Adaptive speech coder having code excited linear predictor with multiple codebook searches
US5717824A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 7, 1993 |
| Grant date | Feb 10, 1998 |
| Priority date | — |
| Expiry date | Dec 7, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2019/0013
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus determining codevectors in response to a speech signal include a first codebook member which stochastically determines the characteristics of a bi-pulse codevector representative of a target vector associated with the speech signal and for removing the bi-pulse codevector from the target vector thereby forming an intermediate target vector. A second codebook member stochastically determines the characteristics of a second bi-pulse codevector in response to the intermediate target vector. In one embodiment of the invention a third codebook member adaptively determines a first codeword in response to the target signal and forms another intermediate target signal and a fourth codebook member stochastically determines a second codeword in response to the intermediate target signal. Synthesized speech signals are determined from the first and second codevectors and from the first and second codewords formed from either the first and second codebook pairing or from the third and fourth codebook pairing. A comparator determines and chooses the synthesized speech signal having the least difference with the speech signal. The codewords or codevectors associated with th…
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