| 摘要 |
A VCO include a resonance tank circuit(A) and an amplification circuit(B) which oscillates and is amplified at a resonance frequency of the resonance tank circuit(A). The resonance tank circuit(A) is provided with a capacity band switching circuit(D) for varying an oscillation frequency band, and a current band switching circuit(E) for feeding an appropriate current, corresponding to each oscillation frequency band, to the amplification circuit(B). This allows expansion of the oscillation frequency variable range as well as realization of a favorable phase noise characteristic in a broad band by optimization of a current in each frequency band. |
