| 摘要 |
PROBLEM TO BE SOLVED: To allow a pedestrian to hear a sound for permitting passage clearly and prevent the sound for permitting passage from being treated as noise in the surroundings when it is silent at night effectively. SOLUTION: This acoustic device for pedestrian signal is provided with a generation circuit for outputting a signal for permitting passage, an amplifier for amplifying the signal for permitting passage outputted from the generation circuit, a speaker for outputting the signal for permitting passage outputted from the amplifier as the sound for permitting passage, and a sound pressure control circuit connected with an input side of the amplifier and detecting noise level of a crosswalk to control output of the speaker. The sound pressure control circuit is provided with a pattern analysis circuit for analyzing a change pattern of noise level to change output of the speaker by the change pattern of noise level detected by the pattern analysis circuit. In a state of a low noise pattern in which a generation rate of noise peak is small as compared with a high noise pattern having high generation rate of noise peak at which noise level increases up to a peak value, output of the speaker for noise level is controlled to a small value. COPYRIGHT: (C)2006,JPO&NCIPI
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