Title :
A precision control circuit for variable-gain amplifiers
Author :
Ciubotaru, Alexandru A.
Author_Institution :
Dept. of Electr. Eng., Texas Univ., Arlington, TX, USA
fDate :
9/1/1996 12:00:00 AM
Abstract :
The author describes a circuit that precisely controls the gain of one or more single-ended amplifiers by means of a corresponding number of Gilbert quads. The circuit employs a configuration consisting of a differential pair with two negative feedback loops and is used in conjunction with a precision potentiometer to generate a DC gain-control voltage as a function of its setting. The gain-control characteristic accurately mimics the potentiometer´s function of resistance versus wiper position to achieve a control range in excess of 55 dB. Experimental results are provided for the frequency response and the gain-control characteristic of the amplifiers
Keywords :
compensation; feedback amplifiers; frequency response; gain control; Gilbert quads; differential pair; frequency response; gain-control characteristic; negative feedback loops; precision control circuit; precision potentiometer; single-ended amplifiers; variable-gain amplifiers; Control systems; DC generators; Feedback circuits; Frequency response; Gain control; Negative feedback loops; Operational amplifiers; Potentiometers; Signal processing; Voltage control;
Journal_Title :
Circuits and Systems I: Fundamental Theory and Applications, IEEE Transactions on
