Noise reduction system
US4953217A · kind A · utility
48Cited by
5References
21Claims
0Family size
Assignee
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Key dates
| Filing date | Apr 7, 1989 |
| Grant date | Aug 28, 1990 |
| Priority date | — |
| Expiry date | Apr 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K2210/3045
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
In order to overcome problems in an active noise reduction system of sound buffets at low frequency and signal enhancement caused by imperfect transfer functions of a noise cancelling sound generator and a microphone, one or more high pass filters for reducing low frequency signals are provided in a feedback loop between the sound generator and microphone. A low pass filter is provided for extending the bandwidth of the system but which does not introduce unduly large phase shifts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.