Abstract
We have designed an excitation part of the driving circuit of the fundamental mode orthogonal fluxgate (FG) to avoid an interference problem between fluxgates that may occur when individually operating fluxgates are placed closely. In the new design, three sensor heads are driven by a common excitation current while their outputs are processed separately to yield their own outputs. With magnetometers of this design we have built a 6ch FG array of a linear arrangement with the spacing of 3cm, as a step to a 6×6 fluxgate array. The excitation frequency was shared by two excitation circuits each of which provides a set of three sensor heads with the excitation current. Magnetocardiogram (MCG) was measured with the 6ch FG array by repeatedly sliding a top plate of the bed by 3cm that carrying a healthy volunteer lying on it. The distribution of the QRS complex observed on the 5×6 of the measurement points resembles that observed by a SQUID MCG measurement system.
