My bet would be flicker and divide by 120. Doesn't really matter. But since these watches use the light to charge the battery, sensing the frequency is a byproduct. Nice and simple.
On Wed, Apr 20, 2011 at 10:10 AM, jmfranke <[email protected]> wrote: > Do they detect the light flicker or the ambient ac field. Light flicker is > 120 Hz. > > Very interesting, > > John WA4WDL > > -------------------------------------------------- > From: "tom jones" <[email protected]> > Sent: Wednesday, April 20, 2011 9:43 AM > To: <[email protected]> > Subject: [time-nuts] 60hz disciplined watch > > Most if not all Citizen ecodrive watches are disciplined by 60hz light >> flicker that average >> the 60hz light flicker over approximately 10 days before a rate adjustment >> is preformed. >> >> I have four citizen ecodrives; >> >> Plain jane quartz analogue ecodrive with mechanical calendar that is 60hz >> disciplined. >> >> Stainless steel skyhawk ecodrive ana-digital that is 60hz disciplined. >> I've monitored this one >> for over a week it was holding 13 miliseconds for over a weeks duration >> (off the wrist mode) compaired to my cesium and ribidium references and got >> distracted from futher measurements of this citizen skyhawk as I was >> consumed with other measurements and comparisons between loran gps cesium >> ribidium and other watches. >> >> Blue angles citizen skyhawk ana-digital that half the time seems to be >> 60hz disciplined and other times unsure. >> This blue angles citizen skyhawk has the same movement as the stainless >> steel skyhawk which is definately 60hz disciplined. >> I suspect this blue angles skyhawk that I purchased out of the country >> could have 50hz and 60hz dicipline modes? >> >> My fourth citizen ecodrive is the stars & stripes forever yacht timer >> ana-digital which is 60hz diciplined. >> This watch reboots every feb 28th at midnight to utc time zones and jan 1 >> 2004 (not sure of the exact year is crashes to) some kind of leap year bug! >> >> Only unexpected temperature changes experienced by the ecodrive citizen >> watches produce significant error >> (.5 to 1 second over several days of temperature varation) there rate will >> correct after an approximate 10 day time constant. >> >> Many wrist watch forums make reference to citizen ecodrive rate accuratces >> remarking that citizen uses some propriatary rate techniques. It's simply >> 60hz light flicker received at the ecodrives solarbattery/photocell. >> >> I would recomend when setting your citizen ecodrive watches to set them >> 2.5 to 3 seconds fast if worn continous because that is approximately how >> much time will be lost before its rate gets compensated the first time. >> >> A Great Day to All , Tom >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
