Self-adaptive loop for external disturbance reduction in differential measurement set-up

TL;DR

This paper introduces a digital, self-adaptive feedback system that actively reduces common-mode magnetic disturbances in multi-sensor differential measurement setups, significantly improving noise performance.

Contribution

It presents a novel digital feedback approach using FPGA technology for automatic adaptation, achieving over 50 dB common-mode disturbance attenuation.

Findings

Attains >50 dB common-mode disturbance reduction

Reduces differential noise floor by a factor of 10

Operates effectively across the entire spectral range of interest

Abstract

We present a method developed to actively compensate common-mode magnetic disturbances on a multi-sensor device devoted to differential measurements. The system uses a field-programmable-gated-array card, and operates in conjunction with a high sensitivity magnetometer: compensating the common-mode of magnetic disturbances results in a relevant reduction of the difference-mode noise. The digital nature of the compensation system allows for using a numerical approach aimed at automatically adapting the feedback loop filter response. A common mode disturbance attenuation exceeding 50 dB is achieved, resulting in a final improvement of the differential noise floor by a factor of 10 over the whole spectral interval of interest.