Transmission of wideband speech signals
US5068899A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 1985 |
| Grant date | Nov 26, 1991 |
| Priority date | — |
| Expiry date | Apr 8, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/1688
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Speech signal components in a high band of frequencies between 4 and 8 kHz are transmitted via a digital transmission channel, which carries speech signal samples at frequencies below 4 kHz and sampled at a rate of 8 kHz, by replacing the least significant bit of the samples with bits of information derived from the high band by linear predictive coding. These information bits are transmitted in frames, each frame comprising a synchronizing bit and bits representing the power of and a set of filter coefficients for the high band signal components occurring in a period corresponding to the frame duration. Each such bit is transmitted redundantly three or six times in view of bit stealing techniques already used for signalling on digital transmission links. The resulting wideband speech signal transmission is compatible with existing limited bandwidth voice channel transmission arrangements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.