| 摘要 |
<p>PURPOSE:To prevent useless consumption of power when there is no signal, to receive a valid signal without any lack of a part, and to prevent an erroneous action caused by beams other than a light signal beam by providing a circuit to turn on a power supply and a circuit to turn off the power supply to a second transmitter-receiver. CONSTITUTION:To the second transmitter-receiver 102 that receives a radio signal transmitted from a second transmitter-receiver 101, the power supply turning-in circuit 107 and the power supply turning-off circuit 108 are provided. In order to start the transmitter-receiver 101 to transmit a radio signal from the transmitter-receiver 102, an operator manipulates the manual input part 110 of the latter to turn on the power supply by the power supply turning-in circuit 107. Accordingly, the transmitter-receiver 102 can be ready well in time for the starting transmission in the transmitter-receiver 101, and can receive radio signals accurately from the beginning. If the part 110 is not manipulated, the power supply is not turned on, hence an erroneous action can be prevented. In case the part 110 or the transmission of radio signals from the transmitter-receiver 101 stops, since the additional information of a radio signal is no longer detected, the power supply turning/off circuit 108 cuts off power supply, and the useless power consumption when the signal is absent can be prevented.</p> |
