I have gone through the poly2trellis common. with this command I am able to construct the non systematic code but I wanted to construct the systematic code where there are 3 input line and four output line. In my problem 3 input line is directly connected to the output line and fourth output is determined from the 2 input combination using register and exOR(convolution coder). now can we construct this type ma code using the build in function available in Matlab. Hope get the response