Companding of voice signal for simultaneous voice and data transmission
US5559791A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 14, 1993 |
| Grant date | Sep 24, 1996 |
| Priority date | — |
| Expiry date | Jun 14, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/3483
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a simultaneous voice and data communications system, a voice signal is added to a data signal before transmission over the public switched telephone network (PSTN). In particular, in every signaling interval, a signal point is selected for transmission as a function of both the voice signal and the data signal. Since the voice signal is effectively offset by the data signal, compandors normally found in the PSTN are not effective in improving the signal to noise ratio of the transmitted voice and data signal. Therefore, the voice signal is additionally companded in the transmitter before transmission over the PSTN. This additional companding by the transmitter improves the signal to noise ratio of the combined voice and data signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.