Stable Single-Bit Noise-Shaping Quantizer Based on ΣΔ Modulation and Successive Data Coding into Pre-Optimized Binary Vectors

摘要

This paper presents data coding techniques for a stable single-hit noise-shaping quantizer, which has a cascade structure of a multi-bit ΣΔ modulator and a binary interpolator. The binary interpolator chooses a pro-optimized binary vector for each input sample and successively generates the chosen binary vector as an output bit stream. The binary vectors can have different lengths. The paper also proposes two methods to evaluate and bound output errors of a binary interpolator. A multi-bit Σ? modulator is designed to cause no overload for all possible input signals whose amplitudes are bounded to a specified level, and thus the ΣΔ modulator rigorously guarantees the stability condition. In design examples, we have evaluated Signal-to-Noise and Distortion Ratios (SNDRs) and noise spectra and then confirmed that our stable quantizers can sharply shape output noise spectra.