科学家认为，公共广播系统、扩音器、自动门等利用超声波控制的设备日益增多，可能会导致“超声病”的流行。

Scientists say that a boom in public announcement systems, loudspeakers and automatic doors may be spawning an epidemic of ultrasonic sickness.

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公共广播系统是专为公共场所提供背景音乐、广播及消防报警的专业设备。

The public broadcast system specially provides the background music for the public place, it is also the specialized equipment which broadcast the fire alarm to the public.

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