Transmitter with limited spectral regrowth and method therefor

摘要

A transmitter for a digital transmission signal includes a pre-distorter to improve linearity of a power amplifier. An amplified transmission signal is conditioned into a narrowband feedback signal that is responsive to a logarithm of the power appearing in out-of-band components of the amplified transmission signal. The feedback signal is processed in a pre-distortion processor that implements a genetic algorithm to adapt pre-distortion functions implemented in the pre-distorter and improve linearity over time. The genetic algorithm tests a population of randomly-generated pre-distortion functions for fitness. A baseline component of the coefficients from pre-distortion functions used in a subsequent population tracks the best-fit pre-distortion function from the current population, allowing the use of a limited search space. New populations are generated from old populations using an elitism process, and randomized crossover, and mutation processes.