A vector magnetometer using a single Permalloy sensor with dual magnetic feedback

Magnetic feedback fields, applied in both hard and easy axis directions of a Permalloy sensor biased with a sinusoidal hard axis field and offset, pulsed easy axis field, allow the magnitude and direction of both orthogonal components of an external field to be determined. The two outputs from the feedback circuit, corresponding to these two components, are independent of sensitivity variations due to bias or temperature changes. The feedback circuit and sensor is a first order system with a corner frequency to sinusoidal inputs proportional to the hard axis bias frequency.<
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