Method and apparatus for transition direction coding

TL;DR: In this paper, a method and apparatus for encoding data in the context of a digital system for communicating binary information, including code words, over a communications channel is presented, where a change in the bit pattern between a bit and a prior adjacent bit represents a transition having a direction.

Abstract: The present invention provides a method and apparatus for encoding data in the context of a digital system for communicating binary information, including code words, over a communications channel. The information communicated over the channel is synchronized by a system clock producing a plurality of system clock pulses having edges associated with the binary information, where a change in the bit pattern between a bit and a prior adjacent bit represents a transition having a direction. The present invention encodes data words of n-bits each into a plurality of code words of m-bits each by selecting from the set of m-bit binary numbers those binary numbers in which each bit either experiences a transition in the same direction as the system clock edge associated with that bit or experiences no transition from a prior adjacent bit to that bit. Each of the selected binary numbers is a code word. Each data word is preferably associated with a code word. Data words are preferably formed into a message, and each code word associated with each data word of the message is longitudinally serialized so that each code word is represented by a serial bit pattern. The associated code words of the message are then transmitted in parallel with each other in a plurality of groups or "stacks".