09 Aug 2017, 21:55
This was for fine-tuning the quartz crystal frequency to as nearly exactly 32.768KHz as possible. The guaranteed timekeeping accuracy was 60sec/year, or + or - 5 seconds a month. With this little gadget, you could make that adjustment in a few seconds. Quartz oscillators are very stable, but not absolutely stable (their frequency can drift gradually over time, even in a zero-temperature-change environment, due to "aging" effects in the crystal itself...the rate of drift diminishes gradually, and eventually can reach near-zero after a few years; this aging only happens when the crystal is actually under power). This is why Time Computer suggested you have the watch re-timed whenever the batteries were changed, to compensate for whatever frequency change had occurred since the watch left the factory (Time Computer allowed only a 1-week "burn-in" period, to weed out early failures, and watches that were drifting at unacceptably high rates).
Pulsar watches that were worn extensively (and, of course, are still working) are probably some of the most stable quartz oscillators on the planet, sensitive only to temperature changes (I have had working watches in my safe, that were off by only 10-12 seconds in a year...that's 0.3ppm accuracy...not bad for a 40-year-old piece of commercial electronics technology).
Last edited by
bruce wegmann on 11 Aug 2017, 10:12, edited 1 time in total.