| 摘要 |
A multi-band type voltage controlled oscillator has a resonant circuit part (100) and an oscillating circuit part (200). The resonant circuit part (100) has plural resonant circuits (110, 120) having their resonant frequencies, and controls the plural resonant frequencies in their respective frequency-bands by a frequency control voltage to be applied to a first controlling terminal (103). The oscillating circuit part (200) has a transistor (T1) of which the base is connected to an output terminal (101) to which the plural resonant circuits (110, 120) are coupled. By changing the capacitance between the emitter and collector of the transistor (T1) with a frequency band selective voltage to be applied to a second controlling terminal (201), an optimum oscillating condition is satisfied at each of the plural resonant frequencies. <IMAGE> |
