Orthogonal Basis Function Sets for Digital Predistorters

Abstract

A predistorter applies a distortion function to an input signal to predistort the input signal. The output of the distortion function is modeled as the sum of the output signals from the orthogonal basis functions weighted by corresponding weighting coefficients. Techniques are described for orthogonalizing basis function output signals according to the distribution of the input signals.

Description

Background technique [0001] The present invention relates generally to techniques for building physical models of nonlinear electronic devices, and more particularly to methods and apparatus for compensating input signals for distortions of input signals caused by electronic devices. [0002] The design of radio frequency power amplifiers for communication applications often involves a trade-off between linearity and efficiency. Power amplifiers are generally most efficient when operating at or near their saturation point. However, the response of an amplifier at or near its saturation point is nonlinear. In general, the response of a power amplifier exhibits non-linearity and memory effects when operating in the high efficiency range. [0003] One way to improve the efficiency of a power amplifier and its overall linearity is to digitally predistort the input to the power amplifier to compensate for the distortion caused by the power amplifier. In practice, the input signa...

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Problems solved by technology

However, the response of the amplifier at or near the saturation point is non-linear

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