Communications Blockset

Convolutional Encoding

The Convolutional Encoder, in the Convolutional sublibrary of the Channel Coding library, encodes the data from the Bernoulli Random Binary Generator. The example uses the industry standard rate 1/2 convolutional code, with constraint length 7, defined by the encoder diagram below.

Convolutional Encoder Schematic Block Diagram

You can describe the encoder structure by a pair of binary numbers (having the same length as the code's constraint length) that specify the connections from the delay cells to the modulo-2 addition nodes. In this case, the first ouput corresponds to the binary number 1111001, where each 1 indicates the position of a delay cells whose bit goes to the upper addition node. The second output corresponds to 1011011. Converting these two binary numbers to octal produces the octal pair [171 133], which you can enter into the Code generator field in the mask for the Convolutional Encoder block.

See Encoding Using a Convolutional Code for details.

Random Source Generation

Puncturing