[time-nuts] 4.19 MHz xtal

Sun Mar 31 22:31:56 UTC 2019

Easy. 2^22 is 4194304. This means that a crystal of that frequency connected to a chain of 22 flip-flops will produce one pulse per second. More modern Quartz clocks are based on 32768Hz crystals which is 2^15Hz. The reason for the change is that such low frequency crystals require a tuning-fork type construction that until recently was not as easy to produce accurately as an AT cut crystal, but AT cut crystals only work down to about 1MHz.

Matthew 

Sent from Matthew D'Asaro's iPhone

> On Mar 31, 2019, at 2:29 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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