A t-unidirectional error-detecting systematic code

A systematic code consists of codewords in which the check symbol is appended to the information symbol. Thus, data manipulation and encoding/decoding can be done in parallel. The Berger code is a well-known optimal systematic code for detecting all unidirectional errors. In VLSI circuits most of the errors are found to be unidirectional in nature. However, in many applications it may not be necessary to detect all unidirectional errors. Most faults, unless catastrophic in nature, do not cause errors in all the bits of the information and check symbol. Therefore, it may be enough to guarantee detection of every unidirectional error in t or fewer bits of the codeword, if t is reasonably large. In this paper we present such a t-unidirectional error-detecting code.