TIMEPIECE DEVICE AND METHOD OF OPERATION THEREOF
A timepiece device includes a control unit for time keeping, which is synchronizable by a clock generator. The timepiece device has at least two crystal oscillators built respectively by at least one crystal unit, whereby a first crystal oscillator with a first crystal unit and with a predetermined nominal oscillation frequency is suitable for use as the clock generator of the control unit during a vehicle standby mode, and whereby the oscillation frequency of the first crystal oscillator is at least temporarily measured and adjustable by a second crystal oscillator with a second crystal unit whose nominal oscillation frequency is higher than that of the first crystal oscillator. In a method of operation of the timepiece device, the oscillation frequency of the second crystal oscillator is compensated against the temperature by the software inside the control unit.
1 . A timepiece device, comprising:
a clock generator; and
a control unit for timekeeping, which is synchronizable by the clock generator,
wherein the clock generator includes at least two crystal oscillators built respectively by at least one crystal unit, wherein a first crystal oscillator with a first crystal unit and with a predetermined nominal oscillation frequency is suitable for use as the clock generator of the control unit during a vehicle standby mode, and the oscillation frequency of the first crystal oscillator is at least temporarily measured and adjustable by a second crystal oscillator with a second crystal unit whose nominal oscillation frequency is higher than that of the first crystal oscillator.
2 . The timepiece device according to claim 1 , wherein the nominal oscillation frequency of the first crystal oscillator is below 0.1 MHz.
3 . The timepiece device according to claim 1 , wherein the first crystal unit is a tuning fork crystal unit.
4 . The timepiece device according to claim 1 , wherein the nominal oscillation frequency of the second crystal oscillator is higher than 0.5 MHz.
5 . The timepiece device according to claim 1 , wherein the second crystal unit is an AT-cut crystal unit.
6 . The timepiece device according to claim 1 , wherein a temperature-dependent frequency deviation of the second crystal oscillator is lower than that of the first crystal oscillator.
7 . A method of operation of a timepiece device comprising a control unit for time keeping, which is synchronized by a clock generator, the method comprising:
measuring and adjusting a nominal oscillation frequency of a first crystal oscillator at least temporarily in a vehicle standby mode by a second crystal oscillator whose nominal oscillation frequency is higher than that of the first crystal oscillator.
8 . The method according to claim 7 , further comprising measuring an operating temperature of a second crystal unit of the second crystal oscillator in predetermined time periods.
9 . The method according to claim 8 , further comprising performing, as a function of the measured operating temperature of the second crystal unit, a periodic temperature compensation of the second crystal unit.