Patent ID: 7486744

Claim:
A distortion compensation apparatus comprising: a memory storing a distortion compensation coefficient in a designated write address, and outputting a distortion compensation coefficient being stored in a designated readout address; a predistortion section performing distortion compensation processing onto a transmission signal, using the distortion compensation coefficient being output from said memory; and a distortion compensation section calculating an update value of the distortion compensation coefficient, based on the error component existent between the transmission signal before said distortion compensation processing and the transmission signal after being amplified by an amplifier, wherein said distortion compensation section further comprises a function of controlling to modify a degree of effect of the error component produced on the update value, when calculating the update value of the distortion compensation coefficient wherein the modification of the degree of effect is realized by modifying the magnitude of the parameter to be multiplied by the error component, and wherein the distortion compensation section comprises: a memory storing a parameter in advance, corresponding to the integral value of the transmission signal before the distortion compensation processing or the transmission signal after being amplified by the amplifier; an integrator generating an integral value of the transmission signal before the distortion compensation processing or the transmission signal after being amplified by the amplifier; and a control means for reading out the parameter corresponding to the output of the integrator from the memory, wherein the parameter corresponding to the integral value is being set to a smaller value as the integral value becomes larger.