Architectural Analysis of a Novel Closed-Loop VCO-Based 1–1 Sturdy MASH Sensor-to-Digital Converter

摘要

This paper presents the architectural concept and analysis of a novel VCO-based highly-digital closed-loop system employing a single VCO, which can achieve second-order quantization noise shaping thanks to the use of a second loop in 1–1 SMASH configuration, while still ensuring high linearity thanks to the feedback loop. The architecture improves upon the VCO-based closed-loop system, which only achieves inherent first-order noise shaping. The basic operating principle of the architecture is described at system level. Based on frequency -domain models, a theoretical analysis is presented, which derives the STF and the NTF for both architectures. State-variable-based simulation results are presented, which confirm the theoretical analysis and the SONR improvement of the new architecture.