function[f,sf]=T2F(t,st);
%This is a function ueing the FFT function to calculate a signal's Fourier
%Translation
%Input is the time and the signal vectors,the length of time must greater
%than 2
%Output is the frequency and the signal spectrum
dt=t(2)-t(1);
T=t(end);
df=1/T;
N=length(st);

f=-N/2*df:df:N/2*df-df;
sf=fft(st);
sf=T/N*fftshift(sf);