| 摘要 |
PROBLEM TO BE SOLVED: To adaptively compensate nonlinear characteristics even when the amount of level change of an output average power in a time base direction in a device to be compensated becomes large. SOLUTION: A signal processing section captures the input/output signals of the device to be compensated, detects the time difference and phase difference of both signals, and obtains a distortion component from the amplitude and phase errors of both signals while matching the synchronization and the phases. A distortion correction section D sequentially selects the amount of compensation corresponding to the amplitude from the amounts of compensation which are registered in a compensation table in an initial stage and adaptively updated, adds the amount of the compensation to the input signal to compensate the distortion component and outputs the resultant signal to the device to be compensated. Through this configuration, a transient characteristic detection section H obtains the transient characteristic of the device to be compensated, and the distortion correction section D uses an adaptive filter I to give the inverse characteristic of the transient characteristic to the input amplitude and performs bank switching of the compensation table. Thus, the compensator can adaptively compensate the nonlinear characteristic by following a change in the nonlinear characteristic due to variations in the operating point of the device to be compensated. COPYRIGHT: (C)2004,JPO
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