| 摘要 |
A plurality of voltage controlled oscillators and a plurality of dividers are provided corresponding to a plurality of frequency bands, respectively, and a phase comparator, a charge pump, and a low pass filter are used in common for the plurality of frequency bands. A switch which selects any one of the plurality of voltage controlled oscillators, and a switch which selects any one of the plurality of dividers are provided. A controller which performs a gain control of a frequency synthesizer loop is further provided so that a gain characteristic of the frequency synthesizer loop comprised of a selected voltage controlled oscillator, selected divider, phase comparator, charge pump, and low pass filter becomes constant regardless of a selection change of the plurality of voltage controlled oscillators and the plurality of dividers.
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