Lineariser with broadband predistortion and temperature self-compensation for microwave amplifier

摘要

The device includes an input divider (22) which divides an input signal between two transmission lines and introduces a 90 degree phase shift between the two outputs. The divider is preferably a microstrip coupler. In a nonlinear channel, an amplifier (14) generates amplitude distortion and is followed by a variable attenuator (23) and a phase shifter (29). In the linear channel, one output of the coupler is terminated with a matched load (8), and the other feeds a variable phase shifter (19), attenuator (13) and microwave amplifier (4). The predistortion correction signal is taken from one output (6) of a coupler (15) which is preferably a hybrid ring, introducing a 90 deg. phase shift before combining. The first and second channel circuitry is identical. IMAGE