With the CMOS logic used in watches, the big power hog is due to charging and discharging the gate capacitance of the various logic gates. The faster you charge and discharge the gate's, the more power you loose due to I2R losses, and E-M radiation.
Thankfully, the high capacity lithium cells available today provide lots more uA-hours than the older silver-oxide cells of yor, so it is possible for the energy budget on a premium electronic watch to be higher than was previously acceptable. I would think that most watch manufacturers would take that extra power budget, and use it to extend the time between cell changes, and to spin more fancy dial motors. It is not clear to me that a 32KHz xtal is any less stable than a 262KHz xtal, though. I would think there would be a lot more to be gained by using a microprocessor/thermistor to measure the temperature within the watch, and provide an adjustment to compensate for the xtal's natural temperature sensitivity. -Chuck Harris Perry Sandeen wrote:
List, 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? Regards, Perrier
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