Systems and techniques for a detecting a magnetic target that reduce output signal jitter are disclosed. A system includes a magnetic target. The magnetic target has a plurality of regions having juxtaposed edges and opposing ends. Adjacent ones of the plurality of regions have different magnetic polarities. The magnetic target includes a first magnetic strip, having a first magnetic polarity disposed at one end of the regions, and a second magnetic strip having a second magnetic polarity opposite to the first magnetic polarity disposed at a second end of the regions to generate a magnetic bias across at least a portion of the regions. The system includes at least one magnetic field sensing element placed in proximity to the magnetic target and configured to produce an output signal responsive to the magnetic target.

Systems and techniques for a detecting a magnetic target that reduce output signal jitter are disclosed. A system includes a magnetic target. The magnetic target has a plurality of regions having juxtaposed edges and opposing ends. Adjacent ones of the plurality of regions have different magnetic polarities. The magnetic target includes a first magnetic strip, having a first magnetic polarity disposed at one end of the regions, and a second magnetic strip having a second magnetic polarity opposite to the first magnetic polarity disposed at a second end of the regions to generate a magnetic bias across at least a portion of the regions. The system includes at least one magnetic field sensing element placed in proximity to the magnetic target and configured to produce an output signal responsive to the magnetic target.

A system for suppressing low frequency noise of magnetoresistive sensors, includes a device for measuring a magnetic field, the device including at least one magnetoresistive sensor, the magnetoresistive sensor having a first sensitivity at a first operating point and a second sensitivity at a second operating point, the sensitivity at the second operating point being low or zero; a modulator configured to switch the at least one magnetoresistive sensor from the first operating point to the second operating point; and a signal processor for processing the signal derived from the device for measuring a magnetic field.

A method for operating a magnetic field sensor and an associated magnetic field sensor system. The method includes: detecting an output signal of the magnetic field sensor that describes a magnetic field detected by the magnetic field sensor; establishing an adaptive filter function of an adaptive filter based on a model that describes an influence of specific objects on the output signal; filtering the output signal with the aid of the adaptive filter; ascertaining a deviation between the output signal and the output signal filtered with the aid of the adaptive filter; and detecting a presence of an object to be detected, based on the ascertained deviation.

A method for operating a magnetic field sensor and an associated magnetic field sensor system. The method includes: detecting an output signal of the magnetic field sensor that describes a magnetic field detected by the magnetic field sensor; establishing an adaptive filter function of an adaptive filter based on a model that describes an influence of specific objects on the output signal; filtering the output signal with the aid of the adaptive filter; ascertaining a deviation between the output signal and the output signal filtered with the aid of the adaptive filter; and detecting a presence of an object to be detected, based on the ascertained deviation.

A torsion bar of a torque detection device converts torque applied between an input shaft and an output shaft to a torsional displacement. A pair of yokes is secured to the output shaft, and forms a magnetic circuit in a magnetic field of a multipolar magnet secured to the input shaft. A magnetic flux guide member has a main body facing the yoke to guide magnetic flux of the magnetic circuit. A magnetic sensor is placed at an extension, and detects magnetic flux guided by the magnetic flux guide member. The magnetic flux guide member is configured to allow magnetic permeance per unit area between the magnetic flux guide member and the yoke to be greater at a location in the main body from which the extension is branched, than at a circumferential end portion of the main body.

A magnetic field detection sensor includes a magneto-impedance element configured to make use of the magneto-impedance effect, and a negative-feedback bias coil configured to apply a bias magnetic field to the magneto-impedance element. The magnetic field detection sensor is configured to detect an external magnetic field based on an output obtained by applying an alternating-current to the magneto-impedance element. The magneto-impedance element includes a non-magnetic substrate, and a magnetic thin-film that is provided on a surface of the non-magnetic substrate. The magnetic field detecting direction matches the longitudinal direction of the magneto-impedance element, and the magnetic thin-film is configured to have a magnetic anisotropy such that a direction of an axis of easy magnetization thereof matches the magnetic field detecting direction.

A method for verifying an operation of a Hall-effect sensor without an applied magnetic field. The method can include providing a bias signal to a first pair of terminals of a Hall-effect element, applying a Hall current signal to a second pair of terminals of the Hall-effect element, measuring a Hall output voltage across the second pair of terminals and comparing the measured Hall output voltage to an expected Hall output voltage that would be provided by a corresponding applied magnetic field.

Electronic equipment can include an equipment body and a magnetic sensor apparatus assembled to the equipment body. The magnetic sensor apparatus can be provided with at least two magnetic field detectors. Any two magnetic field detectors sense a magnetic field respectively in two different sensing directions. A control circuit sends a sensor signal to a motherboard only when each magnetic field detector senses, in a respective sensing direction, external magnetic induction of no less than a respective preset threshold corresponding to the each magnetic field detector. The motherboard sends a control signal to control the equipment body according to the sensor signal.

Electronic equipment can include an equipment body and a magnetic sensor apparatus assembled to the equipment body. The magnetic sensor apparatus can be provided with at least two magnetic field detectors. Any two magnetic field detectors sense a magnetic field respectively in two different sensing directions. A control circuit sends a sensor signal to a motherboard only when each magnetic field detector senses, in a respective sensing direction, external magnetic induction of no less than a respective preset threshold corresponding to the each magnetic field detector. The motherboard sends a control signal to control the equipment body according to the sensor signal.