Multi-bit sigma-delta modulation and its application in high-resolution analog-to-digital and digital-to-analog data conversions.

摘要

It has been shown that a multi-bit sigma-delta modulator improves the stability characteristics with an increased input signal range over its one-bit counterpart. This improvement facilitates a trade-off between input signal range and baseband quantization noise suppression. Therefore, a multi-bit sigma-delta data converter can achieve a given signal-to-noise ratio performance objective with a lower oversampling ratio (OSR) and/or lower modulation order than an one-bit converter, resulting in significant reduction of power dissipation and noise coupling from digital to analog circuits as well as ease of circuit design in the overall system. The main problem with multi-bit sigma-delta converters, however, is the internal multi-bit D/A process which leads to distortion and noise effects in the overall converter.;The first part of this thesis attempts to illustrate the principles of multi-bit sigma-delta modulation and its enhanced stability characteristics and other advantages over its one-bit counterparts. The second part demonstrates the design and implementation of a highly linear switched-capacitor multi-bit DAC, which is incorporated into a 4-th order multi-bit sigma-delta D/A converter that achieves 92 dB dynamic range and less than