A sigma-delta modulator for bio-applications

This paper presents a new concept of sigma-delta modulator (SDM) for biomedical applications. It combines switched-capacitor (SC) and switched-opamp (SOP) techniques. To Avoid signal distortion and nonlinear resistance in implementing the CMOS resistor of the SDM, an approach, replacing SC modulator with SOP modulator and reducing power consumption of the second-stage modulator, is utilized.