Noise reducing device
US5138664A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1990 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Mar 14, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K2210/3056
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
This invention is concerned with a device for reducing the external noise reaching the ear in extremely noisy places such as in the vehicle or construction sites. According to the present invention, the external noise in picked up by a microphone provided in the vicinity of an electro-acoustic transducer element, such as a headphone unit, provided in the vicinity of the wearer's ear, and the noise signal converted in this manner into electrical signals is produced as the acoustic signal by the electro-acoustic transducer element. The transfer characteristics and controlled in such a manner that the produced noise signal prove to be an acoustic signal which is of the same frequency spectrum and opposite in phase with respect to the external noise reaching the wearer's acoustic meatus from outside to reduce the external noise reaching the acoustic meatus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.