Development of a one dimensional fluxgate array and its application to magnetocardiogram measurements

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 6 ch FG array of a linear arrangement with the spacing of 3 cm, 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 6 ch FG array by repeatedly sliding a top plate of the bed by 3 cm 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.