| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage-controlled oscillator which can suppress variances of oscillation frequencies and improve phase noises, and to provide a communications device using the same. SOLUTION: A voltage-controlled oscillator 10 comprises a resonance circuit 11 and an amplifier circuit 2, and a resonance circuit 1 is connected to the amplifier circuit 2 with a coupling capacitor CO. The resonance circuit 11 comprises a variable capacitance diode VD11, inductors L11 to L13, and capacitors C11, C12, and a circuit for outputting a signal resonated by frequencies determined by an LC serial resonance circuit 12, which comprises the variable capacitance diode VD11 and the inductor L11 as a first inductor. The inductor L13 as a second inductor and an impedance element, in which impedance is high in a region near the oscillation frequency and impedance, is low in a low-frequency region is connected between the amplifier circuit 2 side of the inductor L11 and a ground.
|
