Telephones with talker sidetone
US5946391A · kind A · utility
76Cited by
5References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1996 |
| Grant date | Aug 31, 1999 |
| Priority date | — |
| Expiry date | Nov 22, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/6008
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A telephone, particularly a portable handset operable in a digital radio telephone system, has a sidetone gain circuit 28 which applies one of two levels of gain G1 G2 dependent on whether a detector 30 detects a high magnitude of input signal 14 corresponding to speech or a low level of input signal 14 corresponding to an idle condition. With varying magnitude of input signal 14, the gain switches between G1 and G2 dependent on two thresholds T1 and T2 of the input signal, the relationship including hysteresis to prevent unduly rapid switching.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.