Companding noise reduction system with simultaneous encode and decode
US6556685B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1998 |
| Grant date | Apr 29, 2003 |
| Priority date | — |
| Expiry date | Nov 6, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G7/004
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A system and method for reducing noise in an audio signal. The system includes an encoder, a decoder and a single feedforward sidechain for generating a control signal that is used as input to a variable gain element in the encoder and in the decoder. The system is substantially audibly transparent, minimizes audible noise modulation, minimizes dynamic distortion of low frequency signals due to a level detector tracking these waveforms, minimizes distortion of signals due to phase shift in a transmission channel, minimizes distortion of fast, high-level transients due to the attack time of the level detector, and has virtually no effect on the audio signal if the level of the signal stays within a reasonable range around the nominal signal level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.