Patent ID: 7251290

Claim:
An adaptive controller for adjusting the gain of a bank of complex gain elements to provide a predistorted input signal to a non-linear transmitter, the controller comprising: a first delay coupled to an input signal; an error phase normalizer coupled to the delayed input signal and a feedback signal from the transmitter, that provides a phase-normalized input and a phase-normalized feedback signals; a combiner coupled to outputs of the error phase normalizer, that provides a complex error signal defined as the difference between combiner outputs; a second delay coupled to the predistorted input signal from the gain elements; a controller selector coupled to the input signal; a bank of linear controllers coupled to the controller selector and the combiner, each linear controller comprising: a phase state estimator coupled to the feedback signal and the predistorted signal; an error rotator receiving the complex error and coupled to the phase state estimator; an error scaler coupled to the error rotator and an accumulator coupled to it for providing complex gain values for the bank of complex gain elements.