Patent ID: 7663436

Claim:
A power amplifier having a distortion compensation circuit, which compares a input signal power against a sampled component of an output power, and provides predistortion to the input signal power so as to minimize a difference as a result of the comparison, the power amplifier comprising: a gain lookup table storing a gain coefficient value corresponding to a temperature address determined for an input power; a phase lookup table storing a phase coefficient value corresponding to the temperature address determined for the input power; a transversal filter, which is input with the input power, and which outputs the temperature address; and a coefficient multiplier modulating the input signal using a gain coefficient value and a phase coefficient value, which correspond to the temperature address and which are read out from the gain coefficient lookup table and the phase lookup table, wherein a gain coefficient value and a phase coefficient value, which are respectively stored in the gain lookup table and phase lookup table, are determined by applying a pulse signal having a pulse width Tw, an amplitude Ak, and a pulse duration Td, as input, taking the amplitude difference with the output power detected at this time as Ad (Tw, Ak, Td) and taking the phase difference with the output power detected at this time as φd (Tw, Ak, Td), measuring an amount of change of the amplitude difference Ad and an amount of change of the phase difference φd when the amplitude Ak is changed by ΔA, and defining the respective change ratios Gd, Pd by the following equations: Gd={Ad ( Tw,Ak,Td )− Ad ( Tw,Ak+ΔA,Td )}/Δ A Pd={φd ( Tw,Ak,Td )−φ d ( Tw,Ak+ΔA,Td )}/Δ A, the Gd and Pd being respectively set as the gain coefficient value and the phase coefficient value stored in the gain lookup table and phase lookup table.