A Fork of a Different Tune
The Precisionist isn't Bulova's first venture into accurate electronic watches. Its Accutron mechanism, unveiled in 1960, used an electromagnetic tuning fork as its resonator. The mechanism, with a claimed variation of less than one minute per month, saw use in precision components on some of NASA's early satellites and spacecraft [source: Connor].
How the Precisionist Mechanism Works
At its heart, the Precisionist mechanism uses tried-and-true quartz crystal technology: A carefully measured electrical current energizes a quartz crystal shaped like a tuning fork, which begins to oscillate at a particular frequency. This vibration creates electrical pulses at a consistent rate; the watch's integrated circuits use those pulses to trigger the watch motor. The motor, in turn, moves the gears, and thus the hands, a tiny distance with each pulse. (To learn more about the process, check out our article on How Quartz Watches Work.)
This mechanism overcomes a number of the problems faced by manual and self-winding watches, most notably the dependence on a delicate balance of wheels and springs. These precise components can be affected by gravity and strong electromagnetic fields, and they lose accuracy if not regularly cleaned and tuned. But quartz watches aren't invincible; beyond the need to replace the battery over time, the mechanisms hinge on the integrity of a tiny quartz tuning fork. Change the fork's temperature or contaminate its surface with even a little dirt or dust, and its oscillating frequency can change, throwing off the entire system [source: DiFranco].
The Precisionist uses a pair of tech tricks to overcome the quartz mechanism's weak points. First, its crystal is unique: most quartz watches use crystals shaped into two-pronged tuning forks, but the Precisionist literally goes one better with a three-pronged fork that the company claims can oscillate at 262.144 kilohertz (or 16 beats per second), about eight times faster than the 32.768 kilohertz (about 1 to 2 beats per second) that is the typical frequency for quartz oscillators. For comparison, the balance wheels of most mechanical watches oscillate at frequencies of 8 to 10 beats per second. Like a microscope being able to show more detail at 100X magnification than at 20X, the higher-frequency oscillation means the watch's processor can measure smaller fractions of each second, giving it more precise data to translate into the hands' movement [sources: Lombardi; Arnstein].
Bulova engineers tackled the problem of temperature fluctuation by adding temperature regulation to the Precisionist's circuitry. The circuitry in the watch essentially senses temperature changes and adapts to corresponding changes in the quartz crystal's electric pulses. It's a small adjustment that might seem too miniscule to bother with, but tiny changes in pulse strength at the crystal's high oscillation frequency can add up to accuracy-killing deviations as the temperature changes [sources: Lombardi; DiFranco].