Accession Number : ADA307480
Title : Development of An Earplug Equipped with Active Noise Reduction (Ontwikkeling van een Oordrp met Active Geluidreductie).
Descriptive Note : Final rept.,
Corporate Author : HUMAN FACTORS RESEARCH INST TNO SOESTERBERG (NETHERLANDS)
Personal Author(s) : Steeneken, H. J. ; Verhave, J. A. ; Goverts, S. T.
PDF Url : ADA307480
Report Date : 18 DEC 1995
Pagination or Media Count : 32
Abstract : In cooperation with Philips Asset and Groeneveld Etcea an earplug was developed equipped with an active noise reduction system. The goat, to achieve a extra active attenuation of 20 dB, is almost reached. An attenuation of 18 dB was obtained for frequencies below 500 Hz. Reduction of the loop-gain results in an extension of the frequency range with a tower attenuation. The system uses a specific telephone with an improved frequency response with respect to the standard walkman telephones. The casts of both telephone types are equivalent. The special designed telephone, however, has a low impedance which requires a complex adaptation to the electronic control unit. The use of a personal moulded earplug as connection between the ear canal and the electra acoustic part of the system gives some leakage. Application of a standard earplug gives better results and is general applicable, however, the fixation with the ear canal is not as robust as with a personal moulded plug.
Descriptors : *NOISE REDUCTION, *TELEPHONE SYSTEMS, *FREQUENCY RESPONSE, FREQUENCY, CONTROL SYSTEMS, FOREIGN TECHNOLOGY, NETHERLANDS, ELECTRONIC EQUIPMENT, TOWERS, ATTENUATION, ADAPTATION, IMPEDANCE, DUTCH LANGUAGE, HEARING, EAR, CANALS, EAR PROTECTORS, FOREIGN LANGUAGES, DEAFNESS.
Subject Categories : Radiofrequency Wave Propagation
Distribution Statement : APPROVED FOR PUBLIC RELEASE