音頻頻譜分析儀設(shè)計與實現(xiàn)

1、實驗八音頻頻譜分析儀設(shè)計與實現(xiàn)一、實驗原理MATLAB是一個數(shù)據(jù)分析和處理功能十分強大的工程實用軟件，其數(shù)據(jù)采集工具箱為 實現(xiàn)數(shù)據(jù)的輸入和輸出提供了十分方便的函數(shù)和指令。本實驗基于聲卡與 MATLAB實現(xiàn)音頻信號頻譜分析儀。1、頻率(周期)檢測對周期信號來說，可以用時域波形分析來確定信號的周期，也就是計算相鄰兩個信號 波峰的時間差或過零點的時間差。采用過零點( ti)的時間差T (周期)。頻率即為f=1/T, 由于能夠求得多個T值，故采用他們的平均值作為周期的估計值。2、峰值檢測在一個周期內(nèi)，求出信號最大值ymax與最小值ymin的差得一半記為 A,同樣得到多個A值，但第一個A值對應(yīng)的ymax

2、和Ymin不是在一個周期內(nèi)搜索得到的，故以除第一個以外 的A值的平均作為幅值的估計值。3、相位檢測采用過零法，即通過判斷與同頻零相位信號過零點時刻，計算其時間差，然后換成相 應(yīng)的相位差。中=2冗(1-ti/T),同樣以中的平均值作為相位的估計值。4、數(shù)字信號統(tǒng)計量估計(1)峰值P的估計在樣本數(shù)據(jù)x中找出最大值與最小值，其差為雙峰值，雙峰值的一半即為峰值。(2)均值估計i r E(y)=y=N為樣本谷量。N(3)均方值估計21:2E(y r工廠(4)方差估計_ 1三“I(yE(y)25、頻譜分析原理時域分析只能反映信號的幅值隨時間的變化情況，除但頻率分量的簡單波形外，很難明確提示信號的頻率組成和

3、各頻率分量大小，而頻譜分析能很好的解決此問題。(1) DFT 與 FFT對于給定的日域信號 y,可以通過Fourier變換得到頻域信息 Y。Y可按下式計算耨-1N-1r(/)=8。*/的 +*儂。w 00式中，N為樣本容量，A t = 1/Fs為采樣間隔。采樣信號的頻譜是一個連續(xù)的頻譜，不可能計算出所有的點的值，故采用離散Fourier變換(DFT),即理-1了我的=鄧如皿所演=0,12， Q式中，Af =Fs/N。但上式的計算效率很低，因為有大量的指數(shù)(等價于三角函數(shù))運算，故實際中多采用快速 Fourier變換(FFT)。其原理即是將重復(fù)的三角函數(shù)算計的中間結(jié)果保存起來，以減少重復(fù)三角函數(shù)

4、計算帶來的時間浪費。由于三角函數(shù)計算的重復(fù)量相當大，故FFT能極大地提高運算效率。(2)頻率、周期的估計對于Y(kAf),如果當kAf = f時，Y(kAf)取最大值，則f為頻率的估計值，由于采樣間隔的誤差，f也存在誤差，其誤差最大為Af/ 2。周期T=1/fo從原理上可以看出，如果在標準信號中混有噪聲，用上述方法仍能夠精確地估計出原標 準信號的頻率和周期。(3)頻譜圖為了直觀地表示信號的頻率特性，工程上常常將 Fourier變換的結(jié)果用圖形的方式表示,即頻譜圖。以頻率f為橫坐標, 以頻率f為橫坐標, 以頻率f為橫坐標, 以頻率f為橫坐標,|Y(f)|為縱坐標，可以得到幅值譜； arg Y(f

5、)為縱坐標，可以得到相位譜; Re Y為縱坐標，可以得到實頻譜; Im Y(f)為縱坐標，可以得到虛頻譜。根據(jù)采樣定理，只有頻率不超過Fs/2的信號才能被正確采集，即 Fourier變換的結(jié)果中頻率大于Fs/2的部分是不正確的部分，故不在頻譜圖中顯示。即橫坐標 f 0, Fs/2 6、模塊劃分模塊化就是把程序劃分成獨立命名且可獨立訪問的模塊，每個模塊完成一個子功能，把這些模塊集成起來構(gòu)成一個整體，可以完成制定的功能，滿足用戶需求。二、實驗內(nèi)容設(shè)計一個音頻頻譜分析儀，功能包括：(1)音頻信號輸入，從聲卡輸入、從 WAV文件輸入、從標準信號發(fā)生器輸入；(2)信號波形分析，包括幅值、頻率、周期、相位

