| 摘要 |
A distortion compensation apparatus in a mobile radio transmitter using multiple carriers within a given transmission bandwidth. The apparatus includes a distortion compensation processing circuit (91) multiplying an input signal (BBS) by a distortion compensation coefficient; a distortion compensation coefficient storage (90) storing the distortion compensation coefficient correspondingly to the input signal power; a distortion compensation coefficient calculator (92) calculating an update value of the distortion compensation coefficient stored in the distortion compensation coefficient storage, based on the input signal and a feedback signal being fed back from the output side of a distortion device; and a digital filter (100) receiving the output of the distortion compensation processing circuit (91). Further is included a modifying unit (101), which modifies the passband of the digital filter (100) so as to reduce a distortion compensation control bandwith in the predistortion portion, in response to the reduction of the number of carriers in the input signal. The apparatus can thus adapt to the number of carriers being used so as to avoid an increase in unwanted radiation outside the transmission bandwidth.
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