Robust Biopotential Acquisition via a Distributed Multi-Channel FM-ADC.

Area of Science:

• Biomedical Engineering
• Analog Electronics
• Signal Processing

Background:

• Traditional biopotential acquisition systems often suffer from wire clutter and susceptibility to motion and electromagnetic interference (EMI).
• Existing multi-channel systems require complex wiring and numerous analog-to-digital converters (ADCs), increasing power consumption and form factor.
• Need for robust, wearable biopotential monitoring solutions with high dynamic range and low power.

Purpose of the Study:

• To develop and demonstrate an active electrode system for biopotential acquisition utilizing a distributed multi-channel FM-modulated analog front-end and ADC architecture.
• To eliminate wire clutter and enhance resilience to artifacts through FM signal transmission.
• To achieve significant power savings and a competitive figure of merit compared to existing methods.

Main Methods:

• Each electrode captures a biopotential signal and converts it into a unique frequency-modulated (FM) signal using a voltage-controlled oscillator (VCO).
• FM signals from multiple electrodes are aggregated onto a shared analog line.
• A gateway integrated circuit digitizes the composite FM signal for further processing.

Main Results:

• Demonstrated a six-channel operation with FM channels centered around 15 MHz.
• Achieved a usable dynamic range (DR) of over 100 dB, attributed to FM coding gain.
• Implemented the system in 65 nm silicon, achieving a figure of merit competitive with state-of-the-art approaches.

Conclusions:

• The proposed FM-modulated active electrode system offers a rugged, wearable form factor by eliminating traditional wire clutter.
• The system provides enhanced resilience to motion and EMI artifacts, along with significant power savings due to a single ADC for multiple channels.
• This approach presents a viable and competitive alternative for advanced biopotential acquisition systems.