A comparison of dithered and chaotic sigma-delta modulators

Abstract

Recent work has shown that higher order single-bit sigma-delta modulators suffer from low-level artifacts such as idle tones and noise modulation. Techniques that have been proposed to reduce or eliminate these errors include the application of dither inside the 1-bit quantizer loop and selecting a loop filter that makes the modulator chaotic. These two approaches are compared with regard to efficacy by simulating high-resolution sigma-delta modulators suitable for audio-conversion applications.