摘 要
随着信息时代和数字世界的到来，数字信号处理已成为一门极其重要的学科和技术领域。数字信号处理在通信、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。在数字信号处理应用中，数字滤波器十分重要并已获得广泛应用。语音信号处理是研究用数字信号处理技术对语音信号进行处理，处理的目的是用于得到的某些参数以便高效传输和存储;或者应用于人工合成、语音识别和语音增强等。
本文利用MATLAB图形用户界面(GUI)的操作灵活、界面简洁直观等优点，采用了巴特沃斯、椭圆、切比雪夫Ⅰ型和切比雪夫Ⅱ型四种模拟低通滤波器，并分别由脉冲响应不变法、线性变换法转换为数字滤波器，对添加了噪声的语音信号进行去噪处理，通过滤波器去噪后的声音的播放及信噪比对比，理解各个模拟滤波器由不同方法转化的数字滤波器的优劣。
首先是对无噪语音进行频谱分析，然后对其加噪声并对加噪后的语音进行频谱分析。分别采用脉冲响应不变法和双线性变换法设计出了无限长单位冲激响应(IIR)数字滤波器。并完成对加噪语音的去噪处理。通过计算比较去噪后语音信号的信噪比不同从而得出不同类型滤波器的优劣。最终借助GUI设计了语音信号去噪系统的图形用户界面，增强了系统程序的可视性和友好性。
关键词：MATLAB；GUI；滤波器；语音识别；语音信号
Abstract
With the advent of the information age and the digital world, digital signal processing has become an extremely important discipline and technical field. Digital signal processing has been widely used in many fields including communication, communication, voice, image, automatic control, radar, military, aerospace, medical and household appliances. In the digital signal processing application, the digital filter is very important and has been widely used. Speech signal processing is applied by digital signal processing technology for efficient transmission and storage, or to artificial synthesis, speech recognition and speech enhancement.
This paper using the flexible operation of MATLAB graphical user interface (GUI), simple interface intuitive, adopted Butterworth, ellipse, Chebyshev I and Chebyshev type four kinds of analog low-pass filter, and respectively by the pulse response method, linear transformation method to digital filter, to add the noise signal noise processing, through the noise of sound playback and signal to noise ratio comparison, understand the quality of the analog filter by different methods of digital filter. First, the spectrum analysis of the noise-free speech, and then the noise and the noise-added speech. The infinite length unit impulse response (IIR) digital filter is designed by the impulse response method and double linear transformation method respectively.
And complete the denoising processing of the noise-added speech. The advantages of different types of filters are obtained by comparing the SINR of speech signals. Finally, the graphical user interface of the voice signal denoising system was designed with the help of the GUI to enhance the visibility and friendliness of the system program.
Key words: MATLAB; GUI; filter; speech recognition; speech signal
目录
摘 要
Abstract
1 绪论
1.1 研究背景
1.2 国内外研究现状
1.2.1 国内研究现状
1.2.2 国外研究现状
1.3 IIR数字滤波器的设计内容
2 数字滤波器的设计与研究
2.1 数字滤波器工作原理
2.2 数字滤波器分类
2.3 IIR数字滤波器基本结构
3 IIR数字滤波器的设计
3.2 脉冲响应不变法
3.3 双线性变换法
4 基于MATLAB对IIR数字滤波器的设计
4.1 语音信号采集、读取、加噪
4.2 模拟滤波器的设计
4.3 双线性变换法设计Butterworth数字滤波器
4.4 脉冲不变响应法设计Chebyshev I数字滤波器
4.5 语音信号滤波处理结果比较
5 IIR数字滤波器去噪平台GUI界面设计
5.1 IIR数字滤波器去噪平台GUI界面设计流程
5.2 IIR数字滤波器去噪平台界面设计
5.2.1 原始语音模块设计
5.2.2 加噪语音模块设计
5.2.3 滤波器模块设计
5.2.4 退出模块设计
6 总结
6.1 滤波器设计中存在的不足
6.2 总结以及展望
