Actively suppressing magnetic noise in bio-magnetic signals - subtracting weighted correction values from each signal

摘要

A biomagnetic signal transducer, with a number of gradiometers of the order 1 to N has field coils (11-N1) and compensation units (12-N2) oppositely wound. Coupling coils (13-N3) complete the circuit and interact with SQUID devices that are superconducting (14-N4). The outputs of the SQUID stages are coupled to an electronic circuit (15-N5) and inputs are provided to a weighting circuit (27) and a correction stage (28) that carries out subtraction of a weighted value from each channel. USE/ADVANTAGE - Electronic compensation of e.m. noise with lowest possible loss of signal.