Amplifier circuit with distortion cancellation

摘要

A circuit for amplifying an input signal includes an output amplifier that develops an output signal including distortion at a first magnitude and phase displacement when a signal of a second magnitude is applied thereto and a further amplifier wherein the amplifiers have substantially identical gains and distortion characteristics and are operated at substantially the same input and output levels. The further amplifier is included in a circuit responsive to the input signal wherein the circuit provides an intermediate signal to the output amplifier. The intermediate signal includes a first signal portion comprising a scaled version of the input signal and a second signal portion comprising distortion at substantially the first magnitude and at a phase displacement substantially 180 DEG out of phase relative to the first phase displacement. The output amplifier amplifies the intermediate signal and distortion in the output signal is substantially canceled by application of the second portion of the intermediate signal to the output amplifier.