How can I compute fourier coefficient?

Hi I have a pulse and I want to compute the first 20 fourier coefficient of it. Would anyone help me to do this?

Answer 1

[Image Analyst]

f = fft(yourSignal);
f20 = f(1:20); % Extract first 20 coefficients.

[Ghazal Hnr]

oooo it has a code ?? thank you !!!