| 摘要 |
PROBLEM TO BE SOLVED: To provide a VCO device, a tuner using the VCO device and a communication system with which both widening of the band of an output oscillation and noise reduction can be achieved. SOLUTION: The VCO device is provided with a plurality of variable capacitance diodes 40, 41 and 42 and a plurality of capacitors 30, 31 and 32 and until an output oscillation frequency is locked, all the control voltages of the variable capacitance diodes 40, 41 and 42 are varied. After the output oscillation frequency is locked, the variable capacitance diodes 41 and 42 are fixed at a control voltage in the case of lock and the control voltage of the variable capacitance diode 40 can be varied. COPYRIGHT: (C)2003,JPO
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