功率放大器的线性化研究

Study on Linearization of Power Amplifier

在通信系统中,为了达到发射要求,信号要求具有较高的功率,需要通过高功率放大器对信号进行放大。功放非线性属于有源电子器件的固有特性,研究其机理并采取措施改善,具有重要意义。对功放的记忆效应和非线性特性进行分析研究,提出一种多项式预失真优化算法,利用和记忆多项式模型构建放大器的非线性模块,并在放大器模块前采用间接学习结构设计预失真器,利用最小二乘算法原理优化预失真器参数。仿真结果表明,预失真处理后输出信号的相邻信道功率比有较好的改善,接近理想功放线性化放大原则。改进算法使这两个模块的合成总效果可使整体输入-输出特性线性化,输出功率得到了充分利用。

In a communication system, high power amplifier will be needed to amplify signals to achieve the emis- sion requirements of signal with high power. The inherent non - linear characteristic of the power amplifier belongs to the active electronic devices, so studying its mechanism and taking measures to improve are of great significance. By studying the memory effect and nonlinear characteristics of the power amplifier, a predistortion optimization algorithm based on the polynomial was proposed. This algorithm builds an amplifier model on the basis of the memory polyno- mial structure, uses the indirect learning to design a predistorter before the amplifier module, and then uses the least square algorithm to optimize the predistortion derive parameters. The simulation result shows that, after the pre - dis- tortion processing, a better adjacent channel power ratio of the output signal was obtained, so it is close to the ideal linearization amplification principle of the power amplifier. The total effect of the two modules makes the overall input - output linearization and makes full use of the output power.