Active acoustic attenuation system for higher order mode non-uniform sound field in a duct
US4815139A · kind A · utility
68Cited by
6References
38Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1988 |
| Grant date | Mar 21, 1989 |
| Priority date | — |
| Expiry date | Mar 16, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K2210/3229
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A system is provided for increasing the frequency range of an active acoustic attenuation system in a duct without increasing cut-off frequency f.sub.c of the duct or otherwise splitting or partitioning the duct into separate ducts or chambers. The frequency range is increased above f.sub.c to include higher order modes. A plurality of cancelling model sets are provided. Each transverse portion of the acoustic pressure wave has its own set of an adaptive filter model, cancelling speaker, and error microphone. A single input microphone may service all sets.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.