课题一数字信号处理系统设计一、项目要求用本课程所学的数字信号处理理论知识，设计一个具有信号的采集、处理、传输、显示和存储等功能的系统，内容如下：１、录制一段语音信号，并对录制的语音信号进行采样（采样频率可取fs=22050Hz）;２、画出采样后的语音信号的时域波形和频谱图；３、滤波器的性能指标：低通滤波器：通带边界频率ｆｐ＝１ｋＨｚ，通带最大衰减Ａｐ＝１ｄB；阻带边界频率ｆｐ＝１.2ｋＨｚ，阻带最小衰减Ａｐ＝１00ｄB；高通滤波器：通带边界频率ｆｐ＝5ｋＨｚ，通带最大衰减Ａｐ＝１ｄB；阻带边界频率ｆｐ＝4.8ｋＨｚ，阻带最小衰减Ａｐ＝１00ｄB；带通滤波器：通带上限截止频率fp2=3kHz, 通带下限截止频率fp1=1.2kHz;阻带上限截止频率fs2=3.2kHz, 通带下限截止频率fp1=1kHz;通带最大衰减Ap=1dB, 阻带最小衰减As=100dB;采用双线性变换法设计滤波器，并画出滤波器的频率响应；４、用自己设计的滤波器对采样的信号进行滤波，画出滤波后信号的时域波形和频谱图，并对滤波前后的信号进行对比，分析信号的变化；５、回放语音６、用ＧＵＩ设计一个信号系统的用户界面。
二、实验所要用到的ＭＡＴＬＡＢ函数１、语音信号的采样与播放wavread();[y，fs，bite]=wavread（）；%语音信号的采样sound（y，fs，bite）；%播放语音2.滤波器：IIR：butte（）；%巴特沃思滤波器cheby1(); %切比雪夫I滤波器elliptical（）；%椭圆滤波器3.频率响应：[h，f]=freqz（b,a,n,fs）freqz(b,a,n,fs)5.快速傅里叶变换fft (x, n)6.画曲线plot(x, y)stem(x, y)7.在MATLAB中，设计辅助低通原型巴特沃思和切比雪夫滤波器的阶数和截止频率；1）利用buttord和cheblord确定阶数；2）[num，den]=butter（N，Wn），[num，den]=cheby1（N，Wn）3）lp2hp,lp2bp,lp2bs可以完成低通滤波器到高通，带通，带阻的转换4）使用biliner对模拟滤波器进行双线性变换，求得数字滤波器的传输函数系数三、数字滤波器（代码）1.IIR低通滤波器fp=1000;ft=5500;fs=1200;wp=2*pi*fp/ft;ws=2*pi*fs/ft;Fp=2*ft*tan(wp/2);Fs=2*ft*tan(ws/2);[n,Omgc]=buttord(Fp,Fs,1,100,'s');[z,p,k]=buttap(n);B=k*real(poly(z));A=real(poly(p));[b1,a1]=lp2lp(B,A,Omgc);[ba1,aa1]=bilinear(b1,a1,ft); %模拟转数字[Ha,w]=freqz(ba1,aa1); %求频率相应plot(w*ft/(2*pi),20*log10(abs(Ha)));title('IIR 低通滤波器');xlabel('频率/HZ');ylabel('幅值');2.IIR高通滤波器fp=5000;ft=25000;%取抽样频率•fs=4800;Rp=1;As=100;wp=2*pi*fp/ft;%通带频率ws=2*pi*fs/ft;%截止频率Fp=2*ft*tan(wp/2);Fs=2*ft*tan(ws/2);[n,Omgc]=ellipord(Fp,Fs,Rp,As,'s'); %计算阶数n和截止频率[z,p,k]=ellipap(n,Rp,As);B3=k*real(poly(z));A3=real(poly(p));[b3,a3]=lp2hp(B3,A3,Omgc);[ba3,aa3]=bilinear(b3,a3,ft);[Ha,w]=freqz(ba3,aa3);plot(w*ft/(2*pi),20*log10(abs(Ha)));title('IIR高通滤波器');xlabel('频率/HZ');ylabel('幅值');3.IIR带通滤波器fp1=1200;fp2=3000;fs1=1000;fs2=3200;ft=10000; As=100;Rp=1;wp1=2*pi*fp1/ft;wp2=2*pi*fp2/ft;ws1=2*pi*fs1/ft;ws2=2*pi*fs2/ft;Fp1=2*ft*tan(wp1/2);Fp2=2*ft*tan(wp2/2);Fp=[Fp1,Fp2];Fs1=2*ft*tan(ws1/2);Fs2=2*ft*tan(ws2/2);Fs=[Fs1,Fs2];bw=Fp2-Fp1;w0=sqrt(Fp1*Fp2);%通带宽和中心频率[n,Omgn]=cheb1ord(Fp,Fs,Rp,As,'s');[z,p,k]=cheb1ap(n,Rp);B2=k*real(poly(z));A2=real(poly(p));[b2,a2]=lp2bp(B2,A2,w0,bw);[ba2,aa2]=bilinear(b2,a2,ft);[Ha,w]=freqz(ba2,aa2);plot(w*ft/(2*pi),20*log10(abs(Ha)));title('IIR 带通滤波器'); xlabel('频率/HZ'); ylabel('幅值');四、总代码function varargout = bzh(varargin)% BZH M-file for bzh.fig% BZH, by itself, creates a new BZH or raises the existing% singleton*.%% H = BZH returns the handle to a new BZH or the handle to% the existing singleton*.%% BZH('CALLBACK',hObject,eventData,handles,...) calls the local% function named CALLBACK in BZH.M with the given input arguments.%% BZH('Property','Value',...) creates a new BZH or raises the % existing singleton*. Starting from the left, property value pairs are% applied to the GUI before ko_OpeningFunction gets called. An % unrecognized property name or invalid value makes property application% stop. All inputs are passed to bzh_OpeningFcn via varargin. %% *See GUI Options on GUIDE's Tools menu. Choose "GUI allowsonly one% instance to run (singleton)".%% See also: GUIDE, GUIDATA, GUIHANDLES% Copyright 2002-2003 The MathWorks, Inc.