Linear distortion correction using a feedforward system

Abstract

The application of the feedforward amplifier linearization technique to the removal of both harmonic and intermodulation distortions is well understood and has been discussed in the literature. An additional benefit of the feedforward technique, which has received relatively little attention, is that of so-called linear distortion removal. Linear distortion is a term used to describe the nonideal gain and phase response (e.g., frequency response ripple) present in all practical amplifiers, and it is possible to significantly improve these parameters, in a practical application, using the feedforward technique. This paper discusses the improvements in this area, which may be achieved by utilizing the feedforward technique, demonstrates mathematically how they arise, and presents both simulation and practical results to demonstrate the effect for various types of gain and phase response nonlinearity.