This is what I have done so far(adsbygoogle = window.adsbygoogle || []).push({});

Here is the the formula for the Fourier transform. I expect to get a sinc function, which I am but it doesn't match it by scale.Code (Text):

t = -5:.01:4.99; // this give us our rect function from -.5 to .5

x = abs(t) <= .5;

subplot(2,1,1) // creates a subplot for the rect function

plot(t,x)

axis([-2 2 -1 2]) // sets the axis

T_s = .001; // The calculation of the discrete Fourier Transform

F_s = 1./T_s;

N = 1000;

n = -N/2.:1.:(N/2.)-1;

f = -F_s/2.:1.:(F_s/2.)-1;

X_f = T_s*x*exp(-1i*2*pi*f'*n*T_s);

z = fft(X_f);

subplot(2,1,2)

plot(abs(X_f))

[PLAIN]http://img580.imageshack.us/img580/1699/fourier.jpg [Broken]

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Discrete Fourier Transforms without using FFT function

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**