| 摘要 |
PROBLEM TO BE SOLVED: To provide a railroad vehicle public address system in which passengers can easily listen to the railroad vehicle guide broadcasting and even visually-handicapped persons and senior persons can determine the railroad vehicle without any mistake. SOLUTION: The public address system comprises a rolling stock condition acquisition unit 11 to acquire the rolling stock condition including at least one of the traveling speed, the traveling position and the door opening/closing condition of a rolling stock 20, a sound signal source 13 which maintains the sound guide data to be transmitted and generates the audible sound signal from the sound guide data, a sound start control unit 12 which selects the sound guide data corresponding to the condition of the rolling stock out of the sound guide data maintained by the sound signal source 13 and generates the sound signal source 13 according to the instruction of the sound start control unit 12, a directivity control unit 14 which controls the directivity by utilizing the carrier belonging to the ultrasonic range with respect to the audible sound signal generated by the sound signal source 13 according to the instruction of the sound start control unit 12, and a speaker 16 which radiates the audible sound by receiving the audible sound signal with the directivity thereof controlled by the directivity control unit 14. COPYRIGHT: (C)2005,JPO&NCIPI
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