| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage controlled oscillator which obtains wide-ranging continuous oscillation frequencies by switching frequency ranges. SOLUTION: Capacities of capacitances C1 to C3 of fixed capacitors 41 to 43 for switching ranges of oscillation frequencies connected between a node N1 and a node N2 through MOSs 51 to 53 for a switch are set so that capacitance ratios C2/C1 and C3/C2 become a value of one or more and less than 2 (for example, 1.7), instead of powers of 2. Thereby, influence of parasitic capacitances of MOSs 51 to 53 in the OFF state is suppressed, frequency bands not covered when frequency ranges are switched are eliminated, and wide-ranging continuous oscillation frequencies are covered completely. COPYRIGHT: (C)2008,JPO&INPIT
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