A slope adaptive delta modulator for VLSI signal processing systems

Abstract

A novel method of analog-to-digital (A/D) conversion utilizing a Slope Adaptive Delta Modulation approach which we will call Instantly Adaptive Delta Modulation (IADM), is described. This new system provides higher quality processable code than present modulators yet requires substantially reduced sampling rates. It displays a wide tolerance for variations in its component values and operates undisturbed in the presence of large amplitude dc or 60-Hz interference signals. An analysis of the frequency response and quantization noise characteristics of the system are presented. Specific designs for the component blocks demonstrate the compatibility of the system with present day CMOS technology. The compatibility of this system with VLSI technology makes it especially attractive for implementation in a monolithic audio-processing IC, such as a CODEC filter, or audio quality A/D converter.