Communications Blockset    
BCH Decoder

Decode a BCH code to recover binary vector data

Library

Block sublibrary of Channel Coding

Description

The BCH Decoder block recovers a binary message vector from a binary BCH codeword vector. For proper decoding, the first two parameter values in this block should match the parameters in the corresponding BCH Encoder block.

The input is the binary codeword vector and the first output is the corresponding binary message vector. If the BCH code has message length K and codeword length N, then the input has length N and the first output has length K. If the input is frame-based, then it must be a column vector.

The number N must have the form 2M-1, where M is an integer greater than or equal to 3. For a given codeword length N, only specific message lengths K are valid for a BCH code. To see which values of K are valid, use the bchpoly function in the Communications Toolbox. No known analytic formula describes the relationship among the codeword length, message length, and error-correction capability.

The second output is the number of errors detected during decoding of the codeword. A negative integer indicates that the block detected more errors than it could correct using the coding scheme.

The sample times of all input and output signals are equal.

The Error-correction capability T parameter either:

The block runs faster in the first case above. You can use the bchpoly function in the Communications Toolbox to calculate the error-correction capability.

Dialog Box

Codeword length N
The codeword length, which is also the vector length of the first input.
Message length K
The message length, which is also the vector length of the first output.
Error-correction capability T
Either the error-correction capability of the code, or zero. A zero forces the block to calculate the error-control capability when initializing.

Pair Block

BCH Encoder

See Also

bchpoly (Communications Toolbox)


  Baseband PLL BCH Encoder