| 摘要 |
<p>PURPOSE:To perform the prescribed protecting operation only for the minimum necessary train-board radio stations by specifying a control signal transmitted from a base radio station around a train at an accident time by the received control signal in the maximum input base radio station of a transmitted signal from the train in accident. CONSTITUTION:When an accident occurs in a train with radio station 10, a transmission signal 16 of carrier F1+ modulation wave f2 is transmitted from the train station. When base stations 2-4 in the service area of the station 10 receive it, they first compare and switch the SN with each other, thereby selecting the optimum receiving base station 3. When the station 3 transmits the protection instruction signal 14 of carrier F2+modulation wave f1+modulation wave f2, and it simultaneously controls the adjacent base stations 2, 4 to transmit signal capable of being received only by the train-board radio stations 7-9. Accordingly, the stations 2, 4 respectively transmit protection instruction signals 13, 15 of F2+f2, F2+f1. Thus, the stations 7, 8 detect the modulation wave f1 in the signals 14, 15, thereby performing the prescribed protecting operation. The station 9 detects the modulation wave f2 of the signal 13, thereby performing the prescribed protecting operation.</p> |
