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Example: The linear block code with the following generator matrix is a [,,] Hadamard code: = ( ). Hadamard code is a special case of Reed–Muller code . If we take the first column (the all-zero column) out from G H a d {\displaystyle {\boldsymbol {G}}_{\mathrm {Had} }} , we get [ 7 , 3 , 4 ] 2 {\displaystyle [7,3,4]_{2}} simplex code , which ...
In coding theory, Hamming(7,4) is a linear error-correcting code that encodes four bits of data into seven bits by adding three parity bits. It is a member of a larger family of Hamming codes, but the term Hamming code often refers to this specific code that Richard W. Hamming introduced in 1950.
Formally, a parity check matrix H of a linear code C is a generator matrix of the dual code, C ⊥. This means that a codeword c is in C if and only if the matrix-vector product Hc ⊤ = 0 (some authors [1] would write this in an equivalent form, cH ⊤ = 0.) The rows of a parity check matrix are the coefficients of the parity check equations. [2]
Hence the rate of Hamming codes is R = k / n = 1 − r / (2 r − 1), which is the highest possible for codes with minimum distance of three (i.e., the minimal number of bit changes needed to go from any code word to any other code word is three) and block length 2 r − 1.
A generator matrix for a Reed–Muller code RM(r, m) of length N = 2 m can be constructed as follows. ... From this construction, RM(r,m) is a binary linear block ...
The block length of a block code is the number of symbols in a block. Hence, the elements c {\displaystyle c} of Σ n {\displaystyle \Sigma ^{n}} are strings of length n {\displaystyle n} and correspond to blocks that may be received by the receiver.
A generator matrix for a linear [,,]-code has format , where n is the length of a codeword, k is the number of information bits (the dimension of C as a vector subspace), d is the minimum distance of the code, and q is size of the finite field, that is, the number of symbols in the alphabet (thus, q = 2 indicates a binary code, etc.).
If C out and C in are linear block codes, then C out ∘C in is also a linear block code. This property can be easily shown based on the idea of defining a generator matrix for the concatenated code in terms of the generator matrices of C out and C in.