功放数字基带预失真理论分析和仿真实现

为了消除功放非线性带来的失真,满足制定的功率谱密度要求,自适应数字基带预失真技术以其良好的线性度、宽带宽、高效率和全自适应性等优点而成为消除功放失真的首选.从几种线性化技术的比较开始,介绍了两种数字预失真结构,给出了数字基带预失真的工作原理,构建了数字基带预失真电路并在ADS环境下实现了系统级仿真.仿真结果表明构建的数字基带预失真系统能够获得好的预失真效果,功率谱密度的最大改善能够达到30dBm.创建的系统级仿真电路对实际的数字预失真系统设计起着重要的指导作用.

Theoretical Analysis and Simulation Implementation of Adaptive Digital Baseband Predistortion for PA

In order to cancel nonlinear distortion of power amplifier (PA) and meet the requirement of power spectral density mask specified by regulatory bodies, an adaptive digital baseband predistortion technique have been applied because of many advantages such as good linearity, wide bandwidth, high efficiency and full adaptation and become first choice of canceling distortion of nonlinear PA. Starting from comparison with a few linearization techniques, two kinds of digital predistortion structures were introduced, and operating theory of digital baseband predistortion was given, and digital baseband predistortion circuits and implement system-level simulation in ADS circumstance were built. Simulation result shows that created digital baseband predistortion system can obtain good predistortion effect. The created system-level simulation circuit plays an important role in designing practical predistorter.