FFT of Signal doesn´t work well

Hi,

I would like to have a FFT of a constant signal with two Dirac jumps.

My signal is correct, but my FFT shows nothing. May somebody could help me?

It´s the following code:

t = [1:361] ; % in Grad, Gesamtumdrehung sind 360°

f(t(1):t(end)) = 0; % f = Signal

% Magnets

N = 23; % Amount of magnets

n = 2; % selected magnets

a = 360/n ; % distance between magnets

% Signal 1 = Dirac

tsprung = 20;

tsprung2 = tsprung + a;

f(tsprung)= 1;

f(tsprung2)= f(tsprung);

subplot(211);

plot (t,f);

xft = fft(f);

xabs = abs(xft);

subplot(212);

plot (xabs);

set(gca, 'XTick',[0:20:360])

set(gca, 'YTick',[0:0.1:1])

xlabel ('Position der Magneten in Grad');

ylabel ('Stoß');

legend ('Signal');

THANKS A LOT !

Answer 1

[KALYAN ACHARJYA]

xabs(2nd Plot) is the absolute of fft ??

[Cedric Burkhart]

Yes it should show the absolut numbers of the fft, but if it works without the abs then it will be good as well.

I just wanna see how the frequency-spectrum is before and after the dirac jump.