Separable codes for detecting unidirectional errors

Systematic and separable codes are widely used for error detection in VLSI circuits. Recently, systematic codes have been found for detecting t-unidirectional and burst unidirectional errors. In such codes, r checkbits are added to k information bits to form a codeword of length (k+r), and it is assumed that all 2^k possible information k-tuples are present. However, in many applications all 2^k possible k-tuples are not used. In such cases it is possible to obtain codes usually referred to as separable codes. The author presents separable codes which can detect t or all unidirectional errors