Impulse Response
Define the impulse response h: Integers → Reals by
∀ n ∈ Integers,
h(n) = d, if n = 0
h(n) = cT An -1 b , if n > 0
Then the output can be written,
y(n) = cT An s0 + ∑ (m = 0 to n) h(n- m) x(m)
Notice that if s0 = 0 and the input is the Kronecker delta function, or impulse:
x(m) = 1; if m = 0,
x(m) = 0; otherwise,
then ∀ n ∈ Integers,
y(n) = h(n).
So h is called the (zero state) impulse response of the system.