Dirac Delta functionδ[n]={1,n=00,n≠0=u[n]−u[n−1]\delta[n] = \begin{cases} 1, & n=0 \\ 0, & n \ne 0 \end{cases} = u[n] - u[n-1]δ[n]={1,0,n=0n=0=u[n]−u[n−1]