Gain control circuit
US4134078A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 1977 |
| Grant date | Jan 9, 1979 |
| Priority date | — |
| Expiry date | Aug 9, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G1/0052
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A gain control circuit comprising a pair of transistors constituting a differential amplifier, and a pair of resistors each connected to the emitter of one of the transistors and having a sufficiently great resistance value compared with 1/gm of the transistor in the transistor operating range, the resistors being connected to a common regulated current supply to supply the halves of control current from the regulated current supply to the respective transistors, a pair of diodes are connected to the collectors of the respective transistors as a load, and a first variable resistor means is disposed in the current path traced from the diodes to the regulated current supply via the transistors and resistors for compensating fluctuation of the diffused resistance of the diodes. Further, a second variable resistor means is disposed in the base bias circuit for the transistors for compensating fluctuation of the base-emitter voltage of the transistors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.