A second-order sigma-delta modulator with built-in VGA to improve SNR and harmonic distortion

Author

Li, Xiaopeng ; Ismail, Mohammed

Author_Institution

Analog VLSI Lab., Ohio State Univ., Columbus, OH, USA

fYear

1999

fDate

4-6 Mar 1999

Firstpage

376

Lastpage

379

Abstract

A modified architecture of the second-order switched capacitor modulator is proposed. A simple four-transistor variable gain attenuator is included in the architecture which continuously adjusts the reference voltage of the quantizer feedback. This improves the output SNR for small signal input and reduces the harmonic distortion for large signal input. Simulation results show that it achieves higher dynamic range and lower harmonic distortions compared with the traditional architecture

Keywords

attenuators; circuit feedback; harmonic distortion; quantisation (signal); sigma-delta modulation; switched capacitor networks; SNR; built-in VGA; dynamic range; four-transistor variable gain attenuator; harmonic distortion; output SNR; quantizer feedback; reference voltage; second-order sigma-delta modulator; second-order switched capacitor modulator; Analog-digital conversion; Attenuators; Delta-sigma modulation; Dynamic range; Feedback; Gain; Harmonic distortion; Operational amplifiers; Signal to noise ratio; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

VLSI, 1999. Proceedings. Ninth Great Lakes Symposium on

Conference_Location

Ypsilanti, MI

ISSN

1066-1395

Print_ISBN

0-7695-0104-4

Type

conf

DOI

10.1109/GLSV.1999.757460

Filename

757460