Disclosed is an apparatus and method for modeling and estimating the characteristics
of a power amplifier with memory. A predistortion module generates a predistorted
signal in response to coefficients of a complex polynomial representative of the
amplifier and to an input signal. A power amplifier receives time-spaced samples
of the predistorted signal and generates an output signal. A polynomial module
updates the coefficients of the complex polynomial in response to a current sample
of the output signal and to the time-spaced samples of the predistorted signal.
In particular, the complex polynomial is implemented with both even and odd terms.
