| 摘要 |
PROBLEM TO BE SOLVED: To obtain a drive-through system capable of preventing speech diffusion to a circumference by forming a sound field only within a specified range to prevent noise. SOLUTION: A parametric speaker 3 converts an ultrasonic modulated signal into an audible sound and directionally radiating it, and a plane reflecting plate 4 is provided which reflects the directionally radiated sound 31 toward nearby the driver's seat of a vehicle 6 stopping at a stop position without changing the directivity of the radiation sound 31. COPYRIGHT: (C)2009,JPO&INPIT
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