Abstract: Disclosed is an apparatus and method for calculating a predistortion function from power amplifier characteristics. A predistortion module generates a predistorted signal in response to an input signal and predistortion coefficients received from a predistortion function calculating module. The predistortion function calculating module generates the predistortion coefficients in response to the given amplifier characteristics. Polynomial fitting is used to obtain the predistortion coefficients. In particular, the input signal is represented by single or multiple sectors having multiple points and then predistortion coefficients are calculated for each sector.