功率放大器非线性特性及预失真建模

Power Amplifier's Nonlinear Feature and Pre-distortion Modeling

信号的功率放大器是电子通信系统的关键器件之一,功放的输出信号相对于输入信号可能产生非线性变形,这将带来无益的干扰信号,研究其机理并采取措施改善,具有重要意义.通过利用无记忆非线性功放和记忆非线性功放的实测数据用数学方法对其分别进行建模,而后使用前置预失真器的方法改善功放的非线性特性,并对其中预失真器的建模做了研究,采用间接学习型结构构建预失真器模型.仿真结果显示功放非线性模型结合预失真器模型能够很好地逼近实际情况,并且能很好地抑制带外频谱扩展.

The power amplifier （PA for short） for signal is one of the key components for the electronic communication system. It will bring interference signals if the PA＇s output signal became nonlinear compare with the input signal. Therefore, it＇s very important to do some research on its mechanisms and measures. In this paper, we will use the data from memory- less and memorial nonlinear PA to model with mathematical functions. After that, we will take the pre-distortion device to improve the PA＇s nonlinear feature and make a study of its model. With the help of the indirect-learning structure, the result shows that the model of nonlinear PA combined with the pre-distortion device can approach the real state well. At the same time, the model can also restrain OOB frequency spectrum spreading effectively.