Transmitter linearized using bias deviation gain adjustment and method therefor

Abstract

A transmitter () includes a low power memoryless nonlinear predistorter () that inserts predistortion configured to address a nonlinearity () corresponding to gain droop and another nonlinearity () corresponding to deviations from an average bias condition. When efforts are taken to reduce memory effects, such as configuring a network of components () that couple to an HPA () to avoid resonance frequencies within a video bandwidth (), high performance linearization at low power results without extending linearization beyond that provided by the memoryless nonlinear predistorter (). Each nonlinearity is addressed by applying gain to a communication signal (). The amount of gain applied is determined by a look-up table () for one nonlinearity () and by a look-up table () in combination with a differentiator () for the other nonlinearity (). The look-up tables () are updated in accordance with modified LMS control loops.