FEEDFORWARD AMPLIFIER, METHOD FOR CONTROLLING FEEDFORWARD AMPLIFIER AND BASE STATION WITH FEEDWARD AMPLIFIER

摘要

PROBLEM TO BE SOLVED: To stably output an amplification signal with low distortion by reducing the backoff of an amplifier and improving power efficiency, in the feedforward amplifier and controlling method therefor which are suitable to be used for a radio communication system such as a digital automobile telephone, etc., and a base station with feedforward amplifier. SOLUTION: In the feedforward amplifier provided with a distortion extraction loop circuit part 1 which is provided with a main amplifier 5 amplifying the main signal of a main signal system and generates the distortion extraction signal canceled with the main signal component of the outputs of the main amplifier 5 based on the phase control of the main signal and a distortion elimination loop circuit part 9 using the distortion extraction signal canceled with the main signal component on the poststage side of the main amplifier 5 and outputting only the main signal component from the signal of the main signal system on the poststage side of the main amplifier 5, the distortion extraction loop circuit part 1 generates the distortion extraction signal by executing a phase control to the main signal while shifting from the phase control point where the main signal is maximumly canceled.