Speech coding method and device for implementing the improved method
US4464783A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1982 |
| Grant date | Aug 7, 1984 |
| Priority date | — |
| Expiry date | Apr 20, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/667
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
This improved speech signal Block Coded PCM (BCPCM) system reduces the number of bits allocated to transmitting the scale factor, thereby releasing bits for allocation to coding samples in the associated block of samples. The scale factor (c) is calculated for every 16 millisecond block of samples. However, the scale factor will be transmitted only once per 32 millisecond block if there is no significant difference between the two sequential values. The original speech signal is split into 16 frequency subbands, each subband initials sampled and 12-bit coded, then requantized in BCPCM at dynamically variable bit rates depending on the scale factor transmission rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.