Design and Implementation of a Fourth-Order Quadrature Band-Pass Delta-Sigma Modulator for Low-IF Receivers

Sung-Wook JUNG
Chang-Gene WOO
Sang-Won OH
Hae-Moon SEO
Pyung CHOI

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E83-A    No.12    pp.2649-2656
Publication Date: 2000/12/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Analog Signal Processing
delta-sigma modulation,  switched-capacitor circuits,  IF systems,  mixed analog-digital integrated circuits,  

Full Text: PDF>>
Buy this Article

The delta-sigma modulator (DSM) is an excellent choice for high-resolution analog-to-digital converters. Recently, a band-pass DSM has been a desirable choice for direct conversion of an IF signal into a digital bit stream. This paper proposes a quadrature band-pass DSM for digitizing a narrow-band IF signal. This modulator can achieve a lower total order, higher signal-to-noise ratio (SNR), and higher bandwidth when compared with conventional band-pass modulators. An experimental prototype employing the quadrature topology has been integrated in 0.6 µm, double-poly, double-metal CMOS technology with capacitors synthesized from a stacked poly structure. This system clocked at 13 MHz and digitized a 200 kHz bandwidth signal centered at 4.875 MHz with 100 dB of dynamic range. Power consumption is 190 mW at 5 V.