Abstract
The most common method to construct a t-error correct ing/all unidirectional error detecting (EC/AUED) code is to choose a t-error correcting (EC) code and then to append a tail in such a way that the new code can detect more than t errors when they are unidirectional. The tail is a function of the weight of the codeword. We present two new techniques for constructing t-EC/AUED codes. The first technique modifies the t-EC code in such a way that the weight distribution of the original code is reduced. So, a smaller tail is needed. Frequently, this technique gives less overall redundancy than the best available t-EC/AUED codes. The second technique improves the parameters of the tails with respect to previous results. © 1992 IEEE