二DTFT、DFS及DFT之间的关系 e Q=k X(e NC=N ∑ xn(n)e ∑x(n)e n=<N> nE<M X(k=X(e/ 饭3n=NC0,1,2…N-1) Ⅹ(k)是连续DTFT的等间隔采样二DTFT、DFS及DFT之间的关系 N k j k X e N c 2 ( ) 1 =  =   =  − =  − =  =         = = n N n N j k N n N n N j k k N N k j x n e x n e N X e Nc N    2 2 2 ( ) ( ) 1 ( ) ( ) ( ) ( 0,1, 2 1) = 2 = = − =  X k X e Nck k N N k j   X(k)是连续DTFT的等间隔采样