Let h(n) be a real filter with non zero linear or nonlinear phase response. Show that the following operations are equivalent to filtering the signal x(n) with a zero-phase filter
(a) g(n) = h(n) * x(n)
f(n) = h(n) * g(–n)
y(n) = f(–n)
(b) g(n) = h(n) * x (n)
f(n) = h(n) * x(–n)
y(n) = g (n) + f (–n)