Distortion compensation apparatus

Abstract

A step size parameter μ is adaptively varied when a distortion compensation coefficient is calculated in a distortion compensation apparatus, relation between transmission signal level and step size parameter μ is considered. The distortion compensation apparatus includes a memory storing distortion compensation coefficient in a designated write address, and outputting 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 memory; and a distortion compensation section calculating an update value of distortion compensation coefficient, based on error component existent between transmission signal before distortion compensation processing and transmission signal after being amplified by an amplifier. Further, the distortion compensation section modifies magnitude of step size parameter determining degree of effect of error component produced on the update value, when calculating the update value of the distortion compensation coefficient.

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