Abstract: A local nonlinear feedback loop (LNFL) technique and a sigma-delta modulator (SDM) for promoting highly stable oversampling using the LNFL technique. Not only can gain mismatch of the sigma-delta modulator be minimized, but the overload of the later stage sigma-delta modulator can also be resolved without sacrificing the signal noise ratios (SNR) of the overall system. Moreover, using the local nonlinear feedback loop technique of this invention attenuates the voltage signal of the sigma-delta modulator, therefore decreasing the power consumption of the overall sigma-delta modulator system.

Abstract: Based on the recently developed MASH (multistage noise shaping) architecture, an improved architecture--uni-MASH which employs the time-division concept for architecture and circuit reuse is proposed. An oversampling sigma-delta modulator having uni-MASH architecture uses a single stage of time- and capacitor-integrator in lieu of multiple stages of integrators, digital-to-analog converters and quantizers used in the MASH architecture. Uni-MASH retains robust stability and high-ordered noise shaping factor of MASH's virtues.