| 摘要 |
PURPOSE:To separate an optical signal generating section and optical signal receiving section from an information signal inserting section to prevent the influence of electromagnetic induction, by sending periodical optical pulse signals transmitted from the optical signal generating section to the optical signal receiving section after information signals are inserted into the optical pulse signals by means of a prescribed means. CONSTITUTION:An optical signal generating section 1 is composed of a signal generator 2 and electrooptic converter 3 and generates periodical optical pulse signals A'. The signals A' are inputted in the optical branching device 6 of an information signal inserting section 5 through an optical fiber transmission line 4 and branched into branched outputs B and C. The output C is directly inputted in a photocoupler 9. The other output B is inputted in the photocoupler 9 after it is delayed by an optical pulse width or more by an optical delaying line 7 and its level is changed by means of an external information input F at an optical variable attenuator 8. A signal E obtained by coupling the two outputs B and C at the photocoupler 9 is inputted in an optical signal receiving section 11 through an optical fiber transmission line 10. The receiving section 11 is composed of a photoelectric converter 12 and information demodulator 13 and separates and demodulates the external information F. |
