83.1 Discrete-Time Fourier Transform · The dTFtX(eio) of a sequence x叫lisa continuous function of o It is also a periodic function of a with a period 2T X(e (0o+2k -j(Oo+2 tk)n =∑ xinle yoon2mhn=∑xmle-10n=Y(eo§3.1 Discrete-Time Fourier Transform • The DTFT X(ej) of a sequence x[n] is a continuous function of  • It is also a periodic function of  with a period 2: =   =−  +  −  +  n j o k j o k n X e x n e ( 2 ) ( 2 ) ( ) [ ] j kn n j n x n e e o −   =− −  =  2 [ ] [ ] ( ) o o j n j n x n e X e   =− −  =  =