Temperature-compensated crystal oscillator and method of temperature compensation

摘要

This temperature-compensated crystal oscillator includes: a temperature sensor 11; an analog type temperature compensating section 12; a digital type temperature compensating section 13; an adder circuit 14; and a voltage controlled crystal oscillating circuit 3. The analog type temperature compensating section 12 and the digital type temperature compensating section 13 each generate temperature compensation voltages based on an input voltage corresponding to the temperature detected by the temperature sensor 11. Both of these temperature compensation voltages are added to each other by the adder circuit 14 and the resultant added voltage is applied to a voltage control terminal of the voltage-controlled crystal oscillating circuit 3. Thereby, an oscillation frequency of the voltage-controlled crystal oscillating circuit 3 is stabilized, resulting in realization of the temperature compensation of a crystal resonator 4.