| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage-controlled crystal oscillator that facilitates the design and manufacturing of a circuit easily coping with a low operating voltage tendency and including a desirable variable frequency range and a desirable variable frequency characteristic. SOLUTION: A variable reactance circuit 7 including a FET as an amplifier element and reactance elements Z1, Z2 and the reactance of which viewed from an output terminal is made variable by a control voltage VC is provided in series with a crystal vibrator 2 inserted in a feedback loop of an oscillation circuit 1, and the desirable variable frequency characteristic and the desirable variable frequency range are attained for the oscillating frequency by revising the combination of the reactance elements and the circuit constant. A configuration of employing a resistor for one of the reactance elements Z1, Z2 and a capacitor for the other, a configuration of series connection of a resistor and a capacitor or a configuration of parallel connection of a resistor and a capacitor for both the elements is adopted. COPYRIGHT: (C)2007,JPO&INPIT
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