Comprehensive Compensation Scheme for Fetal Magnetocardiography Measurement

Fetal Magnetocardiography (fMCG) is a non-invasive technique for recording and analyzing the magnetic elements of the fetal cardiac cycle, emanating from the hearts' electrical activities. To improve the detection accuracy of fMCG, environmental noise suppression is essential. This paper presents a robust approach that combines an active compensation system with a SQUID gradiometer to suppress environmental noise. And proposed an evaluation method that can intuitively reflect the compensation effect. Initially, the sensor's operational environment was thoroughly assessed, leading to the adoption of targeted noise suppression strategies across various frequency bands. A three-axis Helmholtz coil-based compensation system was developed, achieving an impressive 25 decibel (dB) noise rejection in 100 Hz. Additionally, a second-order gradiometer effectively suppressed noise by 35 dB in the same frequency.