課程設(shè)計(jì)的目的和任務(wù)“數(shù)字信號(hào)處理〞課程是信息和通信工程專業(yè)必修的專業(yè)技術(shù)根底課程。課程以信號(hào)與系統(tǒng)作為研究對(duì)象，研究對(duì)信號(hào)進(jìn)行各種處理和利用的技術(shù)。通過(guò)該課程的學(xué)習(xí)，學(xué)生應(yīng)牢固掌握確定性信號(hào)和系統(tǒng)的分析方法、相關(guān)算法、系統(tǒng)實(shí)現(xiàn)等的相關(guān)知識(shí)的，借助于數(shù)字濾波器的設(shè)計(jì)及實(shí)現(xiàn)，學(xué)生可掌握數(shù)字系統(tǒng)的分析以及設(shè)計(jì)方法。數(shù)字信號(hào)處理是理論性和工程性都很強(qiáng)的學(xué)科，本課程設(shè)計(jì)的目的就是使該課程的理論與工程應(yīng)用的緊密結(jié)合,使學(xué)生深入理解信號(hào)處理的內(nèi)涵和實(shí)質(zhì)。本課程設(shè)計(jì)要求學(xué)生在理解信號(hào)處理的數(shù)學(xué)原理的根底上，應(yīng)用計(jì)算機(jī)編程手段，實(shí)現(xiàn)一種信號(hào)分析或處理的設(shè)計(jì)，到達(dá)對(duì)所學(xué)內(nèi)容融會(huì)貫穿，綜合各局部知識(shí)，按照題目要求獨(dú)立設(shè)計(jì)完成。課程設(shè)計(jì)的題目和要求1.課程設(shè)計(jì)題目：DTMF信號(hào)的產(chǎn)生與解碼DTMF編解碼廣泛應(yīng)用于數(shù)字撥號(hào)，簡(jiǎn)單通信協(xié)議等領(lǐng)域。目前所有的和機(jī)按鍵都是采用DTMF信號(hào)進(jìn)行編碼和傳輸?shù)?，該方案?shí)際是利用模擬信號(hào)對(duì)數(shù)字符號(hào)進(jìn)行編碼。該編碼方案共使用8個(gè)模擬頻率對(duì)16個(gè)符號(hào)進(jìn)行編碼，這16個(gè)頻率分為2個(gè)群：高音群和低音群。所以稱為雙音多頻(Dual-ToneMultiple-Frequency)編碼，其編碼方案如圖1。由圖可知每個(gè)符號(hào)由一個(gè)高音頻率和一個(gè)低音頻率唯一確定。圖1DTMF信號(hào)編碼方案對(duì)于該信號(hào)的產(chǎn)生，我們可以利用數(shù)字振蕩器來(lái)完成。而對(duì)這些信號(hào)的檢測(cè)，那么可以利用DFT來(lái)完成。要注意的是，這里只需要計(jì)算16個(gè)頻點(diǎn)的FFT輸出，因此課本上介紹基2或基4算法并不是最優(yōu)的，這時(shí)我們需要采用Goerzel算法完成所需的DFT。當(dāng)然我們也可以用16個(gè)窄帶帶通濾波器完成，窄帶帶通濾波器的中心頻率就是上述各頻率。對(duì)窄帶濾波器輸出信號(hào)的輸出做判決就可以得到解碼的結(jié)果。編制程序生成并顯示各符號(hào)的時(shí)域信號(hào)和對(duì)應(yīng)的幅頻曲線。編程模擬撥號(hào)過(guò)程：輸入號(hào)碼，生成各號(hào)碼的時(shí)域信號(hào)，給時(shí)域信號(hào)加噪聲，編程對(duì)含噪聲的撥號(hào)信號(hào)進(jìn)行解碼。編制程序測(cè)試編解碼程序的正確性。要列出表格，統(tǒng)計(jì)撥出的符號(hào)的解碼成功率。獨(dú)立完成設(shè)計(jì)，選擇自己熟悉的編程語(yǔ)言編寫程序，最好能給出圖形界面。設(shè)計(jì)過(guò)程與結(jié)果1.在MATLAB中建立一個(gè)GUI圖形界面，將本課程設(shè)計(jì)所要實(shí)現(xiàn)的功能的一些工具拖進(jìn)GUI界面，并根據(jù)需要修改各個(gè)工具的屬性，建立的初始界面如圖2所示。圖2GUI圖形設(shè)計(jì)的初始界面翻開jink.fig界面所對(duì)應(yīng)的源程序編輯窗口，其中MATLAB會(huì)自動(dòng)生成界面的初始化程序代碼以及1——D、“解碼檢測(cè)〞和“退出〞共18個(gè)按鈕各按鈕的函數(shù)名和參數(shù)功能解釋。