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.