Title :
High-Performance Audio Amplifier with AGC Control and Signal Clipping for Portable Military Radio
Author :
Nauta, Henk C. ; Nordholt, Ernst H.
Author_Institution :
Delft University of Technology, Dept. of Electrical Engineering, P.O. Box 5031, 2600 GA DELFT, The Netherlands; Sagantec B.V., Croy 5a, 5653 LC EINDHOVEN, The Netherlands
Abstract :
An automatic-gain controlled audio amplifier and clipping amplifier, destinated for driving a transmitter in a portable military radio, is presented. Over the military temperature range (¿40°C - +85°C), the clipping level and the level where the AGC starts controlling the gain, drift by amounts no larger than 0.3dB and 0.09dB, respectively. This is the result of a novel system control loop, which largely eliminates offset and offset-drift in both the DC-coupled amplifiers whilst realising a large amount of transimpedance gain (3MEG ¿). Over the AGC control range (40dB) the output level only varies 0.2dB. The complete circuit, which also contains a microphone preamplifier and a digitally controlled power amplifier, has been integrated on an EXAR M-100 semicustom chip.
Keywords :
Automatic control; Circuits; Control systems; Digital control; Microphones; Preamplifiers; Radio control; Radio transmitters; Temperature control; Temperature distribution;
Conference_Titel :
Solid-State Circuits Conference, 1986. ESSCIRC '86. Twelfth European
Conference_Location :
Delft, The Netherlands
