Noise reduction circuit for telephones
US6798881B2 · kind B2 · utility
15Cited by
14References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1999 |
| Grant date | Sep 28, 2004 |
| Priority date | — |
| Expiry date | Jun 7, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/087
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A system for processing audio signals in two channels, wherein each channel includes a plurality of band pass filters for dividing the signal in each channel into a plurality of bands and a plurality of variable gain amplifiers coupled one each to a band pass filter. Control logic coupled to the variable gain amplifiers prevents the signals in adjacent bands within a channel from being attenuated simultaneously. The control logic attenuates the signals in one channel in accordance with the signal in the corresponding bands in the other channel. In some circumstances, the signal in the band in the one channel is attenuated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.