1 % A script for display the process of Fourier Transform of FID 2 % FID stands for Free Induction Decay,which is a signal over time domain.We 3 % can get the signal over frequency through fourier transform.And FID is 4 % one of the most important signal form 5 %function s=s(t,M,T,w) 6 %s=M*exp(-t/T).*cos(w*t); 7 %M=10; 8 %T=1; 9 %w=200*pi;10 T=1;11 N=128;12 t=linspace(0,T,N);13 %s=s(t,M,T,w);14 s=10*exp(-t).*cos(200*pi*t);15 subplot(2,1,1);16 plot(t,s);17 xlabel(‘t‘);18 ylabel(‘signal intensity‘);19 title(‘FID signal in time domain‘);20 dt=t(2)-t(1);21 f=1/dt;22 f=f*(0:N-1)/N;23 S=fft(s);24 subplot(2,1,2);25 plot(f,abs(S));26 xlabel(‘Frequency‘);27 ylabel(‘Amplitude |S(k)|‘)28 title(‘FID over frequency domain through Fourier Transform‘);