Importance

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Abstract

A temperature-compensated oscillator circuit utilizes a quartz oscillator for producing an oscillating signal having a variable oscillator frequency which fluctuates in response to ambient temperature change. A variable semiconductor capacitor having a variable capacitance is connected to the quartz oscillator for regulating the oscillating frequency thereof according to the variable capacitance. The variable semiconductor capacitor comprises a semiconductor substrate, a floating electrode disposed on and electrically insulated from the semiconductor substrate, an injection electrode formed in the semiconductor substrate for injecting a given amount of electric charge into the floating electrode to set the value of the variable capacitance, and a capacitance electrode formed in the semiconductor substrate and receptive of a bias voltage effective to adjust the set value of the variable capacitance. A control circuit detects ambient temperature change and produces a bias voltage according to the detected ambient temperature change and applies the bias voltage to the variable semiconductor capacitor to thereby enable the same to compensate the oscillating frequency for the temperature change.

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First Claim