数字信号处理课程设计报告.docxVIP

信息工程学院数字信号处理课程设计数 字 信 号 处 理课程设计报告题目： 数字调音台 学院： 信息工程学院 专业： 通信工程 指导教师： 指导时间: 姓 名学号承担任务指导教师评价意见成绩24目 录1 背景与内容12 设计目的13 设计原理13.1 研究语音信号的特点；13.2 IIR数字滤波器23.3 滤波器设计所涉及的matlab函数23.4 总体方案34 设计过程44.1 系统流程图44.2 具体设计45 实验代码及结果75.1 MATLAB源程序75.2 系统运行与测试196 实验体会及总结247 参考文献241.背景与内容根据数字信号处理课程设计教学大纲的要求，利用Matlab（工程设计软件）设计数字调音台，并且给出了具体的软件实施方案。Matlab功能强大、简单易学、编程效率高,深受广大科技工作者的欢迎。特别是Matlab还具有信号分析工具箱,不需具备很强的编程能力,就可以很方便地进行信号分析、处理和设计。此次设计利用Matlab对音频信号进行采样后；并画出音频信号的时域波形、频谱图；然后利用IIR设计高通、低通、带通以及帯阻滤波器对现有的音频信号进行滤波，实现音频音色的改变实现调音台的功能，并画出滤波后信号的时域波形和频谱，对滤波前后的信号进行对比，分析信号的变化；最后利用GUI设计一个数字信号系统界面。1、选一首歌曲，采用已经学过的信号处理知识，设计高通、带通、低通、带阻几种滤波器，对其进行数字信号滤波，观察信号的变化；2、实时显示处理前的信号频谱和处理后的信号频谱；3、设计系统界面：为了使编制的程序操作方便，设计处理系统的用户界面，在所设计的系统界面上可以选择滤波器的类型，输入滤波器的参数、显示滤波器的频率响应等。2.设计目的1、通过对常用数字滤波器的设计和实现，掌握数字信号处理的工作原理及设计方法；熟悉用 IIR 数字滤波器和FIR滤波器的原理与方法，掌握利用数字滤波器对信号进行滤波的方法 2、掌握数字滤波器的计算机仿真方法，并能够对设计结果加以分析。3、通过对Matlab的使用，掌握Matlab的程序设计方法，掌握Matlab设计IIR数字滤波器和FIR滤波器的方法，并学会用Matlab对信号分析和处理。4、学习使用MATLAB GUI设计工具应用平面。3.设计原理3.1研究语音信号的特点；语音信号的带宽约为5KHz，主要能量集中在低频段。语音信号是典型的随机信号，人的每次发音过程都是一个随机过程。很难得到两次完全相同的发音样本。 语音时域信号特征1）清音段：能量低，过零率高，波形特点有点像随机的噪声。这部分信号常与语音的辅音段对应。 2）浊音段：能量高，过零率低，波形具有周期性特点。所谓的短时平稳性质就是处于这个语音浊音（元音）段中。 3）过渡段：一般是指从辅音段向元音段信号变化之间的部分。信号变化快，是语音信号处理中最复杂、困难的部分。 3.2 IIR数字滤波器设计IIR数字滤波器一般采用间接法（脉冲响应不变法和双线性变换法），应用最广泛的是双线性变换法。基本设计过程是：先将给定的数字滤波器的指标转换成过渡模拟滤波器的指标； 设计过渡模拟滤波器；将过渡模拟滤波器系统函数转换成数字滤波器的系统函数。3.3滤波器设计所涉及的matlab函数y,fs= wavread(wavFile1)，此函数能读取.wav格式的音频文件。其中y为语音信号，fs为采样频率，wavFile1为WAV音频文件存放路径。N,wc=buttord(wp,ws,Rp,As)，用于计算巴特沃斯数字滤波器的阶数N和3dB截止频率 wc。调用参数wp，ws分别为数字滤波器的通带、阻带截止频率的归一化值，要求：0 wp1，0ws1。1表示数字频率pi。 rp，rs分别为通带最大衰减和组带最小衰减（dB）。 当wswp时，为高通滤波器；当wswp时，为低通通滤波器；当wp和ws为二元矢量时，当wslwplwpuwsu为带通滤波器；当wplwslwsswps为带阻滤波器。N，wc作为butter函数的调用参数。B,A=butter:b,a=butter(N,wc,high):设计N阶高通滤波器。b,a=butter(N,wc,low):设计N阶低通滤波器。b,a=butter(N,wc):当wc为具有两个元素的矢量wc=w1,w2时，它设计2N阶带通滤波器b,a=butter(N,wc,stop):若wc=w1,w2，则它设计2N阶带阻滤波器。利用冲激响应不变法，把系统函数为 （式1）模拟滤波器变换成等价的数字滤波器，采样间隔T=1S。先经过计算得到： （式2）则有如下式子 (式3)Matlab实验参考程序如下:B=1,1;A=1,5,6;T=1;Fs=1/T;Bz,Az=impinvar(B,A,Fs); %用冲激响应不变法将模拟滤波器变换成数字滤波器运行结果：Bz =1.0000 -0.2209Az = 1.0000 -0.1851 0.0067得到的数据和先前计算得到的数据相同，故利用冲激响应不变化法把模拟滤波器设计成数字滤波器正确。z=filter(B,A,x) (式4)输入X为滤波前序列，Y为滤波结果序列，B/A 提供滤波器系数，B为分子， A为分母。整个滤波过程是通过下面差分方程实现的： a(1)*y(n) = b(1)*x(n) + b(2)*x(n-1) + . + b(nb+1)*x(n-nb) - a(2)*y(n-1) - . - a(na+1)*y(n-na) 3.4总体方案系统的总体设计界面主要分为三个区域：播放区域、滤波器参数设置区域、滤波器类型选择区域。3.4.1播放区域包括播放和停止音乐的功能按键。3.4.2滤波器参数设置区域能够设置数字滤波器的各参数3.4.3滤波器类型选择区域在设置数字滤波器的参数之后，点击各类型滤波器按钮后弹出相应的波形图。4设计过程4.1系统流程图开始滤波器选择播放停止观察波形结束图1：系统流程图4.2具体设计（1）首先建立GUI界面，具体界面如下：图2 GUI界面建立（2）系统的总体设计界面主要分为四个区域：播放区域、滤波器参数设置区域、滤波器类型选择区域。具体界面如下图图3 GUI界面建立（3）播放区域设计包括播放、停止两个按钮，界面如下： 图4 播放按钮（4）滤波器参数设置区域包括，包括六个参数：wp(fp1) ws(fs1) rp rs fsu fpu区域界面如图所示:图5 参数设置按钮（5）滤波器类型选择区域包括高通、低通、带通、帯阻四个按钮，区域界面如下图所示。图6 选择按钮5.