Method of actively controlling noise, and apparatus thereof
US5689572A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1994 |
| Grant date | Nov 18, 1997 |
| Priority date | — |
| Expiry date | Dec 8, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K2210/3039
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
In an active noise-reduction controlling apparatus, there are provided a reference sensor for outputting a reference signal corresponding to information about a noise source, a noise-reduction error sensor for detecting a noise-reduction condition, an adding acoustic wave source controlled to produce an acoustic wave having the same amplitude as that of an acoustic wave received at the noise-reduction error sensor and having a phase opposite to that of the acoustic wave received as the noise-reduction error sensor; a first adaptive digital filter for processing the reference signal to output a control signal of the adding acoustic wave source, a second adaptive digital filter for setting a predicted value of a transfer function between an input signal of the adding acoustic wave source and an output signal of said noise-reduction error sensor, a filter coefficient controlling unit for optimizing a coefficient of the first adaptive digital filter with employment of the predicted value of the transfer function and the output of the noise-reduction error sensor, and a control unit for correcting the predicted value of the transfer function in accordance with an environmental change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.