SYSTEM FOR TRANSMITTING OPTICAL BINARY DATA SIGNALS THROUGH AN OPTICAL FIBER WITH PILOT PULSES INSERTED BETWEEN TWO WIDE SPACED SUCCESSIONS OF DATA SIGNALS

摘要

ABSTRACT OF THE DISCLOSUREFor effective use of the optical energy and yet proper operation of anautomatic gain or threshold control circuit comprised by a receiver of an opti-cal data transmission system, a transmitter of the system produces an opticalbinary signal with at least one optical pilot pulse inserted between two se-quences of optical data pulses only when the two sequences are spaced widerfrom each other than a predetermined interval that would render the control cir-cuit no more operative and would thereby adversely affect correct reproductionof the data from an electrical binary signal derived from the received opticalbinary signal through the control circuit. By making the pilot pulses appearmore than a first prescribed duration after the last data pulse of the preced-ing sequence and a second prescribed duration before the first data pulse of thesucceeding sequence, electrical pilot pulse or pulses present in the electricalbinary signal are removed without deforming the reproduced data if each pre-scribed duration is longer than the pulse width of the electrical pilot pulseand furthermore a sum of the prescribed durations and the pulse width is notlonger than the predetermined interval. The removal is possible by providingthe electrical binary signal with successive delays decided in consideration ofthe prescribed durations and the pulse width and carrying out logic operation onthe electrical binary signal and the successively delayed signals if each opti-cal data pulse lasts longer than a sum of the delays.