Breitling COCKPIT B50 Mode D'emploi page 112

WEEK NUMBER
choice of standard used to indicate the week number
WEEK XX
week number
XXDAyS
number of days set in CDCUCLK and ALCU functions
YOUR BREITLING CHRONOMETER
A chronometer is a high-precision instrument that has successfully passed the
entire battery of tests imposed by the COSC (Swiss Official Chronometer Testing
Institute), a neutral and independent body which individually tests each move-
ment according to the prescriptions in force.
The certification test for wristwatch chronographs with quartz oscillators consists
in observing each movement for 13 days and 13 nights, in several positions and at
3 different temperatures (8ºC, 23ºC, 38ºC). To earn the prestigious chronometer
label, a movement's performances must meet 6 very strict criteria, including a daily
variation in rate of within ±0.07 seconds, corresponding to an annual precision
of ±25 seconds. The variation in rate of the SuperQuartz™ caliber fitted in your
Breitling watch far and above exceeds these demands, achieving a rate of ±15
seconds a year.
The term "chronometer" should not be confused with that of "chronograph",
which is a complicated watch fitted with an additional mechanism enabling the
measurement of the duration of an event. A chronograph is not necessarily chro-
nometer-certified, but all Breitling chronographs carry the much-coveted title of
"chronometers".
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