Causality Condition of a Discrete-Time LTI System If the lti system is also causal, then O Asx[n]=x2[m]forn≤mo ∑k]x1[n0-k]=∑kx2[n- k=0 k=0 This implies ∑1{m-]=∑hk]x2{m-k 〓一00 k Copyright C 2001, S K MitraCopyright © 2001, S. K. Mitra 8 Causality Condition of a Discrete-Time LTI System • If the LTI system is also causal, then • As • This implies x [n] x [n] 1 = 2 n  no for [ ] [ ] o no y n y 1 = 2    =  = − = − 0 2 0 1 k o k o h[k]x [n k] h[k]x [n k]   − =− − =− − = − 1 2 1 1 k o k o h[k]x [n k] h[k]x [n k]