ADPCM Encoder/decoder with zero code suppression
US4542516A · kind A · utility
9Cited by
2References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 28, 1983 |
| Grant date | Sep 17, 1985 |
| Priority date | — |
| Expiry date | Nov 28, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B14/068
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An ADPCM encoding/decoding arrangement produces n-bit ADPCM codes which have 2.sup.n -1 possible codes, excluding the all-zeroes code. A range of error signals about zero is quantized by the encoder as a non-zero ADPCM code. In order to avoid such non-zero codes resulting in undesired changes of predictor coefficients of an adaptive predictor of the arrangement, updating of the predictor coefficients in dependence upon a reconstructed error signal derived from the ADPCM signal is inhibited when each such non-zero code occurs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.