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

fYear

1986

fDate

16-18 Sept. 1986

Firstpage

89

Lastpage

91

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 (Â¿40Â°C - +85Â°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 Â¿). 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;

fLanguage

English

Publisher

ieee

Conference_Titel

Solid-State Circuits Conference, 1986. ESSCIRC '86. Twelfth European

Conference_Location

Delft, The Netherlands

Type

conf

Filename

5468314