NavList:

   

Reply

Dov-
 This (correcting a quartz count) was implemented around 1980 in a totally 
sealed diving watch which I think came out under the name "Pulsar" before the 
new company of that name. It was a hermetically sealed watch, solar cells for 
the 'face' and an LED display on the 'shoulder' of the face. Besides the time 
set buttons it also offered a calibration/adjustment mode, since there was no 
way to open the watch for internal adjustment.
 Since then watch accuracy has improved, typically better than +-15 seconds a 
month which is well beyond what the mass market pays atttention to. I don't 
see any market incentive for a manufacturer to do better, unless you buy the 
Casio GPS watch which will put the accuracy of 16 atomic clocks on your 
wrist--without your need to manually adjust it.

 I've been told the radio watches use a power conservation algorithm. They 
only turn on the receiver circuit near midnight (when the WWV signal should 
be propogating, etc. at its best) and try to correct themselves once every 24 
hours. If they miss the correction, then they become more agressive about 
turning on and seeking it. This may vary with manufacturers of course...but 
in any case the watch would only need to see "sky" once daily, since the 
typical quartz accuracy of +-15 sec/month means it will still be within 1/2 
second of "right" for the rest of the day.

   

Reply