A Wide Dynamic Range Sigma-Delta Modulator for EEG Acquisition Using Randomized DWA and Dynamic-Modulated
Yongchun Han1,2, Wenhao Liu1,2, Xiangwei Zhang1,2
1Research and Development Center of Healthcare Electronics, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, China.
Sensors (Basel, Switzerland)
|January 8, 2023
Summary
This study introduces a novel sigma-delta modulator using dynamic-modulated scaling-down technology for enhanced electroencephalogram (EEG) acquisition. It achieves a wide dynamic range and high resolution, improving non-invasive brain monitoring.
Area of Science:
- Electrical Engineering
- Biomedical Engineering
- Signal Processing
Background:
- Non-invasive electroencephalogram (EEG) acquisition requires high-resolution and wide dynamic range signal processing.
- Existing sigma-delta modulators face challenges in handling large input offsets and achieving broad dynamic ranges simultaneously.
Purpose of the Study:
- To propose a discrete-time (DT) 2-order 4-bit sigma-delta modulator with a novel dynamic-modulated scaling-down (DM-SD) technology.
- To enhance the dynamic range (DR) and suppress large input offsets for improved EEG signal acquisition.
Main Methods:
- Design and implementation of a 180nm CMOS 2-order 4-bit sigma-delta modulator.
- Incorporation of a novel dynamic-modulated scaling-down (DM-SD) technology to expand input dynamic range and mitigate offsets.
- Performance evaluation through simulation and analysis of signal-to-noise and distortion ratio (SNDR), dynamic range, and power consumption.
Main Results:
- Achieved a Signal-to-Noise and Distortion Ratio (SNDR) of 118.1 dB for a 437.5 Hz input signal with a 1500 Hz signal bandwidth.
- Expanded the dynamic range (DR) to 126 dB through the proposed DM-SD technology.
- Realized a Schreier figure-of-merit (FoMs) of 177.8 dB with a power consumption of 1.6 mW.
Conclusions:
- The proposed discrete-time sigma-delta modulator with DM-SD technology effectively enhances dynamic range and resolution for EEG acquisition.
- The technology successfully suppresses large input offsets, a critical factor in non-invasive biological signal monitoring.
- The modulator demonstrates superior performance metrics, including a high FoMs, making it suitable for advanced biomedical applications.