6、的估計，以及統(tǒng)計量峰值、均值。均方值和方差的計算。(3)信號頻譜分析，頻率、周期的估計，圖形顯示幅值譜、相位譜、時頻譜、虛頻譜和功率譜的曲線。三.實驗結(jié)果1.聲卡輸入(1)正弦波聲音信號頻譜分析儀下者l里文帕2tHitI白山了-為折時復(fù)M第1 .克利留1024匹口分析所營口時續(xù)分行幅垣3節(jié)間及打所的用川竄m豹血峰值加與9的揖軍5 口 M密均0.04的1能Ufl99 965B的萬杭4M7.36相悅a 5方建S0O2.212樊續(xù)也寸析的用口中口 01的圜期軍皿皿他*A.-* q a ii sanipEialt! 5120總掙點瞪產(chǎn)卡 開雎錄音 InwetoifliMa10245如工件鐵嶷正缶宣任弋

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10、azciECWM成件送鬃閂埠產(chǎn)9 1SSISX3打開文件.W3-,聲a 7期里 晤H 相相ie gj| oSS生成渡彩卜*林楸1福斯相捏 UtMiHi 制 2H MH tHMKiffld程序function varargout = fanwenhan(varargin)gui_Singleton = 1; TOC o 1-5 h z gui_State = struct(gui_Name , mfilename,.gui_Singleton , gui_Singleton,.gui_OpeningFcn , fanwenhan_OpeningFcn,.gui_OutputFcn , fanwe

11、nhan_OutputFcn,.gui_LayoutFcn , 口，.gui_Callback ,);if nargin & ischar(varargin1)gui_State.gui_Callback = str2func(varargin1); endif nargoutvarargout1:nargout = gui_mainfcn(gui_State, varargin:); elsegui_mainfcn(gui_State, varargin:);endfunction fanwenhan_OpeningFcn(hObject, eventdata, handles, varar

12、gin) handles.inputtype=0; TOC o 1-5 h z xlabel(handles.plot1,freqency(Hz);xlabel(handles.plot2,freqency(Hz);xlabel(handles.plot3,freqency(Hz);xlabel(handles.plot4,freqency(Hz);xlabel(handles.plot5,freqency(Hz);ylabel(handles.plot1,amplitude );ylabel(handles.plot2,phase(rad) );ylabel(handles.plot3,re

13、al );ylabel(handles.plot4,Imaginary);ylabel(handles.plot5,power );handles.output = hObject;functionvarargout = fanwenhan_OutputFcn(hObject, eventdata, handles)varargout1 = handles.output;functionfigure1_CreateFcn(hObject, eventdata, handles)function timeanalyse_Callback(hObject, eventdata, handles)F

14、s=str2double(get(findobj(Tag , samplerate ), String );N=str2double(get(findobj(Tag , samplenum ), String );if handles.inputtype=0msgbox( No wave exist! Please choose a input type!);return ; end n=1;ymax=max(handles.y(1) handles.y(2);ymin=min(handles.y(1) handles.y(2);from=str2double(get(handles.poin

15、tfrom,String );to=str2double(get(handles.pointto,String );if from1 | to-from5; msgbox( Error range! ); return ; end for i=from+2:to-1;if handles.y(i-1)0 & handles.y(i-2)=0 & handles.y(i+1)0if handles.y(i)=0 ti(n)=i;elseti(n)=i-handles.y(i)/(handles.y(i)-handles.y(i-1); end amp(n)=(ymax-ymin)/2;ymax=

16、0;ymin=0;n=n+1; elseif ymaxhandles.y(i) ymin=handles.y(i);endend end n=n-1;for i=1:n-1T(i)=ti(i+1)-ti(i);endfreq=Fs/mean(T); set(handles.outt, set(handles.outfreq,StringString,1/freq);,num2str(freq);set(handles.outamp,String,num2str(mean(amp(2:n-1);phase=2*pi*(1-(ti(1:n-1)-1)./T+f100r(ti(1:n-1)-1)./

17、T);set(handles.outphase,Stringset(handles.outpeak,Stringrom:to)/2); set(handles.outmean,Stringset(handles.outmeansquare, set(handles.outs, String,num2str(mean(phase);,(max(handles.y(from:to)-min(handles.y(f,mean(handles.y(from:to);String,mean(handles.y(from:to).A2);,std(handles.y(from:to)A2);functio

18、n WAVfile_Callback(hObject, eventdata, handles) h=findobj( Tag , filename );set(h, enable , on); TOC o 1-5 h z h=findobj( Tag , freq ); set(h,enable,off);h=findobj(Tag, amp);set(h,enable,off);h=findobj(Tag, phase);set(h,enable,off);set(findobj(Tag,recordtime),enable , offset(handles.channel,enable,o

