| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a transmission circuit capable of achieving a wider bandwidth of a control band while securing a pressure resistance in a built-in voltage control unit. Ž<P>SOLUTION: The transmission circuit includes: a phase modulation unit for phase-modulating a phase signal to output a phase-modulated signal; a power amplifier including a transistor; a collector control unit for controlling a collector voltage of the transistor; a base control unit for controlling a base bias voltage of the transistor; and a switching control unit for switching only control over the collector control unit to control corresponding to an amplitude signal and a power level signal when the power level of a power level signal is less than a predetermined value, and for switching only control over the base control unit to control corresponding to the amplitude signal and the power level signal when the power level of the power level signal is a predetermined value or over, wherein the power amplifier amplifies a phase modulation signal based on the collector voltage and base bias voltage that are controlled by the collector control unit and base control unit. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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