非线性M-QAM信道的自适应预均衡

Adaptive Pre-Equalization in Non-Linear M-QAM Channels

本文介绍一种数字式自适应预均衡器.它可以补偿高功率放大器在非线性区域工作时引入的具有记忆的3阶非线性失真.采用 Volterra 级数表示法分析这种非线性失真,并对高功率放大器参数进行自适应估值,从而完成预均衡网络和估值电路的设计.本文同时给出 M-QAM 系统的计算机模拟方法.模拟结果表明,这种预均衡器对系统的非线性失真有较好的校正作用.

This paper presents a kind of adaptive digital pre-equali- zer,The pre-equalizer can make up for the memorized third order non-linear distortion caused by high power amplifier (HPA)working in non-linear domain.This third order non- linear distortion is studied by the Volterra series representation and the parameters of HPA are adaptive predicted.We fulfil the designs of pre-equalization networks and predication circuits. Then,a kind of adaptive digital pre-equalizer is obtained. This paper also gives the computer simulation method for M-QAM system.When the M-QAM system has or has not the pre-equalization,the results of computer simulation of the memo- rized non-linear M-QAM digital transmission system are given. It shows that this kind of adaptive digital pre-equalizer has better correction and compensation effect for systematic non- linear distortion.