EMERGENCY BROADCASTING SYSTEM WITHIN A CLOSED SPACE AND A METHOD THEREOF, SPECIALLY RELATED TO MONITORING A RECEIVED STATE OF A BROADCASTING SIGNAL TO SERVICE AN EMERGENCY BROADCASTING PROGRAM WITH AM/FM RADIO BROADCAST FREQUENCIES

摘要

PURPOSE: An emergency broadcasting system within a closed space and a method thereof are provided to prevent various RFs from being combined through the same leakage cable, and to operate an emergency broadcasting output device in an emergency only, thereby removing interference of radio signals and preventing signal loss by monitoring a received state of a radio broadcasting signal. CONSTITUTION: A main controller(200) comprises as follows. An FM transmission device(202) wirelessly delivers a signal of a microphone(201). An emergency broadcasting button(203) is used for interface control. A microcomputer(204) transmits a control command to the FM transmission device(202). A master wireless data modem(205) operates a signal command in an emergency. The second and third RF switches(207,208) switch an emergency broadcasting transmission line. An emergency broadcasting transmission antenna(C-100) outputs an emergency broadcasting signal. A wireless data modem antenna(A-300) is wirelessly connected to a master modem antenna(A-200). Plural wireless data modem antennas(A-301¯A-30(n)) are wirelessly connected to both ends of plural wireless speakers(300-30(n)).