Helmet Integrated Communication System with Optically Driven Earplug

"A helmet based crew communication system is designed incorporating an opticallydriven earplug as well as active noise reduction signal processing at the crewstation. The optically driven earplug is added to the helmet communication systemto both increase the passive noise rejection through use of an earplug as well aswell as to improve intelligibility through use of an active earplug speaker. Theearplug is optically driven through free space to eliminate the wire connection ofconventional active earplugs to ease helmet don and doff limitations.The earplug small size and freedom from helmet connections also allows the helmet tocontinue to have conventional ear cup speakers for redundancy and use in active noisecancellation. Sensing microphones of either a conventional or fiber optic type arealso included for use with digital signal processing using compact low powerDSP chips. Active earplugs for improved communication in noisy environmentsincluding industrial, medical and law enforcement environments."