实验代码及结果5.1 MATLAB源程序（1）HIGH PASS FILTER 按钮所对应代码：function pushbutton1_Callback(hObject, eventdata, handles)global name1;global name2;global p;name1=D:WWWm2.wav;name2=D:WWWtu1.jpg; x,Fs=wavread(name1);h=axes(units,normalized,position,0,0,1,1);uistack(h,up);i=imread(name2);image(i);set(h,handlevisibility,off,visible,off);x1=x(:,1);N=length(x); f=Fs*(0:N/2-1)/N;figure(2);subplot(4,1,1);plot(x1);title(滤波前信号时域波形);X2k=abs(fft(x1,N);subplot(4,1,2);plot(f,X2k(1:N/2);title(滤波前信号频谱图);wp=2*str2num(get(handles.edit1,String)/Fs;ws=2*str2num(get(handles.edit2,String)/Fs;Rp=str2num(get(handles.edit3,String);As=str2num(get(handles.edit4,String);N,wc=buttord(wp,ws,Rp,As);%巴特沃斯滤波法B,A=butter(N,wc,high);%求模拟滤波器的两个参数Bz,Az=impinvar(B,A,Fs);%将模拟滤波器转换成数字滤波器w=pi/2:pi;Hk=freqz(Bz,Az,w); %求H（z）的频响wf=w*Fs/(2*pi); % 转化为Hzz=filter(B,A,x);subplot(4,1,3);plot(z);title(滤波后信号时域波形);Y1=abs(fft(z,Fs);subplot(4,1,4);plot(Y1(1:length(Y1)/2);title(滤波后信号的频谱); p=audioplayer(z,Fs);play(p); % hObject handle to pushbutton1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)（2）LOW PASS FILTER 按钮所对应代码：function pushbutton2_Callback(hObject, eventdata, handles)global name1;global name2;global p;name1=D:WWWm2.wav;name2=D:WWWtu1.jpg;x,Fs=wavread(name1);h=axes(units,normalized,position,0,0,1,1);uistack(h,up);i=imread(name2);image(i);set(h,handlevisibility,off,visible,off);x1=x(:,1);N=length(x); f=Fs*(0:N/2-1)/N;figure(2);subplot(4,1,1);plot(x1);title(滤波前信号时域波形);X2k=abs(fft(x1,N);subplot(4,1,2);plot(f,X2k(1:N/2);title(滤波前信号频谱图);wp=2*str2num(get(handles.edit1,String)/Fs;ws=2*str2num(get(handles.edit2,String)/Fs;Rp=str2num(get(handles.edit3,String);As=str2num(get(handles.edit4,String);N,wc=buttord(wp,ws,Rp,As);B,A=butter(N,wc,low);Bz,Az=impinvar(B,A,Fs);w=pi/2:pi;Hk=freqz(Bz,Az,w); %求H（z）的频响wf=w*Fs/(2*pi); % 转化为Hzz=filter(B,A,x);subplot(4,1,3);plot(z);title(滤波后信号时域波形);Y1=abs(fft(z,Fs);subplot(4,1,4);plot(Y1(1:length(Y1)/2);title(滤波后信号的频谱); p=audioplayer(z,Fs);play(p);(3) BAND PASS TILTER 按钮所对应代码function pushbutton3_Callback(hObject, eventdata, handles)global name1;global name2;global p; name1=D:WWWm2.wav;name2=D:WWWtu1.jpg;x,Fs=wavread(name1);h=axes(units,normalized,position,0,0,1,1);uistack(h,up);i=imread(name2);image(i);set(h,handlevisibility,off,visible,off);x1=x(:,1);N=length(x); f=Fs*(0:N/2-1)/N;figure(2);subplot(4,1,1);plot(x1);title(滤波前信号时域波形);X2k=abs(fft(x1,N);subplot(4,1,2);plot(f,X2k(1:N/2);title(滤波前信号频谱图);fsl=str2num(get(handles.edit2,String);fsu=str2num(get(handles.edit5,String);fpl=str2num(get(handles.edit1,String);fpu=str2num(get(handles.edit6,String);wp=2*fpl/Fs,2*fpu/Fs;ws=2*fsl/Fs,2*fsu/Fs;Rp=str2num(get(handles.edit3,String);As=str2num(get(handles.edit4,String);N,wc=buttord(wp,ws,Rp,As);B,A=butter(N,wc);Bz,Az=impinvar(B,A,Fs);w=pi/2:pi;Hk=freqz(Bz,Az,w); %求H（z）的频响wf=w*Fs/(2*pi); % 转化为Hzz=filter(B,A,x);subplot(4,1,3);plot(z);title(滤波后信号时域波开形);Y1=abs(fft(z,Fs);subplot(4,1,4);plot(Y1(1:length(Y1)/2);title(滤波后信号的频谱); p=audioplayer(z,Fs);play(p);（4）BAND STOP TILTER 按钮所对应代码function pushbutton4_Callback(hObject, eventdata, handles)global name1;global name2;global p;name1=D:WWWm2.wav;name2=D:WWWtu1.jpg;x,Fs=wavread(name1);h=axes(units,normalized,position,0,0,1,1);uistack(h,up);i=imread(name2);image(i);set(h,handlevisibility,off,visible,off);x1=x(:,1);N=length(x); f=Fs*(0:N/2-1)/N;figure(2);subplot(4,1,1);plot(x1);title(滤波前信号时域波形);X2k=abs(fft(x1,N);subplot(4,1,2);plot(f,X2k(1:N/2);title(滤波前信号频谱图);fsl=str2num(get(handles.edit2,String);fsu=str2num(get(handles.edit5,String);fpl=str2num(get(handles.edit1,String);fpu=str2num(get(handles.edit6,String);wp=2*fpl/Fs,2*fpu/Fs;ws=2*fsl/Fs,2*fsu/Fs;Rp=str2num(get(handles.edit3,String);As=str2num(get(handles.edit4,String);N,wc=buttord(wp,ws,Rp,As);B,A=butter(N,wc,stop);Bz,Az=impinvar(B,A,Fs);w=pi/2:pi;Hk=freqz(Bz,Az,w); %求H（z）的频响wf=w*Fs/(2*pi); % 