按照上述思路继续对A(k)和B(k)作奇偶序列分解 令r=2,r=2+1,|=0,1,…N4-1,则有: A(k)=∑x(41)W4+∑x(41+2m241 =0 ∑x(4)W+W∑x(41+2)w =0 令 C()=∑x(4)W k=0.1..N (4212) % D(k)=∑x(4C+2) k=0.1.… 4.213) A(k=c(k)+wk dth )k=01,…M (4214) N Alk =C(k)-Wk∠D(k)k=0,1 1(4215)按照上述思路继续对A(k)和B(k)作奇偶序列分解。 令r=2l,r=2l+1,l=0,1, …,N/4-1,则有: 令 则 ( ) ( ) ( ) ( ) ( ) ( ) − = − = − = + − = = + + = + + 1 4 0 2 4 1 2 0 4 1 4 0 2 1 2 1 4 0 2 2 4 4 2 4 4 2 N l l k N k N N l l k N N l l k N N l l k N x l W W x l W A k x l W x l W ( ) ( ) 1 4 4 0,1, , 4 1 4 = = − − = C k x W k k N N N o (4.212) ( ) ( ) 1 4 4 2 0,1, , 4 1 4 = + = − − = D k x W k k N N N o (4.213) ( ) ( ) ( ) 1 4 0,1, 2 A k = C k +W D h k = N − k N (4.214) ( ) ( ) 1 4 0,1, 4 2 = − = − + C k W D k k N N A k k N (4.215)