Multi-rate voice encoding method and device
US4965789A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1989 |
| Grant date | Oct 23, 1990 |
| Priority date | — |
| Expiry date | Mar 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2019/0011
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The voice signal s(n) is filtered through a short-term predictive filter (13) tuned with PARCOR derived coefficients computed over a pre-emphasized s(n), said filter (13) providing a short-term residual r(n). Said r(n) signal is then processed through a first Cod-Excited/Long-Term Predicative coder providing first couples of table address and gain data (k1, gl)'s. An error signal r'(n) is then derived by subtracting coded/decoded data from uncoded data. Then said error signal is processed through a second Code-Excited/Long-Term Predictive coder providing second couples of data (k2, g2)'s. Full rate coding is achieved by multiplexing both couples (k1, gl)'s and (k2, g2)'s into a multi-rate frame; while switching to a lower rate is achieved through a mere delation of (g2, k2)'s from the full rate frame.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.