Limiting maximum gain in duplex communications devices including telephone sets
US7092513B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 2004 |
| Grant date | Aug 15, 2006 |
| Priority date | — |
| Expiry date | Jul 16, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2420/07
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Duplex communication methods and systems with maximum gain limiting such as in telephone handsets and speaker phones are disclosed. The communications system such as a telephone set may generally include a digital signal processor (DSP) having a receive and transmit path in communication with a receiver and a transmitter, respectively, a volume amplifier for amplifying signals on the receive path, and a maximum gain limiter for determining a total return loss between the receive and transmit paths and for limiting a volume amplification level of the volume amplifier to a maximum depending on the total return loss. The maximum gain limiter determines the total return loss by maintaining a total loop gain for the telephone set at less than 0 dB to prevent unstable operation and howling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.