Finite-Dimensional LTi Discrete-Time Systems a more convenient form of the z-domain representation of the difference equation is given ∑ k ()=∑Pk=6X(=) k=0 k=0 Copyright C 2001, S K MitraCopyright © 2001, S. K. Mitra 6 Finite-Dimensional LTI Discrete-Time Systems • A more convenient form of the z-domain representation of the difference equation is given by d z Y(z) p z X(z) M k k k N k k k         =           = − = − 0 0