Speech coders with speech-mode dependent pitch lag code allocation patterns minimizing pitch predictive distortion
US5778334A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 1995 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Aug 2, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2019/0013
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A speech coding device capable of delivering a speech signal of excellent sound quality at a low bit rate is disclosed. The disclosed device is characterized by a method of calculating lag corresponding to pitch period and a speech signal coding method. Lag is calculated as follows: A speech signal is divided into frames; one frame is divided into a plurality of subframes; for each frame, subframes in which lag of a speech signal is expressed in the form of a differential relative to lag of a previous subframe and subframes in which lag is expressed in the form of an absolute value, i.e., the lag value itself, are established; a plurality of bit allocation patterns are established for each frame that allocate bits for expressing lag as an absolute value or a differential in each of the plurality of subframes; for each bit allocation pattern, pitch predictive distortion is calculated for every subframe; accumulated distortion is calculated by accumulating the pitch predictive distortion over a predetermined plurality of subframes in the frame; a bit allocation pattern is selected so as to minimize the accumulated distortion. The lags in the subframes of the selected pattern are dete…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.