When trying to configure the block parameters for the Viterbi Decoder,a problem can occur. In particular,an error can be seen when trying to change the constraint length and convolutional codes. The error is as follows:
"Viterbi Decoder 7.0 block: ERROR: Convolution 1 Code 0 width must be less then or equal to Constraint Length."
With the 12.x version of System Generator, if the Viterbi is in Standard Mode, the GUI does not allow you to change the convolutional codes on page 4 because these codes are not used in Standard Mode. However, the error still occurs if these codes are not changed. For 12.x a workaround is to change the Viterbi Decoder to Dual Decoder mode and then change the convolutional codes on page 4.
This problem is fixed in the 13.1 version of System Generator.