Terminal station for telecommunication by wire
US5396549A · kind A · utility
1Cited by
6References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1993 |
| Grant date | Mar 7, 1995 |
| Priority date | — |
| Expiry date | Jul 16, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/76
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A telephone set includes an anti-sidetone circuit formed by a feedback loop having a filter in the feedback path. The feedback loop output is substantially equal to the signal produced at the set connection terminals by the microphone. Preferably the filter is composed of two sub-filters connected in cascade, formed of switched capacitors in an integrated circuit. An EEPROM control circuit can be included to permit easy programming during manufacture, to match a selected transmission line impedance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.