Active silencer
US4805733A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 7, 1987 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Jul 7, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K2210/3044
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
An active silencer provided in a pipe which has one end reaching the noise source and the other end open, the active silencer being provided with a sound generating means which is provided at the sidewall of the pipe facing inside the pipe, a sound collecting means which is provided outside the pipe close to the other end and which detects noise dissipated from the pipe opening, a phase leading means which outputs a lead phase output signal which is advanced from the phase of an output signal of the sound collecting means by a phase corresponding to a predetermined time determined by the distance between the sound generating means and the sound collecting means; and a drive means which outputs a signal constituting the lead phase output signla inverted in phase as a drive signal for the sound generating means, the predetermined time .tau. being set so that .tau.=L/C, wherein the distance between the sound generating means and the sound collecting means is L and the speed of sound is C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.