Comparative Study between Continuous-Time Real and Quadrature Bandpass Delta Sigma Modulator for Multistandard Radio Receiver

This paper presents a continuous-time quadrature bandpass delta sigma modulator which offers significant theoretical and practical performance advantages over the alternative of a pair of traditional bandpass DeltaSigma modulator. The comparative study between the two types of modulator, real and quadrature, for multistandard radio receiver is based on the low-IF receiver architecture, which, with modern quadrature image reject mixers and strategic IF placement, offers a viable solution for realizing digital, monolithic receivers. 10^th order real, 3^rd and 5^th order quadrature bandpass modulator are designed and discussed for dual standard Bluetooth and WiFi.