Near-instantaneous companding PCM involving accumulation of less significant bits removed from original data
US4633483A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 1984 |
| Grant date | Dec 30, 1986 |
| Priority date | — |
| Expiry date | Apr 2, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/3053
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A data transmission system combines a near-instantaneous companding system with PCM or DPCM transmission data. In the transmitting side, lower bits are removed from an original data, to form transmission data and are accumulated in an accumulator. When a carry is caused as a result of such accumulation, the carry is added to the transmission data. Thus, total amount of the original data can be transmitted to the receiving side, thereby to improve a transmission quality and to reduce quantizing-noise. When the removed bits are subject to an addition, it is determined whether an overflow occurs. When the overflow occurs, the addition is not performed and such a logic operation as to prevent the overflow is performed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.