Article comprising a power amplifier with feed forward linearizer using a tracking algorithm

摘要

A feedforward linearizer (60) for amplifying an input signal comprises a signal cancellation circuit (86) which has a first signal cancellation branch (62,64,66) and a second signal cancellation branch. A first amplifier (62) provided in the first signal cancellation branch is configured to receive the input signal intended to be amplified. A signal cancellation vector modulator (66) is coupled to the first amplifier and configured to receive an output signal provided by the first amplifier. A signal cancellation adder (68), coupled to the signal cancellation vector modulator, is configured to receive the signal generated by the signal cancellation vector modulator and configured to receive the input signal via the second signal cancellation branch and to provide an error signal. An error cancellation circuit (88) has a first error cancellation branch (74) and a second error cancellation branch (70,72). An error cancellation adder (74) in the first error cancellation branch is configured to receive the output signal provided by the first amplifier (62). The output of the error cancellation adder provides the output signal of the linearizer. An error cancellation vector modulator (70) in the second error cancellation branch is configured to receive an error signal provided by the signal cancellation adder and provides an error adjusted signal.;A second auxiliary amplifier (72) coupled to the error cancellation vector modulator is configured to provide an input signal to the error cancellation adder. A digital signal processor (76) is configured to provide a signal cancellation adjustment signal, α, to the signal cancellation vector modulator and an error cancellation adjustment signal, β, to the error cancellation vector modulator respectively, such that the output signal of the signal cancellation adder is a signal that substantially represents the error components provided by the first amplifier, and the output signal of the error cancellation adder is an amplified version of the input signal, with substantially no intermodulation components.