音频频谱分析仪设计与实现

1、实验八音频频谱分析仪设计与实现一、实验原理MATLAB是一个数据分析和处理功能十分强大的工程实用软件，其数据采集工具箱为 实现数据的输入和输出提供了十分方便的函数和指令。本实验基于声卡与 MATLAB实现音频信号频谱分析仪。1、频率(周期)检测对周期信号来说，可以用时域波形分析来确定信号的周期，也就是计算相邻两个信号 波峰的时间差或过零点的时间差。采用过零点( ti)的时间差T (周期)。频率即为f=1/T, 由于能够求得多个T值，故采用他们的平均值作为周期的估计值。2、峰值检测在一个周期内，求出信号最大值ymax与最小值ymin的差得一半记为 A,同样得到多个A值，但第一个A值对应的ymax

2、和Ymin不是在一个周期内搜索得到的，故以除第一个以外 的A值的平均作为幅值的估计值。3、相位检测采用过零法，即通过判断与同频零相位信号过零点时刻，计算其时间差，然后换成相 应的相位差。中=2冗(1-ti/T),同样以中的平均值作为相位的估计值。4、数字信号统计量估计(1)峰值P的估计在样本数据x中找出最大值与最小值，其差为双峰值，双峰值的一半即为峰值。(2)均值估计i r E(y)=y=N为样本谷量。N(3)均方值估计21:2E(y r工厂(4)方差估计_ 1三“I(yE(y)25、频谱分析原理时域分析只能反映信号的幅值随时间的变化情况，除但频率分量的简单波形外，很难明确提示信号的频率组成和

3、各频率分量大小，而频谱分析能很好的解决此问题。(1) DFT 与 FFT对于给定的日域信号 y,可以通过Fourier变换得到频域信息 Y。Y可按下式计算耨-1N-1r(/)=8。*/的 +*侬。w 00式中，N为样本容量，A t = 1/Fs为采样间隔。采样信号的频谱是一个连续的频谱，不可能计算出所有的点的值，故采用离散Fourier变换(DFT),即理-1了我的=邓如皿所演=0,12， Q式中，Af =Fs/N。但上式的计算效率很低，因为有大量的指数(等价于三角函数)运算，故实际中多采用快速 Fourier变换(FFT)。其原理即是将重复的三角函数算计的中间结果保存起来，以减少重复三角函数

4、计算带来的时间浪费。由于三角函数计算的重复量相当大，故FFT能极大地提高运算效率。(2)频率、周期的估计对于Y(kAf),如果当kAf = f时，Y(kAf)取最大值，则f为频率的估计值，由于采样间隔的误差，f也存在误差，其误差最大为Af/ 2。周期T=1/fo从原理上可以看出，如果在标准信号中混有噪声，用上述方法仍能够精确地估计出原标 准信号的频率和周期。(3)频谱图为了直观地表示信号的频率特性，工程上常常将 Fourier变换的结果用图形的方式表示,即频谱图。以频率f为横坐标, 以频率f为横坐标, 以频率f为横坐标, 以频率f为横坐标,|Y(f)|为纵坐标，可以得到幅值谱； arg Y(f

5、)为纵坐标，可以得到相位谱; Re Y为纵坐标，可以得到实频谱; Im Y(f)为纵坐标，可以得到虚频谱。根据采样定理，只有频率不超过Fs/2的信号才能被正确采集，即 Fourier变换的结果中频率大于Fs/2的部分是不正确的部分，故不在频谱图中显示。即横坐标 f 0, Fs/2 6、模块划分模块化就是把程序划分成独立命名且可独立访问的模块，每个模块完成一个子功能，把这些模块集成起来构成一个整体，可以完成制定的功能，满足用户需求。二、实验内容设计一个音频频谱分析仪，功能包括：(1)音频信号输入，从声卡输入、从 WAV文件输入、从标准信号发生器输入；(2)信号波形分析，包括幅值、频率、周期、相位

6、的估计，以及统计量峰值、均值。均方值和方差的计算。(3)信号频谱分析，频率、周期的估计，图形显示幅值谱、相位谱、时频谱、虚频谱和功率谱的曲线。三.实验结果1.声卡输入(1)正弦波声音信号频谱分析仪下者l里文帕2tHitI白山了-为折时复M第1 .克利留1024匹口分析所营口时续分行幅垣3节间及打所的用川窜m豹血峰值加与9的揖军5 口 M密均0.04的1能Ufl99 965B的万杭4M7.36相悦a 5方建S0O2.212樊续也寸析的用口中口 01的圜期军皿皿他*A.-* q a ii sanipEialt! 5120总挣点瞪产卡 开雎录音 InwetoifliMa10245如工件铁嶷正缶宣任弋

7、茂生嘉5a四方。 Ffll*和依1000.5打开文件生立波黑-1，立麟杆位电M特性eie irm 1Q(2)方波声音信号频谱分析仪存香，气文HMU11002201廿甘疔以第1京到案1024 口分折断前萧w R- K- JU 1UBI MO J1U时用力状朝燧舟折用第0 口 1的占的峰值100W54?师均立0.15315Ufl100由力值1QODO相检Qgg方强10009.7Unwenh力时摒守析的申场出*三折的果 因卬UBI的蒯 朝军WHH 口samptetenla51 的一采样点质1。24尸卡开始录昔住号养生曷1KImwrc川MM M 北 HK % 海 1ttj IHd m J Bffl H

8、 i卜 LEM生成波强由文件餐引耳塞打开文件D4Y1 m L4W1 HEC(3)三角波声音信号频谱分析仪场培耀粉精培思相m0 0199黑军5(1间西随雅0.019054fl9.22斯平50.0409均使-D.0&S5111幅M.0913埼方3334.62相推5,2124方建33&Whmenh甘hfc坤析弟Ji相抵照性M鞋三由苻信号澳生井打开文件力所计置 M1* H作者，痴D11函如?案科电规f、-J- -Uwrpitrtfi， 5120卡 开始录音 nnwrecwd lit他朝节-nrf*1英茹特性HI 1Ei KW 却X!(4)锯齿波声音信号频谱分析仪怕立 范文同加11%必7分时时票4第1吉

9、到第10M萩口分析所书点甘窿普培旦用西0.019&605Q9.9O2250.040S均值).100131幅,M.0225坤方悯33MlMi相也3.S41S方圣3纲也23学堤蹴8忻茎 罔期0019W3 项率$009窿iM盘性(5)白噪声声音信号频谱分析仪蚱者r范文tftRHIQfPKJT分析时就U第1点生僮1也4 JS 存析所有点时ti将麻匕-马雷 0323016峥值99.9543刿甲304部仍均-0 通 17637修区85.5165的方值3534.2B相粗26571方果3537.56IIM*l!l：rill眼埸分析培里颉喈域分析结累国1JUU(的&12Q-采祥点看W24口声卡 行蜡录音 Imr

10、azciECWM成件送鬃闩埠产9 1SSISX3打开文件.W3-,声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