在這里，我們需要對(duì)每個(gè)按鈕要實(shí)現(xiàn)的具體功能編寫程序，由于按鈕函數(shù)較多，且1——D數(shù)字按鈕的功能相似，故可以編寫函數(shù)供每個(gè)這樣的函數(shù)調(diào)用，從而防止程序的繁雜冗余。例如對(duì)于點(diǎn)擊數(shù)字鍵“1〞時(shí)要實(shí)現(xiàn)的功能的函數(shù)可以為如下代碼：set(handles.DecodeText,'string','');%清空解碼顯示文本框Signal=PressKeyDown(handles,'1');handles.DTMFSignal=Signal;handles.TelNumber=strcat(handles.TelNumber,'1');%Updatehandlesstructureguidata(hObject,handles);set(handles.CodeText,'string',handles.TelNumber);當(dāng)運(yùn)行程序后點(diǎn)擊數(shù)字鍵“1〞時(shí)，pushbutton1_Callback函數(shù)會(huì)調(diào)用PressKeyDown函數(shù)，從而完成發(fā)出相應(yīng)的聲音、在text1文本框中顯示出點(diǎn)擊的數(shù)字、在axes1和axes2畫出對(duì)應(yīng)的圖形等功能。點(diǎn)擊幾個(gè)數(shù)字或字母鍵后，在界面中運(yùn)行的結(jié)果如圖3所示。圖3撥號(hào)時(shí)界面的顯示結(jié)果在撥號(hào)后，要對(duì)所接收的撥號(hào)信號(hào)進(jìn)行解碼檢測(cè)，檢測(cè)兩個(gè)正弦波的頻率分別是多少，以判斷所對(duì)應(yīng)的十進(jìn)制數(shù)字或字母符號(hào)。檢測(cè)方法有兩種，一是用一組濾波器提取所關(guān)心的頻率，根據(jù)兩個(gè)濾波器的輸出信號(hào)判斷相應(yīng)的數(shù)字或符號(hào)，另一是用DFT〔FFT〕對(duì)雙音多頻信號(hào)進(jìn)行頻譜分析，由信號(hào)幅度譜判斷信號(hào)的兩個(gè)頻率，最后確定相應(yīng)的數(shù)字或符號(hào)。本設(shè)計(jì)所編寫的相應(yīng)的解碼局部程序代碼如下：functionpushbutton17_Callback(hObject,eventdata,handles)%hObjecthandletopushbutton17(seeGCBO)%eventdatareserved-tobedefinedinafutureversionofMATLAB%handlesstructurewithhandlesanduserdata(seeGUIDATA)handles.DecodeTelNumber='';%清空解碼字符串變量，開始新一輪解碼。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='';%解碼完成后，撥號(hào)變量清空，方便下一次撥號(hào)。點(diǎn)擊“解碼檢測(cè)〞按鈕，進(jìn)行解碼的運(yùn)行結(jié)果如圖4所示。圖4解碼后的結(jié)果由圖4可以看出，在解碼的文本框中顯示出正確的撥號(hào)，表示解碼正確。點(diǎn)“退出〞鍵后界面關(guān)閉退出。課程設(shè)計(jì)總結(jié)經(jīng)過(guò)幾天的努力，我終于完成了基于MATLAB的DTMF信號(hào)的產(chǎn)生與解碼課程設(shè)計(jì)，由于剛上完數(shù)字信號(hào)處理這門課程，對(duì)相關(guān)的知識(shí)還是比擬熟悉，但是對(duì)于數(shù)字信號(hào)處理的實(shí)質(zhì)的理解還是不夠深刻，因此剛開始不知如何下手，覺(jué)得困難比擬多，不過(guò)最后經(jīng)過(guò)屢次修改和整理，還是完成了。受到自己知識(shí)水平的限制，此次課程設(shè)計(jì)還有很多缺乏的地方。通過(guò)這次課程設(shè)計(jì)，我發(fā)現(xiàn)自己以前關(guān)于數(shù)字信號(hào)處理這門課的看法太片面，課程設(shè)計(jì)不僅僅是對(duì)所學(xué)知識(shí)的一種檢驗(yàn)，更是對(duì)自己能力的一種提高，這次課程設(shè)計(jì)使我明白前面所學(xué)的那點(diǎn)知識(shí)是非常欠缺的，要學(xué)的東西還很多。