19、n);set(handles.fileopen,enable,on);set(handles.gensig,enable ,off);set(handles.wavetype,enable,off);set(handles.add,enable , off);set(handles.startrecord,enable , off );functionsoundcard_Callback(hObject, eventdata, handles)set(findobj(Tag,recordtime),enable , onh=findobj(Tagfilename);set(h, enable

20、,off);h=findobj(Tagfreq );set(h, enable ,off);h=findobj(Tagamp);set(h, enable ,off);h=findobj(Tagphase );set(h, enable ,off);set(handles.channel,enable,off);set(handles.fileopen,enable,off);set(handles.gensig,enable ,off);set(handles.wavetype,enable,off); TOC o 1-5 h z set(handles.add, enable , off

21、);set(handles.startrecord,enable , on);function generator_Callback(hObject, eventdata, handles) h=findobj(Tag,filename);set(h,enable,off);h=findobj( Tag , freq ); set(h,enable,on);h=findobj(Tag,amp);set(h,enable,on);h=findobj(Tag,phase);set(h,enable,on);set(findobj( Tag , recordtime ), enable , off

22、); set(handles.channel,enable , off );set(handles.fileopen,enable, off );set(handles.gensig,enable , on);set(handles.wavetype,enable, on);set(handles.add, enable , on);set(handles.startrecord,enable,off);functionfilename_Callback(hObject, eventdata, handles)functionfilename_CreateFcn(hObject, eventd

23、ata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionfreq_Callback(hObject, eventdata, handles)functionfreq_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObje

24、ct, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionamp_Callback(hObject, eventdata, handles)functionamp_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white );elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor);endfunctionphas

25、e_Callback(hObject, eventdata, handles)functionphase_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white );elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor)；endfunctionsamplerate_Callback(hObject, eventdata, handles)functionsamplerate_CreateFcn(h

26、Object, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionsamplenum_Callback(hObject, eventdata, handles)functionsamplenum_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor

27、, white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionampfreq_CreateFcn(hObject, eventdata, handles)functionrecordtime_Callback(hObject, eventdata, handles)functionrecordtime_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white

28、 ); elsefunctionset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endstartrecord_Callback(hObject, eventdata, handles)Fs=str2double(get(findobj(Tag , samplerate ), String );),Strinhandles.y=wavrecord(str2double(get(findobj(Tag , recordtimeg )*Fs, Fs, int16);handles.inputtype=1;

29、 guidata(hObject,handles); plot(handles.time,handles.y); title( WAVE); ysize=size(handles.y) set(handles.samplenum,String ,num2str(ysize(1);function fileopen_Callback(hObject, eventdata, handles) temp = wavread(get(findobj(Tag , filename ), String );channel=str2double(get(handles.channel,String );ha

30、ndles.y=temp(:,channel); handles.inputtype=2; guidata(hObject,handles); plot(handles.time,handles.y); title( WAVE); ysize=size(handles.y) set(handles.samplenum,String ,num2str(ysize(1);function gensig_Callback(hObject, eventdata, handles) Fs=str2double(get(findobj(Tag , samplerate ), String );N=str2

31、double(get(findobj(Tag , samplenum ), String );x=linspace(0,N/Fs,N); soundtype=get(handles.wavetype,Value);frequency=str2double(get(handles.freq,String );amp=str2double(get(handles.amp,String );phase=str2double(get(handles.phase,String );switch soundtype case 1 y=amp*sin(2*pi*x*frequency+phase); cas

32、e 2 y=amp*sign(sin(2*pi*x*frequency+phase); case 3 y=amp*sawtooth(2*pi*x*frequency+phase,0.5); case 4 y=amp*sawtooth(2*pi*x*frequency+phase); case 5 y=amp*(2*rand(size(x)-1); otherwise errordlg(Illegal wave type, Choose errer );end if get(handles.add, Value 尸=0.0 handles.y=y;elsehandles.y=handles.y+

33、y;endhandles.inputtype=3;guidata(hObject,handles);plot(handles.time,handles.y);title( WAVE);axis(0 N -str2double(get(handles.amp,String )str2double(get(handles.amp,String );functionoutfreq_Callback(hObject, eventdata, handles)functionoutfreq_CreateFcn(hObject, eventdata, handles)if ispcset(hObject,

34、BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionoutamp_Callback(hObject, eventdata, handles)functionoutamp_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, d