% Edit the above text to modify the response to help bzh% Last Modified by GUIDE v2.5 09-Jan-2014 08:54:22% Begin initialization code - DO NOT EDITgui_Singleton = 1;gui_State = struct('gui_Name', mfilename, ...'gui_Singleton', gui_Singleton, ...'gui_OpeningFcn', @bzh_OpeningFcn, ...'gui_OutputFcn', @bzh_OutputFcn, ...'gui_LayoutFcn', [] , ...'gui_Callback', []);if nargin && ischar(varargin{1})gui_State.gui_Callback = str2func(varargin{1});endif nargout[varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:}); elsegui_mainfcn(gui_State, varargin{:});end% End initialization code - DO NOT EDIT% --- Executes just before bzh is made visible.function bzh_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 bzh (see VARARGIN)% Choose default command line output for bzhhandles.output = hObject;% Update handles structureguidata(hObject, handles);% UIWAIT makes bzh wait for user response (see UIRESUME)% uiwait(handles.figure1);% --- Outputs from this function are returned to the command line. function varargout = bzh_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 structurevarargout{1} = handles.output;% --- Executes on button press in tag_start.function tag_start_Callback(hObject, eventdata, handles)% hObject handle to tag_start (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) axes(handles.axes1)cla;global z0;global yy;fs=22050;nbits=32;[yy,fs,nbits]=wavread('D:\f.wav'); %语音信号加载sound(yy,fs); %回放语音z0=yy;axes(handles.axes1);plot(yy);title('时域采样信号波形');grid onn=length(yy); %求出语音信号的长度Y=fft(yy,n); %傅里叶变换axes(handles.axes2);plot(20*log10(abs(Y)));title('时域采样信号频谱');guidata(hObject,handles);grid on% --- Executes on button press in tag_ditong.function tag_ditong_Callback(hObject, eventdata, handles)% hObject handle to tag_ditong (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) axes(handles.axes1)cla;global z1;global yy;global ba1;global aa1;global Fp;global Fs;fp=1000;ft=5500;fs=1200;wp=2*pi*fp/ft;ws=2*pi*fs/ft;Fp=2*ft*tan(wp/2);Fs=2*ft*tan(ws/2);[n,Omgc]=buttord(Fp,Fs,1,100,'s');[z,p,k]=buttap(n);B=k*real(poly(z));A=real(poly(p));[b1,a1]=lp2lp(B,A,Omgc);[ba1,aa1]=bilinear(b1,a1,ft); %模拟转数字z1=filter(ba1,aa1,yy);[Ha,w]=freqz(ba1,aa1); %求频率相应plot(w*ft/(2*pi),20*log10(abs(Ha)));title('IIR 低通滤波器');xlabel('频率/HZ');ylabel('幅值');% --- Executes on button press in tag_gaotong.function tag_gaotong_Callback(hObject, eventdata, handles)% hObject handle to tag_gaotong (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) axes(handles.axes2)cla;global yy;global z2;global B3;global ba3;global aa3;global Fp;global Fs;fp=5000;ft=25000;%取抽样频率•fs=4800;Rp=1;As=100;wp=2*pi*fp/ft;%通带频率ws=2*pi*fs/ft;%截止频率Fp=2*ft*tan(wp/2);Fs=2*ft*tan(ws/2);[n,Omgc]=ellipord(Fp,Fs,Rp,As,'s'); %计算阶数n和截止频率[z,p,k]=ellipap(n,Rp,As);B3=k*real(poly(z));A3=real(poly(p));[b3,a3]=lp2hp(B3,A3,Omgc);[ba3,aa3]=bilinear(b3,a3,ft);z2=filter(ba3,aa3,yy);[Ha,w]=freqz(ba3,aa3);plot(w*ft/(2*pi),20*log10(abs(Ha)));title('IIR高通滤波器');xlabel('频率/HZ');ylabel('幅值');% --- Executes on button press in tag_daitong.function tag_daitong_Callback(hObject, eventdata, handles)% hObject handle to tag_daitong (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) axes(handles.axes3)cla;global yy;global z3;global B2;global ba2;global aa2;fp1=1200;fp2=3000;fs1=1000;fs2=3200;ft=10000;As=100;Rp=1;wp1=2*pi*fp1/ft;wp2=2*pi*fp2/ft;ws1=2*pi*fs1/ft;ws2=2*pi*fs2/ft;Fp1=2*ft*tan(wp1/2);Fp2=2*ft*tan(wp2/2);Fp=[Fp1,Fp2];Fs1=2*ft*tan(ws1/2);Fs2=2*ft*tan(ws2/2);Fs=[Fs1,Fs2];bw=Fp2-Fp1;w0=sqrt(Fp1*Fp2);%通带宽和中心频率[n,Omgn]=cheb1ord(Fp,Fs,Rp,As,'s');[z,p,k]=cheb1ap(n,Rp);B2=k*real(poly(z));A2=real(poly(p));[b2,a2]=lp2bp(B2,A2,w0,bw);[ba2,aa2]=bilinear(b2,a2,ft);z3=filter(ba2,aa2,yy);[Ha,w]=freqz(ba2,aa2);plot(w*ft/(2*pi),20*log10(abs(Ha)));title('IIR 