I have a Citizen A660 movement which was spec’d at +/- 5 secs per year. I monitored it from when I bought it in December 2010 until its battery failed on 03/11/2012. It was in spec when both on and off the wrist (off the wrist it was in a drawer at a constant temperature and the accuracy was a stability was lower) . The error in the first 18 months gave a yearly rate of +1,2 secs. Not bad. So maybe the new movement is just getting the advantage of higher frequency so that their cycle hops are finer grained.
> Le 11 avr. 2018 à 22:24, Bob kb8tq <kb...@n1k.org> a écrit : > > Hi > > Guess at the aging > > Cut the crystal so it’s fairly flat at 25 to 35C > > Do a basic / simple temperature compensation (TCXO) > > …. and count on the errors to average out. > > The success of all that will depend a lot on how close your wrist is to the > environment they used for their guesswork. Did they count on you taking > the watch off at night or not? What temperature is the room at? ….. > > Before you say it can’t be done, the whole “average out” thing is how time > pieces have been done for hundreds of years. The device may swing this > way and that …. done properly it eventually averages out. How well it works > for you … that depends. > > Bob > >> On Apr 11, 2018, at 12:26 PM, tn...@joshreply.com wrote: >> >> That comes out to about 30ppb, and this is a pocket watch so they dont seem >> to depend on the temp stabilization of being attached to a human wrist. >> >> >> >> https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco >> -Drive-Movement-04.jpg >> >> >> >> Ive been reading about the new watch that contains this crystal for about a >> month, but just saw some more detail today >> >> >> --- >> >> AT-CUT QUARTZ CRYSTAL OSCILLATOR >> >> While AT-cut quartz crystals have indeed been in production and use since as >> early as 1934, the technology is more common in larger applications and not >> necessarily wristwatches. To address the needs of individuals seeking only >> the most accurate performance in a wristwatch, Citizen sought to apply and >> optimize this available technology in a way that could serve watch consumers >> on a more direct and personal level. When working to reach the accuracy of >> the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a >> more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut >> variations allow for greater temperature tolerances, specifically in the >> range of -40°C to +125°C. Additionally, this configuration allows for >> reduced deviations caused by wearer orientation, which can cause significant >> changes in accuracy that aren't negligible when attempting this kind of >> performance. As a result, wearers will not have to worry about errors caused >> by spatial orientation and positioning becomes less of a concern. The same >> can be said about durability, which Citizen also improved upon in >> conjunction with the AT-cut oscillator. After all, shock experienced in >> day-to-day situations could easily prove detrimental even for quartz >> movements. And when the goal is an annual accuracy of ±1 second, that just >> isn't acceptable. >> >> >> >> https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/ >> >> --- >> >> >> >> Is this possible with an MXCO running across this wide temp range? How are >> they compensating for aging at this level of precision? >> >> >> >> Thanks! >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. Don’t worry about how powerful the machines are. Worry about who the machines are giving power to. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.