35、efaultUicontrolBackgroundColor ); endfunctionoutphase_Callback(hObject, eventdata, handles)functionoutphase_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, );BackgroundColor,get(0, defaultUicontrolBackgroundColorendfunctionoutpeak_Callback(hObjec

36、t, eventdata, handles)functionoutpeak_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionoutmean_Callback(hObject, eventdata, handles)functionoutmean_CreateFcn(hObject, eventdata,

37、 handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionoutmeansquare_Callback(hObject, eventdata, handles)functionoutmeansquare_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white );

38、 elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionouts_Callback(hObject, eventdata, handles)functionouts_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white );else set(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor

39、)；endfunctionfoutfreq_Callback(hObject, eventdata, handles)functionfoutfreq_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionfoutamp_Callback(hObject, eventdata, handles)functio

40、nfoutamp_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionfoutphase_Callback(hObject, eventdata, handles)functionfoutphase_CreateFcn(hObject, eventdata, handles)if ispcset(hObje

41、ct, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunction function if ispcedit18_Callback(hObject, eventdata, handles)edit18_CreateFcn(hObject, eventdata, handles)set(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,ge

42、t(0, defaultUicontrolBackgroundColor ); endfunctionedit19_Callback(hObject, eventdata, handles)functionedit19_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionedit20_Callback(hO

43、bject, eventdata, handles)functionedit20_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionedit21_Callback(hObject, eventdata, handles)functionedit21_CreateFcn(hObject, eventdata

44、, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, );BackgroundColor,get(0, defaultUicontrolBackgroundColorendfunction freqanalyse_Callback(hObject, eventdata, handles) Fs=str2double(get(findobj(Tag , samplerate ), String );N=str2double(get(findobj(Tag , samplenum ), String );

45、if handles.inputtype=0msgbox( No wave exist! Please choose a input type!);return ; end from=str2double(get(handles.pointfrom,String );to=str2double(get(handles.pointto,String );sample=handles.y(from:to); f=linspace(0,Fs/2,(to-from+1)/2); Y=fft(sample,to-from+1); C,I=max(abs(Y); set(handles.foutt,Str

46、ing ,1/f(I);set(handles.foutfreq,String ,f(I);Y=Y(1:(to-from+1)/2); plot(handles.plot1,f,2*sqrt(Y.*conj(Y); plot(handles.plot2,f,angle(Y); plot(handles.plot3,f,real(Y); plot(handles.plot4,f,imag(Y); plot(handles.plot5,f,abs(Y).A2); xlabel(handles.plot1,freqency(Hz); TOC o 1-5 h z xlabel(handles.plot

47、2,freqency(Hz);xlabel(handles.plot3,freqency(Hz);xlabel(handles.plot4,freqency(Hz);xlabel(handles.plot5,freqency(Hz);ylabel(handles.plot1,amplitude );ylabel(handles.plot2,phase(rad) );ylabel(handles.plot3,real );ylabel(handles.plot4,Imaginary);ylabel(handles.plot5,power );functionpointfrom_Callback(

48、hObject, eventdata, handles)functionpointfrom_CreateFcn(hObject, eventdata, handles)if ispc set(hObject, BackgroundColor , white ); else set(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor )； endfunctionfunctionpointto_Callback(hObject, eventdata, handles)pointto_CreateFcn(hObject,

49、eventdata, handles) if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); end function play_Callback(hObject, eventdata, handles)Fs=str2double(get(findobj(Tag , samplerate ), String );wavplay(handles.y,Fs);function scale_Callback(h

50、Object, eventdata, handles)val=get(hObject, value );val=10A(val*5+1);x=get(handles.xmove, Value )*str2double(get(handles.samplenum,String)；axis(handles.time,x val+x min(handles.y) max(handles.y);function scale_CreateFcn(hObject, eventdata, handles) usewhitebg = 1; if usewhitebgset(hObject, Backgroun

51、dColor ,.9 .9 .9); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor )； end function scale2_Callback(hObject, eventdata, handles) val=get(hObject, value );val=10A(val*5+1);xlim(handles.plot1,0 val);xlim(handles.plot2,0 val);xlim(handles.plot3,0 val);xlim(handles.plot4,0 val);f

52、unction scale2_CreateFcn(hObject, eventdata, handles) usewhitebg = 1;if usewhitebgset(hObject, BackgroundColor ,.9 .9 .9); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionchannel_Callback(hObject, eventdata, handles)functionchannel_CreateFcn(hObject, eventdata, handles)if ispcset(hObject, BackgroundColor , white ); elseset(hObject, BackgroundColor ,get(0, defaultUicontrolBackgroundColor ); endfunctionwavetype_Callback(hObject, eventdata, handles)functionwavetyp