Thoroughly revised and expanded to help readers systematically increase their knowledge and insight about Sigma-Delta Modulators. Sigma-Delta Modulators (SDMs) have become one of the best choices for the implementation of analogdigital interfaces of electronic systems integrated in CMOS technologies. Compared to other kinds of Analog-to-Digital Converters (ADCs), SDMs cover one of the widest conversion regions of the resolution-versus-bandwidth plane, being the most efficient solution to digitize signals in an increasingly number of applications, which span from high-resolution low-bandwidth digital audio, sensor interfaces, and instrumentation, to ultra-low power biomedical systems and medium-resolution broadband wireless communications.