DTMF信号的产生与解码

课程设计的目的和任务“数字信号处理〞课程是信息和通信工程专业必修的专业技术根底课程。课程以信号与系统作为研究对象，研究对信号进行各种处理和利用的技术。通过该课程的学习，学生应牢固掌握确定性信号和系统的分析方法、相关算法、系统实现等的相关知识的，借助于数字滤波器的设计及实现，学生可掌握数字系统的分析以及设计方法。数字信号处理是理论性和工程性都很强的学科，本课程设计的目的就是使该课程的理论与工程应用的紧密结合,使学生深入理解信号处理的内涵和实质。本课程设计要求学生在理解信号处理的数学原理的根底上，应用计算机编程手段，实现一种信号分析或处理的设计，到达对所学内容融会贯穿，综合各局部知识，按照题目要求独立设计完成。课程设计的题目和要求1.课程设计题目：DTMF信号的产生与解码DTMF编解码广泛应用于数字拨号，简单通信协议等领域。目前所有的和机按键都是采用DTMF信号进行编码和传输的，该方案实际是利用模拟信号对数字符号进行编码。该编码方案共使用8个模拟频率对16个符号进行编码，这16个频率分为2个群：高音群和低音群。所以称为双音多频(Dual-ToneMultiple-Frequency)编码，其编码方案如图1。由图可知每个符号由一个高音频率和一个低音频率唯一确定。图1DTMF信号编码方案对于该信号的产生，我们可以利用数字振荡器来完成。而对这些信号的检测，那么可以利用DFT来完成。要注意的是，这里只需要计算16个频点的FFT输出，因此课本上介绍基2或基4算法并不是最优的，这时我们需要采用Goerzel算法完成所需的DFT。当然我们也可以用16个窄带带通滤波器完成，窄带带通滤波器的中心频率就是上述各频率。对窄带滤波器输出信号的输出做判决就可以得到解码的结果。编制程序生成并显示各符号的时域信号和对应的幅频曲线。编程模拟拨号过程：输入号码，生成各号码的时域信号，给时域信号加噪声，编程对含噪声的拨号信号进行解码。编制程序测试编解码程序的正确性。要列出表格，统计拨出的符号的解码成功率。独立完成设计，选择自己熟悉的编程语言编写程序，最好能给出图形界面。设计过程与结果1.在MATLAB中建立一个GUI图形界面，将本课程设计所要实现的功能的一些工具拖进GUI界面，并根据需要修改各个工具的属性，建立的初始界面如图2所示。图2GUI图形设计的初始界面翻开jink.fig界面所对应的源程序编辑窗口，其中MATLAB会自动生成界面的初始化程序代码以及1——D、“解码检测〞和“退出〞共18个按钮各按钮的函数名和参数功能解释。在这里，我们需要对每个按钮要实现的具体功能编写程序，由于按钮函数较多，且1——D数字按钮的功能相似，故可以编写函数供每个这样的函数调用，从而防止程序的繁杂冗余。例如对于点击数字键“1〞时要实现的功能的函数可以为如下代码：set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'1');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'1');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);当运行程序后点击数字键“1〞时，pushbutton1_Callback函数会调用PressKeyDown函数，从而完成发出相应的声音、在text1文本框中显示出点击的数字、在axes1和axes2画出对应的图形等功能。点击几个数字或字母键后，在界面中运行的结果如图3所示。图3拨号时界面的显示结果在拨号后，要对所接收的拨号信号进行解码检测，检测两个正弦波的频率分别是多少，以判断所对应的十进制数字或字母符号。检测方法有两种，一是用一组滤波器提取所关心的频率，根据两个滤波器的输出信号判断相应的数字或符号，另一是用DFT〔FFT〕对双音多频信号进行频谱分析，由信号幅度谱判断信号的两个频率，最后确定相应的数字或符号。本设计所编写的相应的解码局部程序代码如下：functionpushbutton17_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton17(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)handles.DecodeTelNumber='';%清空解码字符串变量，开始新一轮解码。keys=['1','2','3','A';'4','5','6','B';'7','8','9','C';'*','0','#','D'];fori=1:length(handles.TelNumber)Signal=dtmf(handles.TelNumber(i));RowNumber=FindLowerFreq(Signal);ColumnNumber=FindHigherFreq(Signal);ResultKey=keys(RowNumber,ColumnNumber);handles.DecodeTelNumber=strcat(handles.DecodeTelNumber,ResultKey);set(handles.DecodeText,'string',handles.DecodeTelNumber);endhandles.TelNumber='';%解码完成后，拨号变量清空，方便下一次拨号。点击“解码检测〞按钮，进行解码的运行结果如图4所示。图4解码后的结果由图4可以看出，在解码的文本框中显示出正确的拨号，表示解码正确。点“退出〞键后界面关闭退出。课程设计总结经过几天的努力，我终于完成了基于MATLAB的DTMF信号的产生与解码课程设计，由于刚上完数字信号处理这门课程，对相关的知识还是比拟熟悉，但是对于数字信号处理的实质的理解还是不够深刻，因此刚开始不知如何下手，觉得困难比拟多，不过最后经过屡次修改和整理，还是完成了。受到自己知识水平的限制，此次课程设计还有很多缺乏的地方。通过这次课程设计，我发现自己以前关于数字信号处理这门课的看法太片面，课程设计不仅仅是对所学知识的一种检验，更是对自己能力的一种提高，这次课程设计使我明白前面所学的那点知识是非常欠缺的，要学的东西还很多。比方在使用MATLAB制作图形界面上，以前上过这个课程，但没有学其中GUI界面设计局部，这就要求我们去自学。在这次课程设计中，我遇到过很多问题，发现我所学的知识实在有限，好在同学之间可以相互讨论，还可以充分利用网络去查阅相关资料。在整理与修改的过程中，我学到了很多新的知识，也培养了独立思考和设计的能力，树立了对知识应用的信心，相信会对以后的学习工作都有很大的帮助，并且提高了自己的动手实践能力。在这次课程设计的过程中，我得到了许多人的帮助，感谢指导老师耐心的讲解，也感谢在一起讨论的同学，从中我得到了很多好的建议和方法。总之，本次课程设计的过程虽然曲折，但是收获还是蛮大的，这不是对知识的终结，而是我学习更多知识的一个平台。参考文献李正周，MATLAB数字信号处理与应用，北京：清华大学出版社，2023徐明远、刘增力，MATLAB仿真在信号处理中的应用，西安：电子科技大学出版社，2007李显宏，MTALAB7.x界面设计与编译技巧，北京：电子工业出版社，2006附录源程序代码：functionvarargout=jink(varargin)%JINK,byitself,createsanewJINKorraisestheexisting%singleton*.%%H=JINKreturnsthehandletoanewJINKorthehandleto%theexistingsingleton*.%%JINK('CALLBACK',hObject,eventData,handles,...)callsthelocal%functionnamedCALLBACKinJINK.Mwiththegiveninputarguments.%%JINK('Property','Value',...)createsanewJINKorraisesthe%existingsingleton*.Startingfromtheleft,propertyvaluepairsare%appliedtotheGUIbeforejink_OpeningFcngetscalled.An%unrecognizedpropertynameorinvalidvaluemakespropertyapplication%stop.Allinputsarepassedtojink_OpeningFcnviavarargin.%%*SeeGUIOptionsonGUIDE'sToolsmenu.Choose"GUIallowsonlyone%instancetorun(singleton)".