# Labview inverse Fourier transform: Why can't I visualize Gibb's effect (or ringing)?

I am studying electrical engineering and have an assignment which I have been working on for couple weeks, but can't solve.

I have a discontinuous function as shown below and applied a FFT on it, which can be seen on the right.

On the bottom right corner is the inverse FFT plot in order to visualize the Gibb's effect, but I am not able to see it.

Why isn't the Gibb's effect showing up in this case?

• The FFT/IFFT, for the same number of points, is supposed to perfectly reconstruct the signal. If you want the Gibbs phenomenon, use a greater number of points (which will give you the leakage), or plot the sum of odd harmonics generating a square wave, as seen in the Wikipedia page. Also, what you have there is quite the tapered signal, which means that there is a triangle involved, which, in turn, means the harmonics will be more attenuated than the ones of a square wave. Commented Jan 4, 2021 at 9:54
• Thanks concerned citizen. So by using a greater number of points you mean more points in calculating the FFT and therefore less points for the IFFT? Commented Jan 4, 2021 at 10:11