Amplifiers – With semiconductor amplifying device – Including differential amplifier
Patent
1987-09-16
1989-01-17
Mullins, James B.
Amplifiers
With semiconductor amplifying device
Including differential amplifier
330 51, 330147, 330260, 330306, H03F 345
Patent
active
047990260
ABSTRACT:
A multifunction amplifier uses a finite transconductance amplifier to provide an amplifier with a high impedance input and a desired output impedance. A pair of appropriate polarity binary signals are summed to form a ternary signal which may be filtered by a filter circuit upon command. The ternary signal, filtered or unfiltered, is input to one input of a differential transconductance amplifier while a feedback signal via a feedback path from an output node of the finite transconductance amplifier is input to the other input. The outputs of the differential transconductance amplifier are equally amplified by a pair of output current gain amplifiers. A unity gain bias level shifter is provided between one of the differential outputs and one of the pair of output amplifiers. The output amplifiers combine the amplified output currents at the output node. The finite transconductance of the finite transconductance amplifier is determined by the emitter resistors of the differential transconductance and output amplifiers, and the desired output impedance is a function of a feedback resistor that forms the feedback path, an input resistor to the differential transconductance amplifier and the finite transconductance. A current switch connects a constant current source to the differential transconductance amplifier to provide current bias upon command, the desired output impedance appearing at the output node when the current source is conducting and an essentially infinite output impedance appearing at the output node when the current source is not conducting.
REFERENCES:
patent: 3517270 (1970-06-01), Dilley
patent: 3706936 (1972-12-01), Krohn
patent: 4532482 (1985-07-01), Noguchi
La Barge Steven B.
Stanger Leon J.
Gray Francis I.
Mullins James B.
The Grass Valley Group Inc.
LandOfFree
Multifunction amplifier does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multifunction amplifier, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multifunction amplifier will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2414746