| 摘要 |
<p>PURPOSE:To find out a delimiter position of an n-bit cyclic code or abbreviated cyclic code with a simple circuit by dividing a consecutive bit stream with a generation polynomial and reducing a residue of a generating polynomical before 2nd division to detect the n-bit cyclic code or abbreviated cyclic code included in the bit stream based on the result of the 1st division. CONSTITUTION:An exclusive OR circuit 12 is inserted between 1st and 2nd stages, between 5th and 6th stages and between 6th and 7th stages of a divider 1. An output at a final stage of a 40-bit shift register 10 is inputted to the exclusive OR circuit 12 and a decoder 11 is provided, which detects it that bits in each register of the divider 1 are all zero or have a specific bit pattern. The divider 1 divides 40-bit data sequence by a generation polynomial G(X)=(X<8>+X<2>+X+1) and the residue (X<6>+X<2>+X) of X<40>/G(X) is subtracted from the quotient, so that (X<6>+X<2>+X) is subtracted in advance from the divider 1 to exclude the effect of X<40>.</p> |
