Digital Noise Coupled MASH Delta-Sigma Modulator

Abstract

This brief proposes digital noise coupling technique for multistage noise shaping Delta-Sigma modulator. In the proposed technique, the digital output of the second stage is fed to the input of the first stage quantizer with unit delay. After digital post-processing, the quantization noise of the first stage will be cancelled. The leaked quantization noise, caused by the mismatch between the analog and digital noise transfer functions, will be shaped by digital coupling. Hence, more robustness to circuit nonidealities such as the finite gain of amplifiers will be achieved, which is appropriate for low power and low voltage applications. Simulation results show the effectiveness of the proposed architecture.