带通滤波器');xlabel('频率/HZ');ylabel('幅值');% --- Executes on button press in tag_dibo.function tag_dibo_Callback(hObject, eventdata, handles)% hObject handle to tag_dibo (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) axes(handles.axes3)cla;global yy;global z1;global ba1;global aa1;m4=fft(z1);plot(z1,'y');title('IIR滤波后的信号波形');xlabel('时间/t');ylabel('幅值');axes(handles.axes4)cla;plot(abs(m4),'y');title('IIR滤波后信号频谱');xlabel('频率/HZ');ylabel('幅值');% --- Executes on button press in tag_gaobo.function tag_gaobo_Callback(hObject, eventdata, handles)% hObject handle to tag_gaobo (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) axes(handles.axes3)cla;global yy;global z2;global B3;global ba3;global aa3;m5=fft(z2);plot(z2,'y');title('IIR滤波后的信号波形');xlabel('时间/t');ylabel('幅值');axes(handles.axes4)cla;plot(abs(m5),'y');title('IIR滤波后信号频谱');xlabel('频率/HZ');ylabel('幅值');% --- Executes on button press in tag_daibo.function tag_daibo_Callback(hObject, eventdata, handles)% hObject handle to tag_daibo (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) axes(handles.axes3)cla;global yy;global z3;global B2;global ba2;global aa2;m6=fft(z3);plot(z3,'y');title('IIR滤波后的信号波形');xlabel('时间/t');ylabel('幅值');axes(handles.axes4)cla;plot(abs(m6),'y');title('IIR滤波后信号频谱');xlabel('频率/HZ');ylabel('幅值');% --- Executes on selection change in tag_choose.function tag_choose_Callback(hObject, eventdata, handles)% hObject handle to tag_choose (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)% Hints: contents = get(hObject,'String') returns tag_choose contents as cell array% contents{get(hObject,'Value')} returns selected item from tag_choose% --- Executes during object creation, after setting all properties. function tag_choose_CreateFcn(hObject, eventdata, handles)% hObject handle to tag_choose (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles empty - handles not created until after all CreateFcns called% Hint: popupmenu controls usually have a white background on Windows. % See ISPC and COMPUTER.if ispcset(hObject,'BackgroundColor','white');elseset(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundCo lor'));end% --- Executes on button press in tag_return.function tag_return_Callback(hObject, eventdata, handles)% hObject handle to tag_return (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) global z0;global z1;global z2;global z3;global yy;val=get(handles.tag_choose,'Value');if(val==1)[yy,fs,nbits]=wavread('D:\f.wav'); %语音信号加载sound(yy,fs); %回放语音endif(val==2)sound(z1,22050);endif(val==3)sound(z3,22050);endif(val==4)sound(z2,22050);end% --- Executes on mouse press over axes background.function axes1_ButtonDownFcn(hObject, eventdata, handles)% hObject handle to axes1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)% --- If Enable == 'on', executes on mouse press in 5 pixel border. % --- Otherwise, executes on mouse press in 5 pixel border or over tag_start.function tag_start_ButtonDownFcn(hObject, eventdata, handles)% hObject handle to tag_start (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)采样后信号滤波器数字波形IIR低通滤波后波形图IIR高通滤波后波形图IIR带通滤波后波形图。
