| 摘要 |
PROBLEM TO BE SOLVED: To provide a feedforward amplifier that does not deteriorate a distortion suppression amount even in the case of adopting a simple directional coupler. SOLUTION: A distortion detection directional coupler 8 of the feedforward amplifier consists of directional couplers 51, 54, an amplitude equalizer 52 and a phase equalizer 53. The coupler 51 outputs the output of a main amplifier received from an input terminal E1 to output terminals D1, D2 and the amplitude equalizer 52 and the phase equalizer 53 apply vector adjustment to the output from the output terminal D2 and provides an output. The directional coupler 54 outputs a distortion signal resulting from synthesizing a signal received from an input terminal E2 with the output of the phase equalizer 53 received from an input terminal E3 to an output terminal D3. Thus, the amplitude characteristics and the phase characteristic of the distortion detection directional coupler are constant with respect to the frequencies to be handled and the distortion detection directional coupler assures a distortion suppression amount with a sufficient margin against the standards of the amplitude/phase deviation and can absorb scatter in assembling works while employing simple components.
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