| 摘要 |
PURPOSE:To obtain an optical transmission system whose picture quality is not deteriorated even if a normal photocoupler is used while using one optical fiber by transmitting a control signal during a synchronizing signal detection period for a video signal. CONSTITUTION:The video signal obtained by an ITV camera comes to an optical receiver 6 through an optical transmitter 5, a photocoupler 9A, an optical fiber 10 and a photocoupler 9B. A synchronizing signal detection circuit 12 makes the output signal B of the video signal A at a level H during the period of the horizontal synchronizing signal included in the video signal A, and passes a control signal C coming from a terminal 3 through an AND gate 19. A control signal D comes in the optical receiver 8 through the optical fiber 10 from the optical transmitter 7. A triggerable multivibrator 18 reproduces the control signal C, which is transmitted to the ITC camera from an output terminal 4. The output of the optical transmitter 7 leaks to the optical receiver 6 through the photocoupler 9B. However, during said period only the horizontal synchronizing signal is transmitted, which never affects picture quality. |