转化为Hzz=filter(B,A,x);subplot(4,1,3);plot(z);title(滤波后信号时域波开形);Y1=abs(fft(z,Fs);subplot(4,1,4);plot(Y1(1:length(Y1)/2);title(滤波后信号的频谱); p=audioplayer(z,s);play(p);(5) PLAY按钮所对应代码function pushbutton5_Callback(hObject, eventdata, handles)global name1;global name2;global p;x,Fs=wavread(name1);h=axes(units,normalized,position,0,0,1,1);uistack(h,up);i=imread(name2);image(i);set(h,handlevisibility,off,visible,off);%全屏背景p=audioplayer(x,Fs);play(p);% hObject handle to pushbutton5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)(6) STOP 按钮所对应代码function pushbutton6_Callback(hObject, eventdata, handles)global p;stop(p);% hObject handle to pushbutton6 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)其他相关代码function varargout = projecttry(varargin)% PROJECTTRY M-file for projecttry.fig% PROJECTTRY, by itself, creates a new PROJECTTRY or raises the existing% singleton*.% H = PROJECTTRY returns the handle to a new PROJECTTRY or the handle to% the existing singleton*.% PROJECTTRY(CALLBACK,hObject,eventData,handles,.) calls the local% function named CALLBACK in PROJECTTRY.M with the given input arguments.% PROJECTTRY(Property,Value,.) creates a new PROJECTTRY or raises the% existing singleton*. Starting from the left, property value pairs are% applied to the GUI before projecttry_OpeningFcn gets called. An% unrecognized property name or invalid value makes property application% stop. All inputs are passed to projecttry_OpeningFcn via varargin.% *See GUI Options on GUIDEs Tools menu. Choose GUI allows only one% instance to run (singleton).% See also: GUIDE, GUIDATA, GUIHANDLES% Edit the above text to modify the response to help projecttry% Last Modified by GUIDE v2.5 21-May-2014 22:53:44% Begin initialization code - DO NOT EDITgui_Singleton = 1;gui_State = struct(gui_Name, mfilename, . gui_Singleton, gui_Singleton, . gui_OpeningFcn, projecttry_OpeningFcn, . gui_OutputFcn, projecttry_OutputFcn, . gui_LayoutFcn, , . gui_Callback, );if nargin & ischar(varargin1) gui_State.gui_Callback = str2func(varargin1);endif nargout varargout1:nargout = gui_mainfcn(gui_State, varargin:);else gui_mainfcn(gui_State, varargin:);end% End initialization code - DO NOT EDIT% - Executes just before projecttry is made visible.function projecttry_OpeningFcn(hObject, eventdata, handles, varargin)% This function has no output args, see OutputFcn.% hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% varargin command line arguments to projecttry (see VARARGIN)% Choose default command line output for projecttryhandles.output = hObject;% Update handles structureguidata(hObject, handles);% UIWAIT makes projecttry wait for user response (see UIRESUME)% uiwait(handles.figure1);% - Outputs from this function are returned to the command line.function varargout = projecttry_OutputFcn(hObject, eventdata, handles) % varargout cell array for