.
, ,
.
.
S0, S1, S2, S3 , + , S4, S5, S6, S7 - .
N=2
. | . | |||
X110 = X10 = X0 | ||||
X111 = X12 = X4 | ||||
X120 = X11= X2 | ||||
X121 = X13 =X6 | ||||
X210 = X20 = X1 | ||||
X211 = X22 = X5 | ||||
X220 = X21 = X3 | ||||
X221 = X23 =X7 |
, , .
, | |||
N / 2 | N / 2 | ||
2 (N / 4) = N / 2 | N / 4 | ||
4 (N / 8) = N / 2 | N / 8 | ||
. . . | . . . | . . . | . . . |
M -1 | N / 2 | 2 M -1 | N / 2 M -1 = 2 |
M | N / 2 | - | - |
N / 2 , M = log 2 N.
, (N / 2) log2 N N2 .
N.
2.4.
N - xn, N = 2M. . , - . x1m, - x2m.
xn x1m n = m, xn x2m - n = N/ 2 + m.