Safety noise protection equipment - has radiated signal outside hearing range converted to audible inside equipment

摘要

The safety noise protection equipment allows acoustic communication between those working in very noisy surroundings, without harm to their hearing. An emitter radiates a signal outside the range of hearing, and this generates in ear protection equipment an audible frequency. This signal conversion is independent of the protection provided by the equipment. The latter can be arranged to provide even and maximum protection over the whole audible range, while the radiated signal can be ultrasonic.