramic capacitor crafted for a certain temperature coefficient
>> work? Can the fork have a crafted tempco?
>> 
>> Bill Hawkins
>> 
>> 
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Ron
>> Bean
>> Sent: Sunday, April 09, 2017 12:05 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork
>> crystal specs
>> 
>>> In your case, the car sits in an environment that matches their test
>>> setup well. In my case ?\200? not so much.
>> FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I
>> don't remember when I bought it (I moved it from my previous car).
>> 
>> I assume that all quartz clocks and watches these days use "inhibition
>> conpensation".
>> 
>> https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation
>> 
>> 
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