Patent ID: 7657237

Claim:
A method comprising: providing a transmitter having a baseband predistortor in a signal path of the transmitter, wherein a polynomial function represents a response curve of the transmitter; estimating one or more coefficients of the polynomial function of the response curve of the transmitter by: sending a predetermined input bit stream through the signal path, wherein the predetermined input bit stream is formed by at least two continuous wave tones, a signal level of each of the two continuous wave tones being less than a regulatory threshold but such that a total signal level of the two continuous wave tones combined being sufficient to drive a power amplifier in the transmitter into a nonlinear operating mode; applying a Fast Fourier Transform (FFT) operation to the predetermined input bit stream and to an output bit stream from the signal path that results from the predetermined input bit stream; and computing coefficients of the polynomial function based on results from the FFT operation applied to the predetermined input bit stream and to the output bit stream; computing predistortion coefficients for the baseband predistorter based on the one or more coefficients of the polynomial function.