Patent ID: 8482356

Claim:
A constant-temperature piezoelectric oscillator comprising: a piezoelectric vibrator; an oscillation circuit adapted to excite the piezoelectric vibrator; a frequency voltage control circuit adapted to control an oscillation frequency in accordance with a voltage; a temperature control section adapted to control the temperature of the piezoelectric vibrator; and an arithmetic circuit adapted to process information input and supply the frequency voltage control circuit with a signal, wherein the temperature control section includes a temperature-sensitive element adapted to sense the temperature, a heating element adapted to heat the piezoelectric vibrator, and a temperature control circuit adapted to control the temperature of the heating element based on a temperature signal of the temperature-sensitive element, the frequency voltage control circuit includes a voltage-controlled capacitance circuit capable of controlling a capacitor in which a capacitance value is varied in accordance with the voltage, and a compensation voltage generation circuit, the arithmetic circuit makes the compensation voltage generation circuit generate the voltage for compensating a frequency deviation due to a temperature difference between zero temperature coefficient temperature Tp of the piezoelectric vibrator and setting temperature Tov of the temperature control section based on a frequency-temperature characteristic compensation amount approximate formula adapted to compensate the frequency deviation, the frequency-temperature characteristic compensation amount approximate formula is obtained based on frequency-temperature characteristics data of a plurality of constant-temperature piezoelectric oscillators, and the capacitor is connected to the piezoelectric vibrator in series.