Augmented Parity Check Codes for Encoding of Asynchronous Sequential Machines

• Published in: IEEE transactions on computers Vol. C-22; no. 10; pp. 891 - 896
• Main Authors: Kashef, R.S., McGhee, R.B.
• Format: Journal Article
• Language: English
• Published: IEEE 01.10.1973
• Subjects: Asynchronous sequential machines; augmented parity check codes; general race-free codes; maximum distance partition
• ISSN: 0018-9340; 1557-9956
• DOI: 10.1109/T-C.1973.223614

Critical races can be avoided in the binary encoding of asynchronous sequential machines by making use of general codes employing-multistep changes in secondary variables to accomplish transitions between states. The shortest length code of this type presently available is Huffman's internmeshed row set code, which encodes race-free any 2 S O-row flow table with 2S o -1 bits. In this paper, a new class of codes called augmented parity check codes (APC codes) is introduced and proposed for race-free encoding. Some of the properties of these codes suggest that minimum codes may require only on the order of S o + log 2 S O bits.