基于matlab的fir滤波器设计.doc

目录 

 

摘要 5

Abstract 6

1 绪论 7

1.1 选题的依据和意义 7

1.2 数字滤波器的研究背景 7

1.3 数字滤波器的应用和现状 8

1.4 MATLAB简介 8

2 FIR滤波器的线性相位 9

2.1 FIR滤波器的概述 9

2.2 FIR滤波器线性相位的定义 10

2.3 FIR滤波器线性相位约束条件 10

3 FIR滤波器的设计方法 11

3.1 窗函数设计法 11

3.1.1 窗函数法的设计思路 11

3.1.2 吉布斯效应 13

3.1.3 几种典型窗函数的介绍 13

3.1.4 窗函数法具体设计实例 15

3.2 频率采样法 19

3.2.1 频率采样法的设计思路 19

3.2.2 频率采样法的设计步骤与实例 20

3.3 等波纹逼近法及设计实例 23

3.4 不同设计方法间的比较 26

4 基于MATLAB的FIR滤波器设计 27

4.1 窗函数法的MATLAB实现 27

4.2 频率采样法的MATLAB实现 33

4.3 等波纹逼近法的MATLAB实现 34

5 总结 38

6 致谢 39

7 参考文献 40

附录 41

   程序1 41

   程序2 43

   程序3 44

基于MATLAB的FIR滤波器设计

摘要

    FIR滤波器是组成数字信号处理中一个比较关键性的部分，因为它有着严格线性相位，所以它在信号处理过程当中被普遍地采用。本文主要涉及FIR滤波器的基本概念以及具备线性相位的条件，主要分析用窗函数法，频率采样法以及等波纹逼近法来设计FIR滤波器的思路、流程，进行程序编写设计。对比仿真设计结果可以得出：选择用这三种设计法设计出来的FIR滤波器，从相频上来看，它们在通带内，都是具有线性相位的；而从幅频特性上来看，等波纹逼近法相对于另外两种设计法来说，设计出来的FIR滤波器具有边界频率精确，阶数低，平坦的通带和阻带以及过渡带窄。

关键词：FIR低通滤波器，MATLAB，窗函数法，频率采样法，等波纹逼近法

The design of FIR filter based on MATLAB

Abstract

  FIR filter is composed of a more critical part of the digital signal processing, because it has a strict linear phase, so it is widely used in the signal processing. This article mainly involves the basic concept of FIR filter, and have the conditions of the linear phase, the main analysis the thought of method using window function, frequency sampling method and equiripple approximation method to design, process of FIR filter to design programming.Comparative simulation results can be concluded that: choose the three design of FIR filter design method, from the phase frequency point of view, they within the passband, are all with linear phase; And on the amplitude-frequency characteristic of it, such as corrugated equiripple approximation method for the other two kind of design method, the design of FIR filter with boundary frequency precision, low order, flat passband and stopband and narrow transition band.

Key words：FIR low-pass filter，MATLAB，Windowing method，Frequency sampling method，Equiripple approximation method