DFT ( Discrete Fourier Transform )
Definition DFT $ X(k) = \sum^N-1_n=0{x(n)*exp(-j2pikn/N) dn } k = 0, 1, 2, ..., N-1 $
Inverse DFT (IDFT) $ x[n] = (1/N)\sum^N-1_k=0{X(k)*exp(j2pikn/N) dk } n = 0, 1, 2, ..., N-1 $
Definition DFT $ X(k) = \sum^N-1_n=0{x(n)*exp(-j2pikn/N) dn } k = 0, 1, 2, ..., N-1 $
Inverse DFT (IDFT) $ x[n] = (1/N)\sum^N-1_k=0{X(k)*exp(j2pikn/N) dk } n = 0, 1, 2, ..., N-1 $