A Study on the Modeling and Design of Sigma-Delta Modulator for High Precision ADC

With the continuous improvement of signal processing accuracy requirements in modern electronic systems, the demand for high-precision analog-to-digital converters (ADCs) is increasing. Sigma-Delta modulator, as the most important component of high-precision ADC, is widely used in high-quality audio, high-precision instrument measurement, and other fields due to its advantages of high precision, strong noise resistance, and low hardware cost. This article designs a discrete structure third-order four-bit high-precision Sigma-Delta modulator through modeling, with an oversampling rate set to 512. Under ideal conditions, the simulation results show that the SDNR reaches 152.7db and the ENOB is 25.24bits. After introducing non-ideal noise, the system performance has decreased. The simulation results show that the SDNR is as high as 124.5db and the ENOB is 20.39bits. This indicates that the design can achieve high-precision conversion and provide assistance for further research in the future.