Audio AGC amplifier
US3991272A · kind A · utility
7Cited by
4References
10Claims
0Family size
Inventor
Key dates
| Filing date | Sep 8, 1975 |
| Grant date | Nov 9, 1976 |
| Priority date | — |
| Expiry date | Sep 8, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/3015
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An automatic gain control circuit for limiting the acoustical power to the receiver portion of a telephone operator's headset. The circuit provides means whereby the maximum level of acoustic energy output a telephone operator is subjected to is controlled to levels well below those where damage to the ear can occur. Features of the invention include the use of diodes in the feedback path of the an amplifier whereby DC currents control the conductivity of the diodes to control the amplifier gain, and a pair of such circuits in phase opposition serve to cancel control current effects on the signal path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.