Automatic gain selector for a noise suppression system
US4630305A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 1985 |
| Grant date | Dec 16, 1986 |
| Priority date | — |
| Expiry date | Jul 1, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2225/43
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An automatic gain selector is disclosed for use with a noise suppression system which performs speech quality enhancement upon a noisy speech signal available at the input to generate a noise-suppressed speech signal at the output by spectral gain modification. The channel gain controller (240) of the present invention produces a modification signal (245), comprised of individual channel gain values, for application to a channel gain modifier (250). A particular gain table set is automatically selected from one of a plurality of gain tables (450) by a selector switch (470) and a noise level quantizer (440) in response to a multi-channel noise parameter, such as the overall average background noise level of the input signal. Then the individual channel gain values (455) are obtained from the particular gain table set in response to the individual channel signal-to-noise ratio estimate (235). Hence, each individual channel gain value is selected as a function of (a) the channel number, (b) the current channel SNR estimate, and (c) the overall average background noise level. The automatic gain selector further includes a gain smoothing filter (460) for smoothing these noise suppressio…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.