The invention relates to a method for producing a reference frequency f. According to the invention, the use of a first optical resonator (3a; 24) and of a second optical resonator (25) is provided, wherein the first resonator (3a; 24) has a first resonator mode having a first frequency f1 and the second resonator (25) has a second resonator mode having a second frequency f2, wherein the frequencies of the two resonator modes are functions of an operating parameter BP and assume the values f1 and f2at a specified value BP.sub.0 of the operating parameter such that f1(BP.sub.0)=f1 and f2(BP.sub.0)=f2 apply, wherein the resonators (3a; 24, 25) are designed in such a way that the respective first derivatives of the frequencies f1(BP), f2BP) with respect to BP or at least respective difference quotients around BP.sub.0 correspond within a deviation of at most 0.1%, wherein light of the first frequency f1 is stabilized to the first frequency f1 by means of the first resonator and light of the second frequency f2 is stabilized to the second frequency f2 by means of the second resonator, and wherein the difference between the stabilized frequencies f1 and f2, f=|f1f2|, is determined in order to obtain the stabilized reference frequency f.

The invention relates to a method for producing a reference frequency f. According to the invention, the use of a first optical resonator (3a; 24) and of a second optical resonator (25) is provided, wherein the first resonator (3a; 24) has a first resonator mode having a first frequency f1 and the second resonator (25) has a second resonator mode having a second frequency f2, wherein the frequencies of the two resonator modes are functions of an operating parameter BP and assume the values f1 and f2at a specified value BP.sub.0 of the operating parameter such that f1(BP.sub.0)=f1 and f2(BP.sub.0)=f2 apply, wherein the resonators (3a; 24, 25) are designed in such a way that the respective first derivatives of the frequencies f1(BP), f2BP) with respect to BP or at least respective difference quotients around BP.sub.0 correspond within a deviation of at most 0.1%, wherein light of the first frequency f1 is stabilized to the first frequency f1 by means of the first resonator and light of the second frequency f2 is stabilized to the second frequency f2 by means of the second resonator, and wherein the difference between the stabilized frequencies f1 and f2, f=|f1f2|, is determined in order to obtain the stabilized reference frequency f.

A positioning apparatus includes the following. A first oscillator outputs a clock signal. A second oscillator outputs a clock signal which is more accurate than the first oscillator. A receiver receives a radio wave from a positioning satellite. A positioning controller calculates a present position based on positioning information calculated from the received radio wave. The positioning controller controls switching of a supply source of the clock signal supplied to the receiver and the positioning controller between the first oscillator and the second oscillator depending on a reception status of the radio wave from the positioning satellite by the receiver.

A positioning apparatus includes the following. A first oscillator outputs a clock signal. A second oscillator outputs a clock signal which is more accurate than the first oscillator. A receiver receives a radio wave from a positioning satellite. A positioning controller calculates a present position based on positioning information calculated from the received radio wave. The positioning controller controls switching of a supply source of the clock signal supplied to the receiver and the positioning controller between the first oscillator and the second oscillator depending on a reception status of the radio wave from the positioning satellite by the receiver.

The method for test the rate of an electronic watch with a time base device (1) comprises three main steps for the test on test equipment. The time base device comprises at least one watch module (2) with a resonator (3) connected to an oscillator of an electronic circuit (4), which is followed by a divider circuit, which is controlled by an inhibition circuit, and which provides a divided timing signal for a motor. In a first step, a measurement is made of the frequency of the oscillator reference signal in at least one measurement period without inhibition. A second step is provided for acquiring the current inhibition value to inhibit a certain number of clock pulses in a subsequently inhibition period and to determine the inhibition value. Finally, a third step is provided for calculating the corresponding rate frequency of the watch.

The method for test the rate of an electronic watch with a time base device (1) comprises three main steps for the test on test equipment. The time base device comprises at least one watch module (2) with a resonator (3) connected to an oscillator of an electronic circuit (4), which is followed by a divider circuit, which is controlled by an inhibition circuit, and which provides a divided timing signal for a motor. In a first step, a measurement is made of the frequency of the oscillator reference signal in at least one measurement period without inhibition. A second step is provided for acquiring the current inhibition value to inhibit a certain number of clock pulses in a subsequently inhibition period and to determine the inhibition value. Finally, a third step is provided for calculating the corresponding rate frequency of the watch.

An electronic module including at least one electric motor for driving an analog display, a clock module including a time base delivering a clock signal connected to a divider circuit, the divider circuit delivering a reference signal sent to a control circuit arranged to control the electric motor, the clock module further including a measuring and correction circuit arranged between the time base and the divider circuit and delivering an intermediate compensated signal. The time base, the compensation module, the divider circuit, and the control circuit are arranged in a same case to form the clock module.

An electronic module including at least one electric motor for driving an analog display, a clock module including a time base delivering a clock signal connected to a divider circuit, the divider circuit delivering a reference signal sent to a control circuit arranged to control the electric motor, the clock module further including a measuring and correction circuit arranged between the time base and the divider circuit and delivering an intermediate compensated signal. The time base, the compensation module, the divider circuit, and the control circuit are arranged in a same case to form the clock module.

A temperature-compensating clock frequency monitor circuit may be provided to detect a clock pulse frequency in an electronic device that may cause erratic or dangerous operation of the device, as a function of an operating temperature of the device. The temperature-compensating clock frequency monitor circuit include a temperature sensor configured to measure a temperature associated with an electronic device, a clock having an operating frequency, and a frequency monitoring system. The frequency monitoring system may be configured to determine the operating frequency of the clock, and based at least on (a) the operating frequency of the clock and (b) the measured temperature associated with the electronic device, generate a corrective action signal to initiate a corrective action associated with the electronic device or a related device. The temperature sensor, clock, and frequency monitoring system may, for example, be provided on a microcontroller.

A compensation circuit for an oven-controlled crystal oscillator serving as a reference for a phase-locked loop in holdover mode is disclosed. A non-linear function module generates a modified aging signal that is a non-linear function of an aging signal. A first Kalman filter generates an estimate of the frequency drift of the crystal oscillator based on the temperature signal. A second Kalman filter generates an estimate of the frequency drift based on the modified aging signal. A combining and comparing module combines the estimates generated by the first and second Kalman filters and compares the estimates with detected frequency drift to produce an error signal to update the Kalman filters. In holdover mode the Kalman filters generate an error signal to correct the oscillator frequency based on updates obtained during operation of the phase-locked loop in normal mode.