离散周期序列的傅立叶级数DFS的正逆运算对 Xn(k)=∑ x(n)e n=0.1.2..N-1 xn(n)= ∑X,()k=02.N-1 N k=0 X(k)和x(m)取主值周期,得离散傅立叶变换 (DFT)的正逆运算对 X(k)=∑ JAn nk (ne ∑x(m x(n)=∑X(kk3n1X(kmW k=0 N k=0( ) 0,1,2... 1 1 ( ) ( ) ( ) 0,1,2... 1 2 2 1 0 1 0 = = − = = −   − = − = − X k e k N N x n X k x n e n N j kn N k p p N n j kn p p N N   离散周期序列的傅立叶级数(DFS)的正逆运算对 和 取主值周期，得离散傅立叶变换 (DFT)的正逆运算对 X (k) x(n) n k N k j n k N k N n n k N n j kn X k W N X k e N x n X k x n e x n W N N − − = − − = − = − = −     = = = = 1 0 1 0 1 0 1 0 ( ) 1 ( ) 1 ( ) ( ) ( ) ( ) 2 2  