| 摘要 |
PURPOSE:To obtain a stable receiving input from a low transmitting output by composing the outputs of plural radio transmitters and connecting the composed output to metallic pipes or metal embedded in plastic pipes on a baggage rack in each vehicle to use the metallic pipes or the like as an antenna. CONSTITUTION:The radio transmitters 81-83 are modulated by audible frequency from sound sources 71-73 of an acoustic service device 7, the outputs of the radio transmitters 81-83 are composed 80 and the composed output is distributed by a distributor 12a of a vehicle 11a. A part of the distributed outputs is received by the succeeding vehicle 11b through a coaxial cable 15a and the other is adjusted at a required level by a level adjuster 13a and then received by a receiver 6a through an antenna 14a. The metallic piles of the baggage rack or the like or an antenna embedded into the plastic pipes of the baggage rack are used as the antenna in the vehicle. Since the antenna is set up in a fixed range of the lengthwise direction of the vehicle, the distance between the antenna and the receiver can be reduced, so that the transmitting output can be dropped. Even if passengers move in the vehicle, stable reception can be attained because the interruption of radio waves may be prevented. |
