FREQUENCY SYNTHESIZER, WIRELESS COMMUNICATION APPARATUS AND CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a frequency synthesizer in which control sensitivity or modulation sensitivity is not affected by the fluctuation of manufacturing tolerance and temperature or power supply voltage or the like while securing the conventional frequency correction function.

SOLUTION: A plurality of control voltages V1 to V3 are applied to a VCO 5 in order and operation for respectively calculating operation reference voltages Vref1 to Vref3 of variable capacitance elements VC51 to VC56 is performed so that a difference between an oscillation frequency and a target frequency of the VCO 5 may be minimum about each control voltage. By the operation, the frequency synthesizer can set not only the oscillation frequency of the VCO 5 to a single control voltage but also control sensitivity in the oscillation frequency of the VCO 5 when the control voltages are varied to a desired value.

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