Kyushu University

Takao Yamauchi

Ichiro Sasada

An apparatus for measuring a weak magnetic field in a background D.C. magnetic field such as the earth's magnetic field or the like includes a magnetic pickup portion that is supported by a support mechanism which does not impede minute movement in the x- and y-axis direction. A pair of A.C. linear gradient magnetic fields whose directions of gradients are parallel to the x-axis and y-axis, respectively, are used for obtaining reference signals for sensing the position of the pickup portion. The frequencies of the A.C. linear gradient magnetic fields are set to be sufficiently higher than the frequency of the weak magnetic field that is to be measured. The A.C. linear gradient magnetic fields are provided by A.C. current flowing in two pairs of linear conductors which are perpendicular to each other.

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Kitakyushu, Japan

Takao Yamauchi