Transmitter with limited spectral regrowth and method therefor

A method of processing a transmission signal to reduce spectral regrowth, said method comprising:

• transforming a modulated form of said transmission signal to generate a pre-distorted form of said transmission signal, said modulated form of said transmission signal being transformed in accordance with a pre-distortion function configured substantially as a polynomial in the form of a sum of a plurality of terms, wherein each of said terms includes a coefficient having a baseline component and an offset component;
• amplifying said pre-distorted form of said transmission signal in a power amplifier to generate an amplified form of said transmission signal;
• conditioning said amplified form of said transmission signal to generate a feedback signal;
• and
• processing said feedback signal to modify said pre-distortion function into a new pre-distortion function by identifying new offset components, then altering said baseline components in response to said new offset components.

A digital communication transmitter for transmitting a transmission signal occupying a predetermined frequency band while limiting spectral regrowth outside said predetermined frequency band, said transmitter comprising:

• a pre-distorter configured to receive a modulated form of said transmission signal, to transform said modulated form of said transmission signal in accordance with a pre-distortion function, and to generate a pre-distorted form of said transmission signal;
• a power amplifier coupled to said pre-distorter and configured to amplify said pre-distorted form of said transmission signal and to generate an amplified form of said transmission signal having an in-band component within said predetermined frequency band and an out-of-band component outside said predetermined frequency band;
• a conditioning circuit coupled to said power amplifier to condition said out-of-band component of said amplified form of said transmission signal, said conditioning circuit generating a feedback signal;
• and
• a processor coupled to said conditioning circuit and to said pre-distorter, said processor being configured to apply a genetic algorithm to said feedback signal and to modify said pre-distortion function.