比方在使用MATLAB制作圖形界面上，以前上過(guò)這個(gè)課程，但沒(méi)有學(xué)其中GUI界面設(shè)計(jì)局部，這就要求我們?nèi)プ詫W(xué)。在這次課程設(shè)計(jì)中，我遇到過(guò)很多問(wèn)題，發(fā)現(xiàn)我所學(xué)的知識(shí)實(shí)在有限，好在同學(xué)之間可以相互討論，還可以充分利用網(wǎng)絡(luò)去查閱相關(guān)資料。在整理與修改的過(guò)程中，我學(xué)到了很多新的知識(shí)，也培養(yǎng)了獨(dú)立思考和設(shè)計(jì)的能力，樹立了對(duì)知識(shí)應(yīng)用的信心，相信會(huì)對(duì)以后的學(xué)習(xí)工作都有很大的幫助，并且提高了自己的動(dòng)手實(shí)踐能力。在這次課程設(shè)計(jì)的過(guò)程中，我得到了許多人的幫助，感謝指導(dǎo)老師耐心的講解，也感謝在一起討論的同學(xué)，從中我得到了很多好的建議和方法?？傊?，本次課程設(shè)計(jì)的過(guò)程雖然曲折，但是收獲還是蠻大的，這不是對(duì)知識(shí)的終結(jié)，而是我學(xué)習(xí)更多知識(shí)的一個(gè)平臺(tái)。參考文獻(xiàn)李正周，MATLAB數(shù)字信號(hào)處理與應(yīng)用，北京：清華大學(xué)出版社，2023徐明遠(yuǎn)、劉增力，MATLAB仿真在信號(hào)處理中的應(yīng)用，西安：電子科技大學(xué)出版社，2007李顯宏，MTALAB7.x界面設(shè)計(jì)與編譯技巧，北京：電子工業(yè)出版社，2006附錄源程序代碼：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='';%保存解碼字符串變量set(gcf,'CurrentAxes',handles.axes1);xlabel('單位：〔s〕');set(gcf,'CurrentAxes',handles.axes2);xlabel('單位：〔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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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','');%清空解碼顯示文本框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='';%清空解碼字符串變量，開始新一輪解碼。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='';%解碼完成后，撥號(hào)變量清空，方便下一次撥號(hào)。%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);%利用聲卡播放撥號(hào)音set(gcf,'CurrentAxes',handles.axes1);NSignal=length(Signal);t=1/8000:1/8000:NSignal/8000;plot(t,Signal);grid;%畫信號(hào)的時(shí)域波形xlabel('單位：〔s〕');Spectrum=fft(Signal);Spectrum=fftshift(Spectrum);%計(jì)算信號(hào)的頻譜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;%畫信號(hào)的頻譜圖axis([-2000,2000,0,200]);xlabel('單位：〔Hz〕');functionx=dtmf(key);fs=8000;N=0.1*fs;%信號(hào)時(shí)間為100ms,N=Tpmin*Fs；Tpmin根據(jù)頻率分辨率得到，DTMF信號(hào)的最小頻率間隔為73HZ,故至少需要110點(diǎn)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;