Noise reduction system
US5012519A · kind A · utility
176Cited by
18References
10Claims
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Key dates
| Filing date | Jan 5, 1990 |
| Grant date | Apr 30, 1991 |
| Priority date | — |
| Expiry date | Jan 5, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2021/02168
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Noise in a speech-plus-noise input signal is suppressed by splitting the input signal into spectral channels and decreasing the gain in the each channel which has a low signal-to-noise ratio (SNR). A voice operated switch (VOX) acts to detect noise-only input to gate a background noise (input signal) estimator and also to gate a residual noise (output signal) estimator. The gain in each of the channels is controlled by the current value (a posteriori) input signal SNR estimate, modified by the prior value (a priori) input signal SNR estimate, and smoothed as a function of the residual (output noise signal) estimate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.