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2013届本科生毕业设计

题目：基于matlab声音信号的滤波去噪处理

作 者 姓 名： 柯运生 学 号： 2009080313 院 （系）： 机械与电子工程学院 专 业： 电子信息工程 指 导 教 师： 邵 毅 蒋明曦 指导教师职称： 讲 师 工程师

2013年4月8日

SuZhou College

Year 2013 Bachelor Graduation Design

Title:Based on Matlab Voice Signal Filtering Denoising Processing

Author: Ke Yunsheng Student ID: 2009080313 Department: Collage of Mechanical and Electronic Engineering Major: Electronic and Information Engineering Instructor: Shao Yi Jiang Mingxi Professional Title: Lecture Engineer

April 8th, 2013

摘 要

在数字信号处理中,滤波器的设计占有极其重要的地位。而其中，FIR数字滤波器和IIR数字滤波器是重要组成部分。Matlab具有功能强大、简单易学、编程效率高等特点,深受广大科技工作者的喜爱。特别是Matlab中还具有信号分析工具箱,所以对于使用者，不需要具备很强的编程能力,就可以方便地进行信号分析、处理和设计。利用Matlab中的信号处理工具箱，可以快速有效的设计各种数字滤波器。本论文基于Matlab语音信号处理的设计与实现，综合运用数字信号处理的相关理论知识，对加噪声语音信号进行时域、频域分析并滤波。而后通过理论推导得出相应结论，再利用Matlab作为编程工具进行计算机实现工作。在设计实现的过程之中，使用巴特沃斯、切比雪夫和双线性变法设计IIR数字滤波器，使用窗函数法来设计FIR数字滤波器，并利用Matlab作为辅助工具，完成设计中的计算与图形的绘制。通过对所设计滤波器的仿真和频率特性的分析可知，利用Matlab信号处理工具箱，可以快捷有效地设计FIR和IIR数字滤波器，过程简单、方便，结果的各项性能指标也均达到指定要求。

关键字：Matlab；滤波器；IIR；FIR

ABSTRACT

In digital signal processing, filter design occupies an extremely important position. And among them, the FIR digital filter and IIR digital filter is an important part. Matlab has powerful function, easy to learn, programming efficiency higher characteristic, and was deeply loved by the masses of scientific and technical workers.Especially also has signal analysis toolbox in Matlab, so for users, don't need to have strong programming ability, can be easily signal analysis, processing and design. Signal processing toolbox of Matlab, can be used to quickly and efficiently design all kinds of digital filter. In this paper the design and implementation of speech signal processing based on Matlab, the integrated use of the relevant theoretical knowledge of digital signal processing, to add noise speech signal in time domain, frequency domain analysis and filtering. And then corresponding conclusion through theoretical derivation, using Matlab as a programming tool for computer implementation work. Implementation in the design process, using butterworth, chebyshev and bilinear reform IIR digital filter design, window function method used to design FIR digital filter, and by using the Matlab as an auxiliary tool, to complete the design of computing and graphics drawing. Through a simulation of the designed filter and frequency characteristic analysis shows that using the Matlab signal processing toolbox, can quickly and effectively to design FIR and IIR digital filter, the process is simple, convenient, and the results of various performance indicators meet the specified requirements.

Keywords：Matlab; Filter; IIR; FIR

目 录

绪论 ......................................................................................................................... 1 1 语音信号处理的基本知识 ..................................................................................... 3

1.1语音的录入和打开 ................................................ 3 1.2采样位数和采样频率 .............................................. 3 1.3时域信号FFT分析 ................................................ 3 1.4数字滤波器设计原理 .............................................. 4 2 Matlab相关函数 ................................................................................................... 5

2.1 wavread函数 .................................................... 5 2.2其他相关函数 .................................................... 5 3 去噪和仿真的研究 ................................................................................................ 7

3.1 语音文件在Matlab平台上的录入与打开 ............................ 7 3.2 原始语音信号频谱分析及仿真 ..................................... 7 3.3 加噪语音信号频谱分析及仿真 ..................................... 9 3.4 去噪及仿真 .................................................... 11 3.5 结合去噪后的频谱图对比两种方式滤波的优缺点 .................... 16 结论 ....................................................................................................................... 17 参考文献 ................................................................................................................ 18 致 谢 ................................................................................................................... 19