| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency synthesizer integrated at a low cost having a wide variable frequency range and good phase-noise characteristics. SOLUTION: A VCO composed of a resonance tank circuit (A) and an amplifier circuit (B) oscillating at a resonance frequency of the tank circuit (A). The resonance circuit (A) comprises a capacity-band switching circuit (D) for varying the oscillation frequency band, and a current-band switching circuit (E) for feeding the amplifier circuit (B) with an optimum current corresponding to each oscillation frequency band, resulting in increasing the variable range of oscillation frequency and providing a satisfactory broadband phase noise characteristics by optimizing the current at each frequency band. COPYRIGHT: (C)2006,JPO&NCIPI
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