An Improvement on Constructions of t-EC/AUED Codes

A common method of constructing f-error correcting/all unidirectional error detecting (t-ECIAUED) codes is to choose a t E C code and then to append a tail such that the new code can detect all unidirectional errors. The tail is a function of the weight of the codeword. We present a technique to reduce the weight distribution of the CEC code so that the tail needed will be shorter in some cases. The weight distribution span of the code is reduced by eliminating the all-zero codeword and replacing it with a codeword of weight greater than 2 t + 1.