| 摘要 |
PURPOSE:To prevent signals from being interrupted in the middle of transmission by transmitting optical signals while switching the power according to a control signal level concerning this signal transmitter and the receiver even when an obstacle to interrupt the optical signal exists on a space. CONSTITUTION:The signal transmitter detects the optical level of a control signal C transmitted from the reception side. When the detected level is higher than a prescribed level (in the state of no obstacle existent on the space), a 1/N pulse signal (power save signal) detecting the rise and fall of a prescribed digital signal is transmitted. When the detected level is lower than the prescribed level (in the state of having the obstacle on the state), an inputted digital signal A is outputted as it is. At the receiver, a discrimination circuit 6 discriminates this outputted signal and when it is the 1/N pulse signal, the signal can be converted to the original digital signal. Thus, the signals can be prevented from being interrupted, and power can be saved. |
