matlab设计低通滤波器本科毕业论文.doc

摘 要 在当今的数字信息的世界里，数字信号处理已经演变成一门越来越重要的学科，在通信、语音、图像、自动控制、雷达、军事、航空航天、医疗和家用电器等众多领域得到了广泛的应用。其中数字滤波是数字信号处理的重要内容。数字滤波器可分为IIR和FIR两大类，对于IIR滤波器的设计来说主要有脉冲响应不变法和双线性变换法，而对于FIR数字滤波器的设计来说主要有窗函数法和频率采样设计法。 本文应用对数字低通滤波器进行仿真，并给出一定频率的信号通过所设计的滤波器来验证滤波器的性能，主要的研究工作主要包括以下几方面的内容: 介绍IIR滤波器和FIR滤波器的结构特点并比较两者之间的差别。 在中应用双线性变换法和脉冲响应不变法设计IIR滤波器，给出了滤波器的频率特性图和相位特性图。 通过编写程序用窗函数设计法和频率采样法来完成FIR低通滤波器的设计，并给出几个不同频率的信号通过所设定的滤波器来验证滤波器的性能。 在中应用模块来仿真FIR低通滤波器，并在示波器上同时显示输入信号的频率和输出信号的频率，最后对结果进行分析。 【关键字】 FIR滤波器 IIR滤波器, 双线性变换法 脉冲响应不变法 窗函数法 MATLAB  ABSTRACT In nowadays world of digital information, digital signal processing has become an increasingly important subject, and has been widely applied in all fields, such as medicine, communications, and other areas, digital filters are important elements of digital signal processing. Digital filters can be divided into two kinds of IIR and FIR, IIR filter design for pulse response method and bilinear transformation method, for FIR digital filter design, the main Windows function method and frequency of sampling design. In this paper simulation using MATLAB for digital low-pass filter, and to give a signal of a certain frequency through the filters designed to verify the performance of filter, the main research work mainly includes the following content: (1) Describes the structure of FIR and IIR filters filter characteristics and comparison of the differences between the two. (2) In MATLAB using bilinear transformation method and impulse response method design of IIR filters, to out of the filters of frequency response and phase characteristics. (3) Design method by writing MATLAB programs use the windows function and frequency sampling method to accomplish the design of FIR low-pass filters, and gives several different frequency signals passes through a set of filters to verify that the filters performance. (4) In the MATLAB Simulink simulation FIR low-pass filter module to the application, and also on the scope displays the frequency of the input signal a