毕业设计-基于MATLAB的IIR数字滤波器的设计.doc

IIR数字滤波器的设计 摘 要 数字滤波器是对数字信号进行滤波处理以得到期望的响应特性的离散时间系统。作为一种电子滤波器，数字滤波器与完全工作在模拟信号域的模拟滤波器不同。数字滤波器工作在数字信号域，它处理的对象是经由采样器件将模拟信号转换而得到的数字信号。数字滤波器的工作方式与模拟滤波器也完全不同：后者完全依靠电阻、电容、晶体管等电子元件组成的物理网络实现滤波功能；而前者是通过数字运算器件对输入的数字信号进行运算和处理，从而实现设计要求的特性。 本文由数字滤波器的功能、应用及发展入手，介绍了数字滤波器的基本概念，其中包括系统的描述、系统的传递函数和IIR数字滤波器基本结构。其次根据IIR数字滤波器的设计原理，在MATLAB环境下分别采用脉冲响应不变法、双线性变换法和MATLAB函数直接设计法对IIR数字滤波器进行了设计。最后应用FDATool和Simulink工具对IIR数字滤波器进行了仿真。 关键词：IIR数字滤波器；MATLAB；脉冲响应不变法；双线性变换法；FDATool； Simulink Design of IIR digital filter Abstract Digital filters are the discrete-time systems that process to filter digital signal to get expected response characteristics. As an electronic filter, digital filters work differently from the analog signal filters who completely work in analogy signal domain. Digital filter work in the digital signal domain and its targets are digital signals that are received by sampling devices converting analog signals to digital signals. The working methods of digital filters and analog filters are completely different: the latter completely rely on the function of the physical network formed by resistors, capacitors, transistors and other electronic components of filtering ,while the former computes and processes digital signals with the help of digital computing devices to realize the characteristics of the design requirements. In this paper, the function, application and development of the digital filter are introduced followed by the introduction of the principle of digital filter design. The principle first includes the description of the system, the transfer function of the system and the basic structure of the IIR (Infinite Impulse Response) digital filter. Then, according to the design principle of IIR digital filter, the IIR digital filter is designed by the method of non-changing impulse response, the method of double linear transform and direct method using MATLAB functions. At last, the designed IIR digital filter is simulated by FDATool and MATLAB Simulink Tool. Key words: IIR d