Error-limiting coding using information-lossless sequential machines

An information4ossless sequential machine is essentially a machine whose input sequence may be recovered from knowledge of its output sequence. A situation is considered in which such a machine is used as the encoder for a communication system. With a noiseless channel, the information losslessness enables the input to the encoder to be recovered by a decoder which is the inverse (possibly delayed) of the encoder. This paper investigates the effects of transient errors in such a system and shows that there are encoders for which the decoder is incorrect only temporarily following arbitrary errors anywhere in the system. Each such encoder has input sequences which resynchronize the encoder following errors, as well as output sequences which resynchronize the decoder.