Definition
DFT $ X(k) = \sum{x(n)exp(-j2pikn/N) dn }^N-1_n=0 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 $
