李婉雪-毕业设计-20104470

本科学生毕业论文2010年5月9日论文题目：自适应噪声对消原理与实现学院：电子工程学院年级：2010级专业：通信工程姓名：李婉雪学号：20104470指导教师：平义和I摘要自适应滤波器的系数可随外界参数的变化而自动调整，并且始终保持最优滤波，所以它已经被广泛应用于系统辨识、信号增强、通信信道均衡、信号预测等领域，其中自适应噪声对消是自适应滤波器的主要应用形式之一。随着信号与信息处理技术的发展，自适应信号处理应用领域也越来越广，自适应滤波器的研究及其硬件实现成了近年来信号处理领域研究的热点与难点问题之一。本文主要讲述了数字滤波器，自适应滤波器，最小二乘法拟合的原理，MATLAB仿真软件的简介以及使用RLS(RecusiveLeastSquares)递归最小二乘算法进行了详细的理论推导；最后在MATLAB平台上，通过编写自适应噪声对消滤波器的程序，改变自适应参数（滤波器阶数、迭代步长、遗忘因子等），以分别通过经最小二乘法计算系数的自适应滤波器与普通滤波器后的序列与原随机序列的误差，进行了一系列的仿真和比较分析，来说明自适应滤波器在噪声消除方面具有更的优势。关键词数字滤波器；自适应滤波器；RLS（递归最小二乘法）；MATLAB；噪音消除IIAbstractSincethecoefficientofadaptivefiltercanchangeautomaticallywiththeparameters’changefromoutsideandkeepinexcellentfilter,ithasbeenwidelyusedinSystemIdentification,SignalEnhancement,CommunicationChannelEqualizationandSignalPrediction,etc,andAdaptiveNoiseCancellationisthemostimportantone.Adaptivesignalprocessinghasbeenusedmoreandmorefrequentwiththedevelopmentofsignalandinformationprocessingtechnology,sotheresearchandhardwareimplementationofadaptivefilterhasbecomeahotspot.Thepaperisaboutthedigitalfilter,adaptivefilter,theintroductionofleastsquaresfitting,principleandthederivationofRLS(RecusiveLeastSquares);Atleast,changetheadaptationparameters(filterorder,iterativestep,forgettingfactor,etc.)andwirteprogramabouttheerrorofrandomgaussianwhitenoisewhothroughtheadaptivefilterwiththeparametercalculatedbyRLSorthecommonfilteronMATLABstage,comparethemtoexplaintheexcellenceofadaptivefilter.Keywordsdigitalfilter;adaptivefilter;RLS(RecusiveLeastSquares);MATLAB;noisecancellation目录摘要............................................................................................................................................IAbstract...................................................................................................................................II前言...........................................................................................................................................1第一章绪论.............................................................................................................................21.1数字滤波器的表示方法............................................................................................21.2无限长单位冲击响应（IIR）滤波器的基本结构..................................................21.3有限长单位冲击响应（FIR）滤波器的基本结构..................................................5第二章自适应滤波器.............................................................................................................72.1自适应滤波器导论....................................................................................................72.1.1自适应信号处理.............................................................................................72.1.2自适应滤波器的应用.....................................................................................82.1.3自适应滤波器结构.......................................................................................102.2自适应滤波器算法..................................................................................................112.2.1自适应算法介绍...........................................................................................112.2.2自适应算法分类...........................................................................................12第三章自适应噪声对消原理...............................................................................................133.1最小二乘法..............................................................................................................133.1.1最小二乘法基本原理...................................................................................133.1.2多项式拟合...................................................................................................143.2最小二乘法在自适应噪声对消中的应用..............................................................153.2.1自适应噪声对消原理...................................................................................153.2.2算法推导过程...............................................................................................17第四章自适应噪声对消的实现...........................................................................................194.1MATLAB软件介绍.....................................................................................................194.1.1MATLAB语言的特点......................................................................................194.1.2MATLAB的技术特点......................................................................................194.1.3MATLAB功能特点..........................................................................................214.2自适应滤波器的设计...............................................................................................224.2.1最小二乘法设计自适应滤波器.....................................................................224.2.2运行结果.........................................................................................................23结论.........................................................................................................................................25参考文献...........................................................................................