3.3 V mixed-mode IC design using switched-current techniques for speech applications

Author

Kuo, T.-H. ; Lee, S.-Y. ; Lu, D.-J. ; Jih, T. ; Tsaur, J.-J.

Author_Institution

Dept. of Electr. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan

Volume

144

Issue

6

fYear

1997

fDate

12/1/1997 12:00:00 AM

Firstpage

367

Lastpage

374

Abstract

A low-cost, low-voltage, mixed-mode integrated circuit for speech applications is presented. The mixed-mode IC can directly preamplify speech signals with the aid of automatic gain control, convert amplified signals to 1-bit digital codes at 24 kbit/s, store the converted codes in memory, and replay the stored codes through an on-chip current-input voltage-output power amplifier. Switched-current techniques are used to implement a filter with a 3.4 kHz bandwidth and a 96 kHz sampling frequency, and also an adaptive delta modulator (ADM) with a 24 kHz sampling frequency. Measured dynamic range of the SI ADM combined with the SI filter is greater than 40 dB. This mixed-mode IC, operating with a 3.3 V supply voltage, was fabricated by a 1.5-μm single-poly single-metal CMOS process. The whole system has been tested using human voice and results show that it is highly suitable for low-cost speech applications

Keywords

CMOS integrated circuits; adaptive signal processing; automatic gain control; delta modulation; integrated circuit design; mixed analogue-digital integrated circuits; signal sampling; speech processing; switched current circuits; switched filters; 1.5 micron; 24 kbit/s; 3.3 V; 3.4 kHz; 96 kHz; AGC; SI filter; SI techniques; adaptive delta modulator; automatic gain control; code storage; current-input voltage-output power amplifier; digital codes; low cost speech applications; low-voltage operation; mixed-mode IC design; sampling frequency; single-poly single-metal CMOS process; switched-current techniques;

fLanguage

English

Journal_Title

Circuits, Devices and Systems, IEE Proceedings -

Publisher

iet

ISSN

1350-2409

Type

jour

DOI

10.1049/ip-cds:19971588

Filename

646821