DFT的定义 2丌 X(k)=∑ (k=0,1,2…N-1) r(ne n=0 2丌 jk (n=0,1,2…N-1) x(n 1 x(ke X(k) x(n X￥(k)=DFT[x(n) x(n)=DFTIX (K) x(n)= X(kWN k一 DFT的定义  − = − = 1 0 2 ( ) ( ) N n n N jk X k x n e  (k = 0,1, 2N −1)  − = = 1 0 2 ( ) 1 ( ) N k n N jk X k e N x n  (n = 0,1, 2N −1)  − = = 1 0 ( ) ( ) N n nk n WN X k x  − = − = 1 0 ( ) 1 ( ) N k nk WN X k N x n X(k) = DFT[x(n)] x(n) = IDFT[X(k)]