fftofsignal.m

调用.csv文件格式或者Excel格式文件实现Matlab数学算法：图像或图形的再现、时域和频域的信号分析和处理

%function spgram(SwaveFileNam,Winsiz,Winsiz,Shift,Base,Coltype);
clear;
[fname,pname]=uigetfile('*.csv','选择需要数据处理的文件');   %通过对话框读取数据文件
fp=fopen(strcat(pname,fname),'r');
Signl1=dlmread(strcat(pname,fname),',',1,0);
for t=1:10000
	Signlg(t)=Signl1(t,2);
end
for t=1:2
	Sample(t)=Signl1(t,1);
end
Signl=reshape(Signlg,10000,1);
% fclose(fp);
Fs=1/(Sample(2)-Sample(1))%采样率
Fs;


m=0;
for i=1:10000
    if Signl1(i,1)<0;
        m=m+1;
    else
        break;
    end
end
Lasttime=1000*Signl1(10000,1);

% 信号重现
figure
i=1:10000;
plot((i-m)*1e3/Fs,Signl);
% axis([-inf,inf,-0.20001,0.20001]);


% title('信号重现');
xlabel('时间t/ms','FontName','Times new Roman');
ylabel('幅度A/mV','FontName','Times new Roman');

figure
df=Fs/10000;
f=0:df:df*9999;
plot(f/1000000,abs(fft(Signl)));
axis([0,Fs/(2*1000000),-inf,inf]);
title('傅立叶变换');
xlabel('频率(MHz)');
ylabel('幅度');
figure