[time-nuts] New precision watch
bell.peter at gmail.com
Mon Dec 19 06:59:41 EST 2011
I think the Grand Seikos are specified at the same +/- 10 seconds a
year accuracy as that Bulova. They use a slightly different approach
though - it's a standard 32768 Hz xtal, but its thermally compensated.
I don't know of any other watches that use a 262144 Hz xtal on its
own, but there were some designs that used both a 32768 and 262244 Hz
xtals and used the tracking between them for temperature compensation
(I think this was used in some Seiko and ETA watches). The Bulova
certainly has a great price for a watch of that spec.
I don't know of any watches that used an oscillator as high as 10 MHz
- the highest clock I ever heard of in a watch was in a very limited
edition Citizen that ran at 4 MHz, and which was specced at +/- 3
seconds a year without thermal compensation. Omega also made a
high-frequency watch that I think ran at 2.4 MHz and had a +/- 5
seconds / year accuracy spec. Both of these used AT-cut xtals and
suffered from rather poor battery life (about 1 year).
On Mon, Dec 19, 2011 at 1:47 PM, Perry Sandeen <sandeenpa at yahoo.com> wrote:
> I saw an ad today for a Bulova Champlain Precisionist watch. It is supposed to be accurate to + 10 seconds a year. What stood out in the as is that they are using a 262,144 KHz crystal eight times the frequency commonly used.
> I don’t know if it is more accurate than the Seiko (?) discussed on the list about a year ago, but it seems to be about USD $2,100 cheaper. Around USD $600 or less depending on the model. Is a 10 MHz or so crystal on the horizon?
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