Circuit arrangement for controlling the volume range of a voice terminal
US5359653A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1992 |
| Grant date | Oct 25, 1994 |
| Priority date | — |
| Expiry date | Sep 9, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/085
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A circuit arrangement for dynamic control of a voice terminal apparatus contains a compander function. Instead of analog circuits for dynamic expander and compressor, a digital signal processor (DSP) is employed which, via a prestored characteristic (KL), assigns to individual average level values of the input signal, amplification factors which are fed to the amplifier (VS) located in the send path of the terminal apparatus. The stored characteristic can be shifted or replaced by another characteristic as a function of a noise average value, or from a receive average value obtained from the audible feedback signal. Thus, an amplification change in the send path is compensated in its action upon the audible feedback signal arriving via the receive path. In a further development, the circuits delivering the level average values are replaced by the digital signal processor, which carries out the functions assigned to these circuits by means of subprograms.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.