Patent ID: 6737928
Filing Date: 2004-05-18
Classification: H03L

Abstract:
A temperature-compensated crystal oscillator comprising:a crystal unit having frequency vs. temperature characteristics; a voltage-variable capacitive element inserted in a closed oscillating loop including said crystal unit; an amplifier for keeping oscillation in said closed oscillation loop; means for applying a temperature compensating voltage to an anode of said voltage-variable capacitive element; and means for applying a voltage to prevent a current from flowing through said voltage-variable capacitive element to a cathode of said voltage-variable capacitive element; whereby said frequency vs. temperature characteristics can be compensated for by the temperature compensating voltage applied to the anode of said voltage-variable capacitive element, said temperature compensating voltage being generated by a voltage source different from at least one voltage source generating said voltage to prevent a current from flowing through said voltage-variable capacitive element.