| 摘要 |
PURPOSE: A pre-feedforward linear power amplifier is provided to be capable of improving an efficiency of the linear power amplifier. CONSTITUTION: An inter-modulation distortion(IMD) generating part imitates IMD and consists of a mimic amplifier(59), a signal canceller amplifier(57), and a vector modulator(58). The mimic amplifier(59) imitates the IMD generated from a main amplifier(70), and the signal canceller amplifier(57) removes an originally inputted signal from the imitated signal. A cancelling coupler(61) reversely couples a signal distorted by a nonlinear characteristic with an original signal. An error amplifier(66) amplifies an extracted IMD component, and an IMD canceling coupler(67) is supplied with the amplified IMD component. A vector modulator(63) adjusts an amplitude and a phase of the imitated IMD. The IMD canceling coupler(67) amplifies the distorted signal and the imitated IMD so as to be coupled reversely, so that the originally inputted signal is amplified.
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