%%%%Khod hambastegi va chegaliye teyfi
clc
clear
disp('babak mamaqani')
disp('Please Wait..........')
a=importdata('d:\gather.txt');%%%%%file path(man hameye record ha ro tu yek file gharar dadam ta rahat tar basham
a(:,1:2:19)=[];
a(isnan(a))=0;%%%%gharar dadane 0 jahate ham andaze kardane recordha
sigma=0;
sigma2=0;
for i=1:10;
    ap=a(:,i);
    %%%%mohasebeye zamane moasser
    for j=1:length(ap);
        sigma=ap(j,1)^2+sigma;
    end
    for k=1:length(ap);
        sigma2=ap(k,1)^2+sigma2;
        if sigma2/sigma<=0.05;
            first=k;
        elseif sigma2/sigma<=0.95;
            last=k;
        end
    end
    ap(1:first,:)=[];
    ap(last-first:length(ap))=[];
    %%%mohasebeye khod ham bastegi
    for d=1:length(ap);
    b(d,i)=ap(1,1)*ap(d,1);
end
end
t=0:0.005:42.81;%%%%zamane marbut be akharin shetabnegasht ba'd az tashih
f=b';
f=sum(f)/10;%%%%10=te'dade recordha
figure(1)
plot(t,f)%%%%rasme khod ham bastegi
hold on
plot(-t,f)
%%%%%chegaliye teyfi(tabdile fouriyeye khod ham bastegi)
dt=0.005;
m = length(f);                     
n = pow2(nextpow2(m));
y = fft(f,n);
AMP=abs(y(1:length(y)/2));
f=1/(2*dt)*linspace(0,1,length(AMP));
figure(2)
plot(f,AMP);