Coding device, pulse regenerating device, and communications system

Abstract

It is an object of the present invention to provide coding techniques which allow for higher efficiency and easier synchronization with coded data. In order to attain the object, a coding device according to the present invention converts 2-bit informational data into 4-bit coded data according to a predetermined coding rule. According to the coding rule employed in the coding device, one of four possible kinds of bit strings of informational data is converted into alternately a bit string of four bits in which each of values of two successive bits is “1” and a bit string of four bits in which each of values of all bits is “0”. Then, the other kinds of bit strings are converted into bit strings of four bits which differ from one another, in each of which a value of only one bit is “1”.

1 . A pulse regenerating device for regenerating a first pulse signal which is generated at a transmitting end of a communications system, said pulse regenerating device being provided at a receiving end of said communications system, wherein
 said first pulse signal is converted into a plurality of second pulse signals having a predetermined period at said transmitting end and said second pulse signals are input to said pulse regenerating device through a transmission line, and   said pulse regenerating device comprises:   a serial-parallel converter which detects input of a given second pulse signal, and outputs in parallel said second pulse signals including said given second pulse signal which are serially input for a predetermined time period from the time of detecting input of said given second pulse signal;   a regeneration determiner for determining whether or not said first pulse signal is regenerated based on the number of said second pulse signals which are output in parallel from said serial-parallel converter; and   a regenerated pulse supplier for generating a third pulse signal as a regenerated signal of said first pulse signal when said regeneration determiner determines that said first pulse signal is regenerated.   
   
   
       2 . The pulse regenerating device according to  claim 1 , wherein
 said serial-parallel converter outputs in parallel said second pulse signals after shaping said second pulse signals.   
   
   
       3 . The pulse regenerating device according to  claim 1 , wherein
 each of said second pulse signals is an optical signal,   said pulse regenerating device further comprises a photoelectrical converter for converting said second pulse signals into electrical signals, and said electrical signals into which said second pulse signals are converted are input to said serial-parallel converter.   
   
   
       4 . A communications system comprising:
 a transmitting device for generating a first pulse signal, converting said first pulse signal into a plurality of second pulse signals having a predetermined period, and outputting said second pulse signals; and   a receiving device for regenerating said first pulse signal from said second pulse signals which are input from said transmitting device through a transmission line, wherein   said receiving device includes:   a serial-parallel converter which detects input of a given second pulse signal and outputs in parallel said second pulse signals including said given second pulse signal which are serially input for a predetermined time period from the time of detecting input of said given second pulse signal;   a regeneration determiner for determining whether or not said first pulse signal is regenerated based on the number of said second pulse signals which are output in parallel from said serial-parallel converter; and   a regenerated pulse supplier for generating a third pulse signal as a regenerated signal of said first pulse signal when said regeneration determiner determines that said first pulse signal is regenerated.