Title :
A universal telephone audio circuit with loudhearing and handsfree operation in CMOS technology
Author :
Hayat-Dawoodi, Kambiz ; Alminde, Oluf ; Kunc, Vinko ; Pauritsch, Manfred
Author_Institution :
Austria Mikro Syst. Int. AG, Unterpremstatten, Austria
Abstract :
A first CMOS chip, containing line interface/speech, power extraction, loudhearing, handsfree, DC/DC converter and ringer amplifier in a 28 pin package powered only from the line, is presented. The chip provides an enhanced anti-Larsen circuit to prevent acoustic howling in loudhearing mode and a revolutionary “handsfree mode” voice control system which is virtually independent of any background noise and works in a dynamic half duplex as close to full duplex as the acoustic loop gain allows. This paper describes the architectural features of the system and the design of the main building blocks of the integrated circuit
Keywords :
CMOS integrated circuits; audio systems; gain control; interference suppression; mixed analogue-digital integrated circuits; telephone interference; telephone sets; telephony; 28 pin package; CMOS chip; CMOS technology; DC/DC converter; acoustic howling prevention; anti-Larsen circuit; dynamic half duplex; handsfree operation; integrated circuit; line interface; loudhearing; power extraction; ringer amplifier; universal telephone audio circuit; voice control system; Attenuation; Background noise; CMOS technology; Circuits; Control systems; Loudspeakers; Microphones; Speech; Telephony; Working environment noise;
Conference_Titel :
European Design and Test Conference, 1995. ED&TC 1995, Proceedings.
Conference_Location :
Paris
Print_ISBN :
0-8186-7039-8
DOI :
10.1109/EDTC.1995.470411
