实时音频信号采集和处理系统.m

音频处理Matlab程序

   'Parent'          , hFig,...
   'Style'           , 'pushbutton',...
   'Units'           , 'normalized',...
   'Position'        , [0.0150 0.0111 0.1 0.0556],...
   'Value'           , 1,...
   'String'          , '暂停',...
   'FontSize'        , 10,...
   'Callback'        , 'demoai_fft(''stop'', gcbf);');

hpop = uicontrol(...
   'Parent'          , hFig,...
   'Style'           , 'popupmenu',...
   'Units'           , 'normalized',...
   'Position'        , [0.35 0.007 0.1 0.0556],...
   'Value'           , 1,...
   'String'          , {'巴特沃斯滤波' '切比雪夫1型滤波'},...
   'FontSize'        , 10,...
   'Callback'        , '');

hmenu(1) = uimenu('Parent', hFig,...
   'Label', '文件');
hmenu(2) = uimenu(hmenu(1),...
   'Label', '关闭数据采集系统',...
   'Callback', 'demoai_fft(''close'',gcbf)');
hmenu(3) = uimenu('Parent', hFig,...
   'Label', '帮助');
% hmenu(4) = uimenu(hmenu(3),...
%    'Label', 'Data Acquisition Toolbox',...
%    'Callback', 'helpwin(''daq'')');
% hmenu(5) = uimenu(hmenu(3),...
%    'Label', 'demoai_fft',...
%    'Callback', 'helpwin(''demoai_fft'')'); %#ok<NASGU>

%%
% Store the handles in the data matrix.
data.handle.figure = hFig;%对句柄进行存储
data.handle.axes = hAxes;
data.handle.line = hLine;
data.handle.toggle = htoggle;
data.handle.hpop = hpop;
data.state = 0;

%%
% Set the axes handlevisibility to off.
set(hAxes, 'HandleVisibility', 'off');

%%
% Store the data matrix and display figure.
set(hFig,'Visible','on','UserData',data,'HandleVisibility', 'off');

%%
% Configure the callback to update the display.
set(data.ai, 'TimerFcn', @localfftShowData);

%% ***********************************************************************  
% 关闭数据采集系统。
function localClose(data)

%%
% Stop the device if it is running and delete the object.
if isvalid(data.ai)
   if isrunning(data.ai)
      stop(data.ai);
   end
   delete(data.ai);
end

%%
% Close the figure window.
delete(data.handle.figure);

%% ***********************************************************************  
% Stop or start the device.
function data = localStop(data)

%%
% Based on the state either stop or start.
if isrunning(data.ai)
   % Stop the device.
   stop(data.ai);
   set(data.handle.toggle, 'String', '开始');
   
   % Store the new state.
   data.state = 1;
else
   % Toggle the Start/Stop string.
   set(data.handle.toggle, 'String', '暂停');
   
   % Store the new state.
   data.state = 0;
   
   % Start the device.
   start(data.ai);
end

function [firstcross, lastcross] = localDaqCrossPt(data)
% Calculate the first & last crosspoints over the mean of the data.
% function returns 0 if no crosspoint is found.

firstcross = 0;
crossvalue = mean(data);
for i = 2:length(data)
    if(data(i-1) >= crossvalue && data(i) < crossvalue)
        firstcross = i;
        break;
    end
end

lastcross = 0;
for i = length(data):-1:2
    if(data(i-1) >= crossvalue && data(i) < crossvalue)
        lastcross = i;
        break;
    end
end

%% ***********************************************************************
% 对原始数据进行FFT运算、幅值运算、相位运算。
function [f, DAQfft,mag,phas] = localDaqfft(data,Fs,blockSize)

%%
% Calculate the fft of the data.
xFFT = fft(data,blockSize);
xfft = abs(xFFT);
DAQfft =xfft; %20*log10(xfft);
DAQfft = DAQfft(1:blockSize/2);

%%
% Avoid taking the log of 0.
index = find(xfft == 0);
xfft(index) = 1e-17; %#ok<FNDSB>
mag =20*log10(xfft);
mag = mag(1:blockSize/2);

phas =angle(xFFT);
phas = phas /3.1415926 * 180 ;
phas = phas(1:blockSize/2);

f = (0:length(DAQfft)-1)*Fs/blockSize; 
f = f(:);

%% ***********************************************************************
% 对原始数据先进行巴特沃斯滤波，然后进行FFT运算、幅值运算、相位运算。
function [d_filter,DAQfft_filter,mag_filter,phas_filter] = localDaqfft_filter1(d,Ft,blockSize)
Fp=800;        %通带截止频率
Fs=1200;        %阻带截止频率
Ap=1;           %通带纹波Ap=1
As=20;          %阻带纹波As=20
wp=2*pi*Fp/Ft;
ws=2*pi*Fs/Ft;
[n,wn]=buttord(wp,ws,Ap,As,'s');    %求低通滤波器的阶数和截止频率,n=8
[b,a]=butter(n,wn,'s');             %求S域的频率响应参数
[num,den]=bilinear(b,a,1);          %双线性变换实现S域到Z域的变换
d_filter=filter(num,den,d);      %对原始波形进行滤波

%%
% Calculate the fft of the data.
xFFT1 = fft(d_filter,blockSize);
xfft1 = abs(xFFT1);
DAQfft_filter =xfft1; %20*log10(xfft);
DAQfft_filter = DAQfft_filter(1:blockSize/2);

%%
% Avoid taking the log of 0.
index = find(xfft1 == 0);
xfft1(index) = 1e-17; %#ok<FNDSB>
mag_filter =20*log10(xfft1);%计算幅度谱
mag_filter = mag_filter(1:blockSize/2);

phas_filter =angle(xFFT1);%计算相位谱
phas_filter = phas_filter /3.1415926 * 180 ;%将弧度装换成角度
phas_filter = phas_filter(1:blockSize/2);

