Ex. 1 determine the des of a impulse train Consider the periodic impulse train 1, n=rN, r is any integer SIn-rN 0. otherwise N points xn -N-N+1 -2-10 2∴……N-1NN+1N+2 Solution =∑如=W 014 Ex. 8.1 determine the DFS of a impulse train ◆Consider the periodic impulse train        = =  − =  =− otherwise n rN r is any integer x n n rN r 0, 1, , ~  n 0 1 -N -N+1…… -2 -1 2 …… N-1 N N+1 N+2 …… N points xn ~     1 ~ 0 1 0 =  = = − = N N n kn X k  n WN W Solution: