Multi-pulse coding apparatus with a reduced bit rate
US4991215A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 13, 1989 |
| Grant date | Feb 5, 1991 |
| Priority date | — |
| Expiry date | Oct 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An input speech signal is converted into sampled data with a first sampling frequency in each of a plurality of analysis frames. The sampled data are produced as filtered data through a digital filter having a high cut-off frequency smaller than the highest frequency of the speech signal. The filtered data are decimated into decimated signals which are sampled at a second sampling frequency smaller than the first sampling frequency and which are used to develop multi-pulses representative of an exciting source information of the input speech signal. Each of the analysis frames is divided into a plurality of subframes. At most one multi-pulse is developed in one subframe and the other multi-pulses are subsequently developed for the subframes other than the subframe where the one multi-pulse has been developed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.