Apparatus and method for providing a telephone user with control of the threshold volume at which the user's voice will take control of a half-duplex speakerphone conversation
US5857019A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1996 |
| Grant date | Jan 5, 1999 |
| Priority date | — |
| Expiry date | Jun 11, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/08
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An improved speakerphone that may be viewed as a modification of a conventional half-duplex speakerphone that includes transmit and receive attenuators for alternatively isolating either a speaker or a microphone from a phone line. The attenuators are controlled by a controller that compares a signal generated by the microphone with a signal received on the phone line to determine which of the transmit or receive attenuators should be turned on. In the present invention, a first variable gain amplifier is connected so as to amplify the signal generated by the microphone prior to the signal being connected to the controller, and a second variable gain amplifier is connected so as to amplify the signal received on the phone line prior to the signal being connected to the controller. The first and second variable gain amplifiers have adjustable gain controls that are connected such that the gain of the first variable amplifier is decreased when the gain of the second variable amplifier is increased and vice versa. The adjustable gain control of one of the adjustable gain amplifiers is accessible to the user of the speakerphone and allows the user to adjust the threshold at which his v…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.