| 摘要 |
PROBLEM TO BE SOLVED: To provide an outdoor public address device in which broadcasting is executed to regional residents on a real time basis and which is strong against fading. SOLUTION: The electric field strength of radio waves is detected by receiving the radio waves transmitted from a master station, and at the same time, the radio waves are demodulated as signals, and control signals to show its own state requested by control signals from the master terminal are transmitted in an emergency transmitting/receiving part 21. Transmission/reception of radio signals between nearby outdoor public address devices, in which a complementary group is set beforehand, is executed in a complementation transmitting/receiving part 22. The request from the master terminal is judged by decoding the signals demodulated at the emergency transmitting/receiving part 21 and the complementation transmitting/receiving part 22, the control signals to show its own state are prepared and they are transmitted from the emergency transmitting/receiving part 21, and broadcasting signals from the master station are transmitted with the other outdoor public address device, in which its own station and the complementary group are set, in the order from larger electric field strength to the other via the complementation transmitting/receiving part 22 in a main control part 23. A public address part 24 makes public address of the demodulated voice signals by the control of the main control part 23. COPYRIGHT: (C)2004,JPO |
