发明名称 |
Noise Pre-Processor for Enhanced Variable Rate Speech Codec |
摘要 |
An enhanced noise pre-processor in a speech codec smoothes channel energy estimate moving toward a first smoothing constant if a prior signal to noise ratio estimates for more than five channels are above a threshold and toward a second smaller smoothing constant otherwise. Forming a signal to noise ratio estimate for each channel includes conditionally boosting if a signal energy estimate is more than a predetermined factor of a noise energy estimate and signal to noise ratio estimates are above a threshold for more than five channels. The estimated signal to noise ratio is conditionally modified if two long term prediction coefficients are above a predetermined factor. The estimated signal to noise ratio is not modified and a voice metric is set greater than a voice metric threshold upon matching templates corresponding to the fricative and nasal speech sounds. An adaptive minimum channel gain is chosen based on current signal to noise ratio estimate.
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申请公布号 |
US2007136056(A1) |
申请公布日期 |
2007.06.14 |
申请号 |
US20060608963 |
申请日期 |
2006.12.11 |
申请人 |
MOOGI PRATIBHA;GOUDAR CHANAVEERAGOUDA V |
发明人 |
MOOGI PRATIBHA;GOUDAR CHANAVEERAGOUDA V. |
分类号 |
G10L21/02 |
主分类号 |
G10L21/02 |
代理机构 |
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