| 摘要 |
PURPOSE: A predistortion type digital linearizer and a gain control method thereof are provided which can obtain a signal of desired amplitude being output from a transmitter, by controlling a level of a digital input signal of a transmitter. CONSTITUTION: A gain control predistortion unit(300) controls a level of a digital input signal and distorts the digital input signal to have an opposite characteristics to a nonlinear distortion characteristics of a high power amplifier(30). An up converter(20) makes a radio frequency signal by performing a frequency upconversion of an output signal of the gain control predistortion unit. The high power amplifier performs a power amplification of the radio frequency signal being output from the up converter. A feedback unit(40) feeds back a signal being output from the high power amplifier and then performs a frequency downconversion of the signal. And an adaptation processing unit(400) controls the gain control predistortion unit adaptively, according to a digital signal of a baseband being output from the feedback unit and the delayed digital input signal and a desired output level.
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