# Where does convolution fit in DFT?

I am trying to understand where does the convolution fit in Discrete Fourier Transform. I know that convolution is producing a third signal from two other signals. I also know that DFT transforms one signal from time to frequency domain.

So, what is the relationship between the two (if any)?

• In Fourier space convolution is a simple multiplication, so to make convolution of two signals with equal length you should make their FFT, multiply them, make inverse FFT of product. Absolutely correlated signals will give you a large peak in zero shift value of convolution. – Eddy_Em Apr 3 '13 at 7:28