DFT · Cyclic boundary conditions

Re{exp(i2πkn/M)} = cos(2πkn/M)

g̃[n] = (1/M) ∑_k=0^M−1 X[k] exp(i2πkn/M) ⇒ g̃[n+M] = g̃[n]

c = IDFT₂{DFT₂(g_pad) · DFT₂(h₀)} · M = 16 + 2p

r = (K−1)/2 · p ≥ r ⇒ M = 16 + 2p ≥ 16 + K−1