| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage controlled oscillator that can stably oscillate an oscillation signal while satisfying an optimum oscillating condition for each of frequency bands and can adjust the oscillating frequency at nearly the same sensitivity by changing a frequency shift voltage over the frequency bands. SOLUTION: The multi-band voltage controlled oscillator has a plurality of resonance circuits (110, 120) each having a prescribed resonance frequency, a resonance circuit section (100) that can shift a resonance frequency within the respective frequency bands with a frequency shift voltage applied to a 1st control terminal (103), and an oscillation circuit section (200) having a transistor(TR) (T1) whose base is connected to an output terminal (101) to which the plurality of resonance circuits are connected. The emitter-collector capacitance of the TR T1 is changed by a frequency band selecting voltage applied to a 2nd control terminal (201) to satisfy the optimum oscillating condition for each of the plurality of resonance frequencies.
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