Method for generating additive combinations of PCM voice samples
US4757494A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 2, 1987 |
| Grant date | Jul 12, 1988 |
| Priority date | — |
| Expiry date | Nov 2, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/569
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method for generating additive combinations of PCM voice samples separates the samples into magnitude portions and sign portions. The magnitude portion of each PCM voice sample is converted from compressed PCM form to linear form. The magnitudes of the two voice samples, in linear form, along with their respective signs are added together to form a resultant linear value. If there is any overflow as a result of the addition, the resultant value is truncated so as not to exceed a maximum allowable value. The resultant value is then converted from linear form to compressed PCM form along with the proper sign. These steps are iterated for each possible value of the input PCM voice samples. These resultant values are stored in a storage medium for rapid on-line use by a switching system. Off-line generation of combined PCM samples saves system real time as compared to generating these combinations on-line in real time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.