DFT question. can someone assist?

[scdoro]

Hi all,

Can anyone help me comment on the below code and explain how the function works.I am not sure how this function works and why is there a mid value in the calculation?

Thanks a lot!

regards

 

[vadkudr]

The main string is
H=fftshift(fft(x,n));

it calculates Fourier transform of length 'n'.

All other strings above calculate only respective frequency points from -pi to pi.

What namely for you is not clear?