Question

The impulse response of a discrete-time LTI system is
h(n) = δ(n) + 2δ(n − 1) + δ(n − 2).
Sketch the output of this system when the input is
............∞
x(n) =∑δ(n − 4 k).
...........k=0

Answer 1

$δ(n) \times δ(n − 1) = δ(n − 2)$