In a distortion injection path (15) wherein a detected distortion component of a main amplifier (23) becomes amplified, distortion by an auxiliary amplifier (29a) is detected by an auxiliary distortion detector (42) composed of a variable attenuator (27a), a variable phase shifter (28a), a first auxiliary...http://www.google.de/patents/US6320464?utm_source=gb-gplus-sharePatent US6320464 - Feedforward amplifier
