Reduced codebook search arrangement for CELP vocoders
US5173941A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 1991 |
| Grant date | Dec 22, 1992 |
| Priority date | — |
| Expiry date | May 31, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2019/0014
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A new way of CELP coding speech simplifies the recursive loop used to poll code adaptive book vectors by reducing the number of autocorrelation operations that must be performed with the K vectors of the codebook each having N entries. Autocorrelation is initially performed for only a small number P<<N autocorrelation coefficients in each codebook vector and the values found are used to scan through all the codebook vectors looking for those S vectors (S<K) which give the best match to the input speech. The autocorrelation function for the S vectors is then recalculated for R entries (P<R.ltoreq.N) in the codebook vectors to determine which of the S codebook vectors and associated gain gives the best match to the input speech.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.