Temperature compensating circuit
AssigneeKabushiki Kaisha Daini Seikosha
InventorTsuneo Kuwabara
Life of this patent
Estimating the term…
Abstract
Temperature compensating circuit for an electronic timepiece having two piezo electric resonators having different frequency-temperature characteristics. Two piezo electric resonators are a major resonator having smaller frequency variation rate in temperature variation and a subsidiary resonator having larger frequency variation rate in temperature variation. And also the temperature compensating circuit includes a variable counter for counting the output signal of the major oscillator having the major resonator, a gate time setting circuit controlled by both the outputs of subsidiary and the variable counter, and a counter for counting the output signal of the major oscillator. As a result, the temperature compensating circuit is able to improve the accuracy of the timepiece.
Claims1
A temperature compensating circuit comprising:
- two piezo electric resonators having different frequency-temperature characteristics, a major resonator having smaller frequency variation rate in temperature variation and a subsidiary resonator having larger frequency variation rate in temperature variation;
- an oscillator for oscillating said two resonators independently;
- a gate time setting circuit for setting a gate time using one of outputs of said oscillator;
- a counter for counting the other output of the oscillator by a gate time set by the gate time setting circuit;
- an operation circuit for operating an oscillation frequency of the resonator using coefficients of each term of high degree polynominal approximately concluded when a counting value is a variable against an oscillating frequency of the major resonator;
- a counter for counting the oscillator output of the major resonator;
- and a comparator for comparing the counting value of the counter with the counting value of the operation circuit and for generating a reset signal when the counting values coincide with each other.
Dependencies are inferred from the claim text.