Advancing Data Weighted Averaging Technique for Multi-Bit Sigma-Delta Modulators

Multibit sigma–delta modulators which employ the data weighted averaging (DWA) technique are plagued by baseband tone problems. The existing DWA-like techniques for solving these problems are categorized in this brief as tone-suppressing and tone-transferring techniques. Although tone-transferring techniques can achieve a better signal-to-noise-plus-distortion ratio than tone-suppressing techniques, they may behave unfavorably for input signals with dc components. A flexible DWA-like technique, designated as “advancing DWA” (ADWA), which can achieve both tone-suppressing and tone-transferring functions, is proposed. It can be configured as a tone-transferring technique by advancing the starting selection of the element array by a fixed step for the subsequent element selection cycle. Moreover, ADWA can also be configured as a tone-suppressing technique to reduce tones by randomly performing the advancing actions. Therefore, ADWA can be a reconfigurable technique that uses configuration settings from designers, or an auto-configurable technique that uses input signal detection schemes to set its configuration.