%% ***********************************************************************
% 对原始数据先进行切比雪夫1型滤波，然后进行FFT运算、幅值运算、相位运算。
function [d_filter,DAQfft_filter,mag_filter,phas_filter] = localDaqfft_filter2(d,Ft,blockSize)
Fp=1800;        %通带截止频率
Fs=2000;        %阻带截止频率
% Ft=8000;        %采集频率
Ap=1;           %通带纹波Ap=1
As=20;          %阻带纹波As=20
R=1;            %通带峰峰纹波R
wp=2*pi*Fp/Ft;
ws=2*pi*Fs/Ft;
[n,wp]=cheb1ord(wp,ws,Ap,As,'s');    %求低通滤波器的阶数和截止频率,n=8
[b,a]=cheby1(n,R,wp,'s');             %求S域的频率响应参数
[num,den]=bilinear(b,a,1);          %双线性变换实现S域到Z域的变换
d_filter=filter(num,den,d);      %对原始波形进行滤波

%%
% Calculate the fft of the data.
xFFT2 = fft(d_filter,blockSize);
xfft2 = abs(xFFT2);
DAQfft_filter =xfft2; %20*log10(xfft);
DAQfft_filter = DAQfft_filter(1:blockSize/2);

%%
% Avoid taking the log of 0.
index = find(xfft2 == 0);
xfft2(index) = 1e-17; %#ok<FNDSB>
mag_filter =20*log10(xfft2);%计算幅度谱
mag_filter = mag_filter(1:blockSize/2);

phas_filter =angle(xFFT2);%计算相位谱
phas_filter = phas_filter /3.1415926 * 180 ;%将弧度装换成角度
phas_filter = phas_filter(1:blockSize/2);

%% ***********************************************************************  
% 更新绘图。
function localfftShowData(obj,event)

%%
% 获取句柄。
data = obj.UserData;
hpop = data.handle.hpop;
hFig = data.handle.figure; %#ok<NASGU>
hAxes = data.handle.axes;
hLine = data.handle.line;

str = get(hpop, 'String');
val = get(hpop,'Value');
%%
% 提取最大值。
x = peekdata(obj, obj.SamplesPerTrigger);

%%
% FFT运算。
Fs = obj.SampleRate;
blockSize = obj.SamplesPerTrigger;
[firstcross, lastcross] = localDaqCrossPt(x);

if firstcross == 0 || firstcross == lastcross
    return;
end

fftx = x(firstcross:lastcross);
[f, DAQfft,mag,phas] = localDaqfft(fftx,Fs,blockSize);

switch str{val};
         case '巴特沃斯滤波' %使用巴特沃斯滤波
            [d_filter,DAQfft_filter,mag_filter,phas_filter] = localDaqfft_filter1(fftx,Fs,blockSize);%对输入信号先进行巴特沃斯滤波，然后进行FFT、幅值及相位运算
         case '切比雪夫1型滤波' % 使用切比雪夫1型滤波
            [d_filter,DAQfft_filter,mag_filter,phas_filter] = localDaqfft_filter2(fftx,Fs,blockSize);%对输入信号先进行切比雪夫1型滤波，然后进行FFT、幅值及相位运算
         end

%%
% 动态配置实时数据显示框的Y轴。
maxX=max(x);
minX=min(x);
yax1=get(hAxes(1),'YLim');
if minX<yax1(1),
   yax1(1)=minX;
end
if maxX>yax1(2),
   yax1(2)=maxX;
end
set(hAxes(1),'YLim',yax1)%设置hLine（1）句柄的属性，运用最大值法对Y轴进行控制
set(hAxes(5),'YLim',yax1)
%%
% 配置FFT子图的x轴和y轴。
set(hAxes(2),'XLim',[0 5000])
set(hAxes(2),'YLim',[0 50])
set(hAxes(6),'XLim',[0 5000])
set(hAxes(6),'YLim',[0 50])

%%
% 动态配置幅度子图的Y轴。
maxM=max(mag);
minM=min(mag);
yax2=get(hAxes(3),'YLim');
if minM<yax2(1),
   yax2(1)=minM;
end
if maxM>yax2(2),
   yax2(2)=maxM;
end
set(hAxes(3),'YLim',yax2)
set(hAxes(7),'YLim',yax2)
%%
% 动态配置相位子图的Y轴。
maxM=max(phas);
minM=min(phas);
yax2=get(hAxes(4),'YLim');
if minM<yax2(1),
   yax2(1)=minM;
end
if maxM>yax2(2),
   yax2(2)=maxM;
end
set(hAxes(4),'YLim',yax2)
set(hAxes(8),'YLim',yax2)
%%
% 更新显示。
set(hLine(1), 'YData', fftx(:,1));
set(hLine(2), 'XData', f(:,1), 'YData', DAQfft(:,1));%设置hLine(2)句柄的属性，X轴的数据与频率有关，Y轴的数据由快速傅里叶变换后获得
set(hLine(3), 'XData', f(:,1), 'YData', mag(:,1)); 
set(hLine(4), 'XData', f(:,1), 'YData', phas(:,1));
set(hLine(5), 'YData', d_filter(:,1));
set(hLine(6), 'XData', f(:,1), 'YData', DAQfft_filter(:,1));
set(hLine(7), 'XData', f(:,1), 'YData', mag_filter(:,1));
set(hLine(8), 'XData', f(:,1), 'YData', phas_filter(:,1));

str=get(data.handle.toggle, 'String');
if strcmp(str,'开始')
    set(data.handle.toggle, 'String', '暂停');
end

drawnow;