Voice switch for hands free communication apparatus
US4319086A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 23, 1980 |
| Grant date | Mar 9, 1982 |
| Priority date | — |
| Expiry date | Jun 23, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/10
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
First syllable clipping typically associated with simple control circuits in hands free telephony, is substantially reduced by using a voice switch with non-linear response characteristics. The voice switch includes field effect devices in transmit and receive variolossers for providing hands free operation in communication apparatus. The field effect devices are non-linear in their response to a control voltage, and are thus controllable to provide rapid switching from an idle mode of operation, to an opposite mode of operation. The control circuit generates a control signal for operating the voice switch in response to a.c. signals in a microphone circuit connected with a transmit path and in response to a.c. signals in a loudspeaker circuit connected with a receive path. A circuit including another field effect device similar to the above mentioned field effect devices, is responsive to the control signal for generating a control voltage for controlling attenuation introduced in the transmit and receive paths by the respective variolossers. This circuit generates the control voltage having first and second limits. The first limit corresponds to operation of the voice switch in a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.