[time-nuts] 4.19 MHz xtal

[Bob kb8tq]

Hi

Simple answer is that it likely is an AT cut crystal. You can get a 1 ppm-ish sort of stability over
0 to 50 C out of an AT. The 32 KHz crystal you sort of expect to see likely has a couple hundred 
ppm-ish stability over the same temperature range. 

32 KHz crystal have been the norm in “quartz” watches and clocks pretty much from their modern 
origin in the early 1970’s. Before that crystal based clocks did exist, but not using the same sort of 
low power / small size / low cost approach we now accept as the norm. You can fine “precision crystal
based clocks” going back at least into the 1930’s. They just didn’t do it the same way. 

Bob

> On Mar 31, 2019, at 5:29 PM, Neville Michie <namichie at gmail.com> wrote:
> 
> Hi,
> I have a Philips quartz clock that runs on 4.19 MHz.
> In spite of the high frequency it still runs for years
> on a C cell.
> Can any of the quartz crystal gurus explain why this 
> frequency was chosen? I believe that this clock was 
> supposed to have better than usual accuracy.
> Philips always had a high level of engineering excellence.
> 
> cheers, 
> Neville Michie
> 
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