| 摘要 |
PROBLEM TO BE SOLVED: To provide a distortion compensation circuit that attains a large compensation quantity and high-speed adaptive control. SOLUTION: An analog/digital converter 1 applies analog/digital conversion to an input signal. A linear filter 2 compensates linear distortion. A nonlinear filter 3 compensates nonlinear distortion left in an output of the linear filter 2. A transmission power amplifier section 4 applies digital/analog conversion to an output of the nonlinear filter 3 and supplies a transmission signal subjected to the digital/analog conversion, frequency conversion and amplification to an antenna. An output distortion detection section 5 applies frequency conversion to part of the transmission signal and outputs a digital output signal resulting from applying analog/digital conversion to a part of the transmission signal. A control section 6 detects the difference between the digital input signal and the digital output signal and respectively controls transfer functions of the linear filter 2 and the nonlinear filter 3 so as to minimize the detected error signal.
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