| 摘要 |
PURPOSE:To obtain a picture of high-safety recording device by fixing the output of an information signal receiving means on a reception side at an expected level when a signal which indicates that a transmission-side power source is normal is not inputted to the reception side from an information signal transmission side. CONSTITUTION:A picture signal VD from the information signal transmission side is sent to terminals 1 and 2 of a connector CN2 through a balanced transmission line and inputted to a differential receiver 3 in a picture recording device which uses a laser. Further, a power-ready signal PR indicating that the transmission- side power source is normal is sent to a terminal 14. The signal PR is passed through the CR filter consisting of a resistance 17 and a capacitor 18 to remove its noise and inputted to the strobe terminal ST of the receiver 3 through a Schmitt circuit 19 and an inverter 20. When the signal PR is present, a terminal ST is at a level H and the output of the receiver 3 drives the laser 6 through a laser driving circuit 4. When the signal PR is ceased, the terminal ST is held at a level L and the output of the receiver 3 is still held at the level L, preventing a runaway of the laser device. |