%%Seealso:GUIDE,GUIDATA,GUIHANDLES%Edittheabovetexttomodifytheresponsetohelpjink%LastModifiedbyGUIDEv2.501-Jan-202313:20:27%Begininitializationcode-DONOTEDITgui_Singleton=1;gui_State=struct('gui_Name',mfilename,...'gui_Singleton',gui_Singleton,...'gui_OpeningFcn',@jink_OpeningFcn,...'gui_OutputFcn',@jink_OutputFcn,...'gui_LayoutFcn',[],...'gui_Callback',[]);ifnargin&&ischar(varargin{1})gui_State.gui_Callback=str2func(varargin{1});endifnargout[varargout{1:nargout}]=gui_mainfcn(gui_State,varargin{:});elsegui_mainfcn(gui_State,varargin{:});end%Endinitializationcode-DONOTEDIT%---Executesjustbeforejinkismadevisible.functionjink_OpeningFcn(hObject,eventdata,handles,varargin)%Thisfunctionhasnooutputargs,seeOutputFcn.%hObjecthandletofigure%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)%varargincommandlineargumentstojink(seeVARARGIN)%Choosedefaultcommandlineoutputforjinkhandles.output=hObject;handles.DTMFSignal=[];handles.TelNumber='';handles.DecodeTelNumber='';%保存解码字符串变量set(gcf,'CurrentAxes',handles.axes1);xlabel('单位：〔s〕');set(gcf,'CurrentAxes',handles.axes2);xlabel('单位：〔Hz〕');%Updatehandlesstructureguidata(hObject,handles);%UIWAITmakesjinkwaitforuserresponse(seeUIRESUME)%uiwait(handles.figure1);%---Outputsfromthisfunctionarereturnedtothecommandline.functionvarargout=jink_OutputFcn(hObject,eventdata,handles)%varargoutcellarrayforreturningoutputargs(seeVARARGOUT);%hObjecthandletofigure%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)%Getdefaultcommandlineoutputfromhandlesstructurevarargout{1}=handles.output;%---Executesonbuttonpressinpushbutton1.functionpushbutton1_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton1(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'1');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'1');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton2.functionpushbutton2_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton2(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'2');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'2');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton3.functionpushbutton3_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton3(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'3');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'3');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton4.functionpushbutton4_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton4(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'4');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'4');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton5.functionpushbutton5_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton5(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'5');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'5');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton6.functionpushbutton6_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton6(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'6');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'6');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton7.functionpushbutton7_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton7(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'7');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'7');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton8.functionpushbutton8_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton8(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'8');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'8');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton9.functionpushbutton9_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton9(