matlab 傅立叶识别字符,Matlab关于循环FFT(傅立叶分析)，取出幅值

global numG;

global zs;

typeval=get(hObject,'Value');

switch typeval

case 1

numG=4;

case 2

%  handles.starta=0;

numG=5;

case 3

numG=6;

%handles.starta=54

end

guidata(hObject,handles);

for k=1:numG

[filename,filepath]=uigetfile(...

{'*.txt;*.dat;*.mat','所有数据文件 (*.txt,*.dat,*.mat)';

'*.txt','TXT 文件   (*.txt)';...

'*.dat','DATA 文件  (*.dat)';...

'*.mat','MAT 文件   (*.mat)';...

'*.*','所有 文件   (*.*)'});

str=[filepath filename];

set(handles.path,'string',str);

fid=fopen(filename,'rb');

[data,count]=fscanf(fid,'%e',inf);

fclose(fid);

a(k)=data(2161);

j=1;

for i=2:3:2159;

Ydata(j,1)=data(i);

j=j+1;

end;

suju(:,k)=Ydata;

axes(handles.jwyi);cla(gca)

plot(1:720,suju(:,k));%角位移曲线

xlabel('角度');

ylabel('角位移');

yk=fft(suju(:,k));%进行fft变换

magk=abs(yk)*2/length(yk);%求幅值

f=(0:length(yk)-1);%*fs/length(y);%进行对应的频率转换

%        n=f*60/zs;%谐次

set(handles.xieci,'string',3);

handles.magk=magk;

axes(handles.flye);

h=stem(f,magk);%傅立叶曲线

set(handles.fuzhi1,'string',max(magk));

xlabel('谐次');

ylabel('幅值');

xlim([0 20]);

title('傅立叶谐次图');

end

handles.a=a;

set(handles.gl1,'string',handles.a(1));

set(handles.gl2,'string',handles.a(2));

set(handles.gl3,'string',handles.a(3));

set(handles.gl4,'string',handles.a(4));

handles.suju=suju;

handles.n=n;

handles.m=m;

guidata(hObject,handles);