Circuit and method of reducing sidetone in a receive signal path
US5649008A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 1994 |
| Grant date | Jul 15, 1997 |
| Priority date | — |
| Expiry date | Aug 2, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/08
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A cordless telephone has receive (12) and transmit (14) signal paths for passing voice signals. Sidetones normally appear in the receive signal path from the near party's voice. A signal strength comparator (34) monitors the transmit signal path and the receive signal path and asserts a gain control signal when the transmit path signal strength exceeds a threshold set to a predetermined value below the receive path signal strength. The gain control signal decreases the gain (42) in the receive signal path to reduce undesirably loud sidetones in the speaker earpiece. When the transmit path signal strength is less than the predetermined threshold, the gain control signal is not asserted allowing maximum amplification in the receive signal path as the sidetone is sufficiently small as to not interfere with the main received voice signal, or otherwise become noticeably loud in the speaker earpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.