毕业论文-基于LMS算法的自适应线性均衡器设计

I基于LMS算法的自适应线性均衡器设计摘要：在信息业快速发展的今天，进行快速准确的通信是各个行业的基本要求。影响移动通信质量和通信速度的一个重要因素是码间干扰，即串扰。在一个实际的通信系统中，基带传输系统不可能完全满足理想的波形传输无失真条件，因而串扰几乎是不可避免的。对串扰进行校正的电路称为均衡器，其实质是信道的一个逆滤波器。信道均衡器是通信系统中一项重要的技术，它能够很好的补偿信道的非理想特性，从而减轻信号的畸变，降低误码率。在高速通信、无线通信领域，信道对信号的畸变将更加的严重，因此信道均衡技术是不可或缺的。本文介绍了自适应均衡器的基本理论、最小均方(LMS)算法的原理与设计、自适应的基本原理、线性均衡器的基本理论与设计，并结合归一化(NLMS)算法、递归最小二乘法(RLS)算法对最小均方(LMS)算法作了进一步说明，最终用MATLAB对基于LMS算法的自适应线性均衡器进行了仿真设计。关键词：LMS算法；自适应；线性均衡器；(NLMS)算法；(RLS)算法LMSAlgorithmBasedonAdaptiveLinearEqualizerDesignAbstract：Therapiddevelopmentofinformationindustrytoday,forfastandaccuratecommunicationisthebasicrequirementofvariousindustries.Affectthequalityofmobilecommunicationsandthecommunicationspeedisanimportantfactorininter-symbolinterference,thatis,crosstalk.Inapracticalcommunicationsystem,base-bandtransmissionsystemcannotfullymeettheidealconditionsforwavetransmissionwithoutdistortion,thuscrosstalkisalmostinevitable.Thecrosstalkcorrectioncircuitcalledequalizer,anditsessenceisaninversechannelfilter.Channelequalizerisanimportantcommunicationsystemstechnology,itcanbewellcompensatednon-idealcharacteristicsofthechannel,therebyreducingthesignaldistortion,reducetheerrorrate.Inthehigh-speedcommunications,wirelesscommunications,channeldistortionofthesignalwillbemoreserious,sothechannelequalizationisindispensable.Thisarticledescribesthebasictheoryofadaptiveequalizer,theminimummeansquare(LMS)algorithmanddesignprinciples,basicprinciplesofadaptivelinearequalizerofthebasictheoryanddesign,combinedwithnormalized(NLMS)algorithm,recursiveleastsquares(RLS)algorithmforleast-mean-square(LMS)algorithmwasfurtherdescribed,andultimatelyusingMATLABLMSalgorithmbasedadaptivelinearequalizerforsimulationdesign.Keywords：LMSalgorithm;Adaptive;Linearequalizer;(NLMS)Algorithm;(RLS)AlgorithmII目录第1章绪论...................................................................................................................................................11.1均衡器研究背景及意义.............................................................................................................11.2国内外对均衡技术的研究动态.................................................................................................31.3本文研究内容和主要工作.........................................................................................................4第2章自适应均衡器基本理论...................................................................................................................52.1通信系统中的失真分析.............................................................................................................52.1.1、数字基带传输系统模型................................................................................................52.1.2通信系统中的噪声干扰..................................................................................................52.1.3、通信系统的传输特性....................................................................................................72.1.4、均衡技术........................................................................................................................82.2自适应滤波原理.........................................................................................................................82.2.1、自适应滤波器的分类....................................................................................................82.2.2、自适应滤波器的基本构成............................................................................................92.2.3、与普通滤波器的区别....................................................................................................92.2.4、自适应过程..................................................................................................................102.3自适应滤波结构.......................................................................................................................102.3.1、滤波器的实现结构......................................................................................................11第3章基于LMS算法自适应均衡原理.....................................................................................................143.1最小均方(LMS)算法基本原理.................................................................................................143.1.1、最佳滤波器准则..........................................................................................................143.1.2MMSE准则.......................................................................................................................143.1.3LMS迭代算法.................................................................................................................163.2最小均方（LMS）算法的性能分析.........................................................................................183.2.1LMS算法的稳定性.........................................................................................................183.2.2LMS算法的收敛速度.....................................................................................................203.2.3LMS算法的性能学习曲线及稳态误差.........................................................................21第4章基于LMS自适应均衡算法仿真...........................................................................