| 摘要 |
PROBLEM TO BE SOLVED: To secure a distortion removal amount over a wideband of frequencies. SOLUTION: A feedforward distortion compensation amplifier has a distortion detection loop, which branches an input signal into two signals so as to output either of them as a main amplified signal by amplifying it and extracts a distortion component in the main amplified signal by synthesizing the input signal with the main amplified signal with an opposite phase, equal amplitude, and an equal delay, and a distortion removal loop that amplifies the distortion component while delaying the main amplified signal and synthesizes the amplified distortion component with the distortion component in the delayed main amplified signal with an opposite phase, equal amplitude, and an equal delay so as to minimize a remaining distortion amount. Composite pilot signals of a plurality of tones are obtained by synthesizing a plurality of pilot signals after distributing an oscillated pilot signal into a plurality of pilot signals and shifting each frequency of the pilot signals by linearly modulating each phase of the pilot signals. The composite pilot signals of a plurality of tones are injected into the distortion detection loop by a coupler. Each phase and each amplitude of the distortion removal loop and those of the distortion detection loop are respectively controlled so as to minimize levels of a plurality of pilot signals detected from an output signal of the distortion removal loop and a distortion level detected by the distortion detection loop. COPYRIGHT: (C)2008,JPO&INPIT
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