Feedforward amplifier

A communications station unit provided in a mobile communications system that uses a feedforward amplifier to amplify a multi-carrier signal with respect to the other party in communications, compensates for the distortion generated at the time of this amplification, and wirelessly transmits this amplified signal to the other party in communications, wherein:

• said feedforward amplifier has a constitution whereby it inputs a plurality of signal groups, each having a different frequency bandwidth respectively, and that in a distortion detection loop uses a main amplifier to amplify this plurality of input signal groups and detect the distortion arising in said main amplifier, and in a distortion compensation loop removes the distortion detected in the distortion detection loop from the amplified signal from said main amplifier, and
• in said feedforward amplifier, the distortion compensation loop has the same number of distortion amplification systems as the number of input signal groups that use an auxiliary amplifier to amplify distortion in each input signal group that contains distortion detected by the distortion detection loop, and that removes the sum total of the distortion of each input signal group amplified by this plurality of distortion amplification systems from the amplified signal from the main amplifier.