returning output args (see VARARGOUT);% hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Get default command line output from handles structurevarargout1 = handles.output;function edit1_Callback(hObject, eventdata, handles)% hObject handle to edit1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,String) returns contents of edit1 as text% str2double(get(hObject,String) returns contents of edit1 as a double% - Executes during object creation, after setting all properties.function edit1_CreateFcn(hObject, eventdata, handles)% hObject handle to edit1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc & isequal(get(hObject,BackgroundColor), get(0,defaultUicontrolBackgroundColor) set(hObject,BackgroundColor,white);endfunction edit2_Callback(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,String) returns contents of edit2 as text% str2double(get(hObject,String) returns contents of edit2 as a double% - Executes during object creation, after setting all properties.function edit2_CreateFcn(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc & isequal(get(hObject,BackgroundColor), get(0,defaultUicontrolBackgroundColor) set(hObject,BackgroundColor,white);endfunction edit3_Callback(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,String) returns contents of edit3 as text% str2double(get(hObject,String) returns contents of edit3 as a double% - Executes during object creation, after setting all properties.function edit3_CreateFcn(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc & isequal(get(hObject,BackgroundColor), get(0,defaultUicontrolBackgroundColor) set(hObject,BackgroundColor,white);endfunction edit4_Callback(hObject, eventdata, handles)% hObject handle to edit4 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,String) returns contents of edit4 as text% str2double(get(hObject,String) returns contents of edit4 as a double% - Executes during object creation, after setting all properties.function edit4_CreateFcn(hObject, eventdata, handles)% hObject handle to edit4 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc & isequal(get(hObject,BackgroundColor), get(0,defaultUicontrolBackgroundColor) set(hObject,BackgroundColor,white);endfunction edit5_Callback(hObject, eventdata, handles)% hObject handle to edit5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,String) returns contents of edit5 as text% str2double(get(hObject,String) returns contents of edit5 as a double% - Executes during object creation, after setting all properties.function edit5_CreateFcn(hObject, eventdata, handles)% hObject handle to edit5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc & isequal(get(hObject,BackgroundColor), get(0,defaultUicontrolBackgroundColor) set(hObject,BackgroundColor,white);endfunction edit6_Callback(hObject, eventdata, handles)% hObject handle to edit6 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,String) returns contents of edit6 as text% str2double(get(hObject,String) returns contents of edit6 as a double% - Executes during object creation, after setting all properties.function edit6_CreateFcn(hObject, eventdata, handles)% hObject handle t