Telephone set in which an echo signal is effectively cancelled in spite of being provided with a plurality of sound producing units
US5699423A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1995 |
| Grant date | Dec 16, 1997 |
| Priority date | — |
| Expiry date | Mar 20, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/082
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a telephone set having a receiver (42) and a loudspeaker (39), a switch circuit (37) selects supply of a reception speech signal, transmitted from a counterpart section (60), to the receiver or the loudspeaker in response to a selection signal. A first adaptive echo canceller (43a) produces a pseudo echo signal with reference to the reception speech signal. A controller (44) controls operation of the first adaptive echo canceller in response to the selection signal to optimize the pseudo echo signal. A first digital adder (35a) carries out a particular calculation between the pseudo echo signal and a transmission speech signal, relating to the transmission sound supplied to a microphone (46). The adder produces a particular calculation result signal representative of a result of the particular calculation. In accordance with the particular calculation result signal, a transmission is carried out towards the counterpart section.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.