Circuit for encoding an asynchronous binary signal into a synchronous coded signal

摘要

Successive intervals of an asynchronous binary signal are examined for the occurrence of transitions and each transition is encoded into a 2-bit binary code word. The occurrence of two transitions within a predetermined interval of time indicates that the asynchronous signal is distorted. A first code word is generated in response to the first transition to indicate to remote decoding apparatus the occurrence of the first transition within the interval of actual ocurrence. A second code word is generated in response to the second transition to indicate to the remote decoding apparatus the occurrence of the second transition in an interval immediately subsequent to the interval in which the second transition actually occurred. Polarity information is periodically transmitted to the decoding apparatus to ensure that the polarity of the asynchronous signal reproduced by the decoding apparatus is the same as the polarity of the original asynchronous signal.