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'9');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'9');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton10.functionpushbutton10_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton10(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'*');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'*');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton11.functionpushbutton11_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton11(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'0');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'0');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton12.functionpushbutton12_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton12(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'#');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'#');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton13.functionpushbutton13_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton13(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'A');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'A');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton14.functionpushbutton14_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton14(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'B');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'B');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton15.functionpushbutton15_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton15(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'C');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'C');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton16.functionpushbutton16_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton16(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)set(handles.DecodeText,'string','');%清空解码显示文本框Signal=PressKeyDown(handles,'D');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'D');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);%---Executesonbuttonpressinpushbutton17.functionpushbutton17_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton17(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)handles.DecodeTelNumber='';%清空解码字符串变量，开始新一轮解码。keys=['1','2','3','A';'4','5','6','B';'7','8','9','C';'*','0','#','D'];fori=1:length(handles.TelNumber)Signal=dtmf(handles.TelNumber(i));RowNumber=FindLowerFreq(Signal);ColumnNumber=FindHigherFreq(Signal);ResultKey=keys(RowNumber,ColumnNumber);handles.DecodeTelNumber=strcat(handles.DecodeTelNumber,ResultKey);set(handles.DecodeText,'string',handles.DecodeTelNumber);endhandles.TelNumber='';%解码完成后，拨号变量清空，方便下一次拨号。%Updatehandlesstructureguidata(hObject,handles);%RowNumber=FindLowerFreq(handles.DTMFSignal);%ColumnNumber=FindHigherFreq(handles.DTMFSignal);%ResultKey=keys(RowNumber,ColumnNumber);%set(handles.DecodeText,'string',char(ResultKey));functionSignal=PressKeyDown(handles,key)Signal=dtmf(key);sound(Signal,8000);%利用声卡播放拨号音set(gcf,'CurrentAxes',handles.axes1);NSignal=length(Signal);t=1/8000:1/8000:NSignal/8000;plot(t,Signal);grid;%画信号的时域波形xlabel('单位：〔s〕');Spectrum=fft(Signal);Spectrum=fftshift(Spectrum);%计算信号的频谱N=length(Spectrum);nStep=(2*pi)/(N-1);w=-pi:nStep:pi;set(gcf,'CurrentAxes',handles.axes2);plot(w/(2*pi)*8000,abs(Spectrum));grid;%画信号的频谱图axis([-2000,2000,0,200]);xlabel('单位：〔Hz〕');functionx=dtmf(key);fs=8000;N=0.1*fs;%信号时间为100ms,N=Tpmin*Fs；Tpmin根据频率分辨率得到，DTMF信号的最小频率间隔为73HZ,故至少需要110点R=1;fl=0;fh=0;n=0:100;switchkeycase{'1','2','3','A'}fl=697;case{'4','5','6','B'}fl=770;case{'7','8','9','C'}fl=852;case{'*','0','#','D'}fl=941;endswitchkeycase{'1','4','7','*'}fh=1209;case{'2','5','8','0'}fh=1336;case{'3','6','9','#'}fh=1477;case{'A','B','C','D'}fh=1633;