A finite-duration [[discrete-time signal]] is a sequence of numbers that is zero-valued outside a limited range of time instants. For example, the discrete-time signal $x(n)$ is a finite-duration signal if it verifies the condition: $x(n) = 0, n<N_1 \wedge n > N_2$ where $n, N_1, N_2 \in \mathbb{Z}$