27.

(Cyclical Redundancy Check CRC) . CRC-16 CRC-32, 16 32 . CRC , . . . , (m, m + 16)- CRC-16 (m, m + 32)-

CRC-32.

CRC , (-), (-). CRC, . CRC-16 - 16, CRC-32 32. - CRC-16/32 (CCITT). CRC-16, , - x16 + x12 + x5 + 1.

CRC-4 11010111, - x4 +x3 + x2 +1. x7 + x6 + x4 + x2 + x + 1, . . .

x7 + x6 + x4 + x2 + x + 1 x7 + x6 + x5 + x3

x4 + x3 + x2 + 1

x3 + x

x5 + x4 + x3 + x2 + x + 1 x5 + x4 + x3 + x

2 + 1

2 + 1 0101 -4 .

-, , .

- , , , . , . , - , , , .

: , , .

► 46

-4 10000000 101111001, - 4 + 1.