MAGNETIC SENSOR DEVICE WITH FIELD GENERATORS AND SENSOR ELEMENTS

摘要

The invention relates to a magnetic sensor device (10) comprising (a) excitation wires (11, 13) for generating a magnetic excitation field (B) that magnetizes particles (2) in an investigation region (5), and (b) a magnetic sensor element, for example a GMR sensor (12), for detecting reaction fields (B') generated by the magnetized particles (2). The excitation wires (11, 13) and the GMR element (12) are driven by current pulses such that the average power dissipation is kept constant while the signal-to-noise ratio is optimized. The sampling frequency of said pulses is preferably larger than the thermal time constant (t) of the magnetic sensor device (10).