例N 4×2=8 2n,+ 0,1,2,3 0.1 k=4k,+k k,=0.1 kn=0,1,2,3 X1(kn)=∑x(n1,n形M=∑x(1,n0)W4 ni X1(,n0)=X1(ko,n0) nok (k2,n) X2(kk)=∑X(,n0)W=∑X1(0,n0 0=0 X(ki, ko)=X(k)1 2 例 N  rr  4 2  8 1 0 n  2n  n 1 0 0,1,2,3 0,1 n n      1 0 k  4k  k 1 0 0,1 0,1,2,3 k k            1 1 0 1 0 1 1 1 1 3 1 0 0 1 0 1 0 4 0 0 , , , r n k n k r n n X k n x n n W x n n W              0 0 0 0 ' 1 0 0 1 0 0 1 0 0 8 , , , n k n k X N k n  X k n W  X k n W       2 0 1 0 1 2 0 0 1 1 ' ' 2 0 1 1 0 0 1 0 0 2 0 0 , , , r n k n k r n n X k k X k n W X k n W            1 0  X k ,k  X k