| 摘要 |
A transmitter apparatus that exhibits a high efficiency and that can provide a wide variable output control width. An operation of saturation mode is performed in the vicinity of the maximum transmission power. A large-power amplifier ( 12 ) is caused, by increasing and then fixing the input level thereof, to operate in a saturation state, while the amplitude component of a modulation signal in a range corresponding to an output power control level is inputted to an R-input terminal (33) to amplitude modulate the power supply voltage (VDD) of a power supply terminal ( 25 ), thereby performing a polar coordinate modulation of a high efficiency. An operation of linear mode is performed for a smaller transmission power. The large-power amplifier ( 12 ) is caused, by reducing the input level thereof, to perform a linear operation, while the power supply voltage (VDD) of the power supply terminal ( 25 ) is varied in accordance with the output power control level, thereby performing a transmission power control.
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