Ebauches S.a.

Fernand Chetelat

Pierre Hersberger

Daniel Rochat

Igor Scherrer

An internal correction circuit is provided to correct the timepiece error caused by the crystal oscillator frequency changes. The timepiece operates by frequency dividing the oscillator frequency to obtain a predetermined operating frequency. The correction circuit is operated by the user on any initialization point, such as the start of any minute from a reference time source to generate a first input signal. The user at any following minute of the reference time source generates a second input signal. The correction circuit counts a first and second number of time units of different lengths between the first and second input signals. The circuit then forms a division ratio from the first and second numbers. That ratio is used to change the frequency divider division ratio to adjust the watch for the crystal frequency error just calculated.

Electronic timepiece having an adjustable rate of division and method

The chronograph comprises a device allowing to memorize at least two lapses of time and a subtraction device to effect the absolute difference between two lapses of time or time intervals which are memorized and preselected. The subtraction device includes:

Electronic chronograph

An electronic watch having an alpha-numeric display for displaying the time in seconds, minutes and hours and the date and day of the week. The date and day of the week is displayed in an abbreviated form and the language used for the display can be optionally selected without modification of the circuit by appropriate connection of a control terminal.

Electronic watch

It is known that an electro-luminescent display increases its light emitting efficiency with the current through it. Such a display in a watch run from a small battery, is fed by short impulses of high-intensity current by means of discharges from two capacitors which are alternately charged and discharged by transistor switches opened and closed by externally supplied impulses. The battery current is thus kept substantially constant and low. A series of digits or segments thereof, if used, may be fed in sequence with the impulses.

Device in a time piece for feeding an electro-luminescent display

A device for correcting running of an electronic watch comprises two contactors acting on respective bistable circuits in turn acting on a combinatory circuit controlling a counter which provides binary correction information to an inhibitor circuit. The latter is arranged to inhibit a number of pulses of a pulse generator having a predetermined nominal frequency above a given value, to set the frequency at said given value prior to division to provide accurate clock pulses fed to a device for indicating the time. Successive actuation of respective contactors corresponds to increasing or decreasing the number of inhibited pulses from an approximate number stored in a programmable memory.

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Cortaillod, Switzerland

Fernand Chetelat