Digital speech coder having improved vector excitation source
US4896361A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 6, 1989 |
| Grant date | Jan 23, 1990 |
| Priority date | — |
| Expiry date | Jan 6, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2019/0013
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An improved excitation vector generation and search technique (FIG. 1) is described for a code-excited linear prediction (CELP) speech coder (100) using a codebook memory of excitation code vectors. A set of M basis vectors v.sub.m (n) are used along with the excitation signal codewords (i) to generate the codebook of excitation vectors u.sub.i (n) according to a "vector sum" technique (120) of converting stored selector codewords into a plurality of interim data signals, multiplying the set of M basis vectors by the interim data signals, and summing the resultant vectors to produce the set of 2.sup.M codebook vectors. Only M basis vectors need to be stored in memory (114), as opposed to all 2.sup.M code vectors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.