A magnetic field detection apparatus includes a magnetoresistive effect element and a helical coil. The magnetoresistive effect element includes a magnetoresistive effect film extending in a first axis direction. The helical coil includes a parallel connection including first and second parts extending in a second axis direction inclined with respect to the first axis direction. The first and second parts are adjacent to each other in a third axis direction and coupled to each other in parallel. The helical coil is wound around the magnetoresistive effect element while extending along the third axis direction. The magnetoresistive effect film overlaps the first and second parts in a fourth axis direction orthogonal to the second and third axis directions. The helical coil is configured to be supplied with a current and thereby configured to generate an induction magnetic field to be applied to the magnetoresistive effect film in the third axis direction.

A magnetic sensor system includes two magnetic sensors that detect components in two directions of an external magnetic field, an additional magnetic field generation section, and a signal processing circuit. The additional magnetic field generation section is capable of generating two additional magnetic fields for use in measuring the sensitivities of the two magnetic sensors. The signal processing circuit includes a sensitivity measurement processing section and a detection signal correction processing section. The sensitivity measurement processing section measures the sensitivities based on data concerning changes in the detection signals of the two magnetic sensors when the additional magnetic field generation section is controlled to generate two additional magnetic fields. The detection signal correction processing section performs processing for reducing change components attributable to the two additional magnetic fields on the detection signals of the two magnetic sensors.

A system and method that can automatically select a frequency of a magnetic field in a magnetic tracking system. A magnetic tracking system emits an alternating magnetic field using a set of three frequencies. In the present approach, a transmitter is capable of generating multiple sets of three frequencies. A processor selects a first set of frequencies to use and causes the receiver to measure the amplitude of the magnetic field at those frequencies. In one embodiment, the frequency set having the lowest energy is selected. The processor then compares an estimated jitter at those frequencies to the actual jitter experienced using the frequencies. If the actual jitter exceeds the estimated jitter by a predetermined amount, the processor switches to a different set of frequencies and causes the receiver to measure the magnetic field at the new set of frequencies. The process may repeat using the additional sets of frequencies.

Various embodiments comprise a magnetic field compensation system. In some examples, the system comprises one or more coil drivers, magnetic field coils, and one or more magnetic field sensors. The one or more coil drivers supply a current to the magnetic field coils to generate a magnetic field. The magnetic field coils receive the current and generate the magnetic field. The magnetic field coils may be arranged in an array. The magnetic field coils individually comprise at least one coil trace pattern that encloses an area. The one or more magnetic field sensors measure the magnetic field generated by the magnetic field coils at a location proximate to the magnetic field coils.

A sensor device includes a current conductor designed to carry a measurement current, and a magnetic field sensor chip having a sensor element, wherein the magnetic field sensor chip is designed to detect a magnetic field at the location of the sensor element. The sensor device furthermore includes an encapsulation material, wherein the magnetic field sensor chip is encapsulated by the encapsulation material, and a soft magnet secured to the encapsulation material and designed to concentrate the magnetic field at the location of the sensor element. The magnetic field sensor chip and the soft magnet are galvanically isolated from one another by the encapsulation material.

The innovative concept described herein relates to a magnetic angle sensor system having a rotatable shaft, a permanent magnet coupled to the rotatable shaft, and a magnetic field sensor arranged opposite the permanent magnet, wherein the magnetic field sensor is configured to detect a magnetic field prevailing in its detection region. The magnetic angle sensor system comprises means for reducing and/or compensating for an inhomogeneous stray field component of a per se homogeneous external magnetic stray field.

A method for tracking performance of player including determining global direction of magnetic field at first court and computing first court specific data; providing rotation for rotating apparatus about spin axis via player, wherein rotating apparatus comprising XYZ-magnetic field sensor; measuring plurality of magnetic field values as function of time when rotating apparatus is rotating about spin axis; computing magnetic field component of magnetic field in direction of local body co-ordinate of spin axis of rotating apparatus; determining direction of spin axis using computed magnetic field component of magnetic field and determined global direction of magnetic field; determining player specific data comprising angle of spin axis with respect to horizontal ground plane and angle of shot direction with respect to horizontal component of spin axis; and calibrating and storing first court specific data and player specific data to track performance of player at first court.

We use the AC Hall effect to characterize a magnetic field at an unknown frequency (or frequencies). The current to the Hall sensor is driven at a known frequency f. The output Hall voltage is characterized in a frequency range from f1 to f2 (with f<f1<f2 and f2−f1<2f). This provides a measurement of the magnetic field in a frequency range from f1−f to f2−f. The resulting measurement of magnetic field spectral components is phase-independent and requires no prior knowledge of exact magnetic field frequency.

Devices for determining a state of a magnetic field-generating article are provided. In various embodiments, a device comprises: a single crystal diamond having a plurality of NV centers, the single crystal diamond configured to be disposed adjacent to a magnetic field-generating article, and configured to generate a fluorescent signal in response to being illuminated by a light source; a coherent light source configured to generate a light beam directed at the single crystal diamond; a microwave (MW) radiation source configured to irradiate the single crystal diamond with a MW signal; a magnetic field source configured to apply a bias magnetic field to the single crystal diamond; a photosensor configured to collect the fluorescent signal generated by the single crystal diamond; and a computing node operatively coupled to each of the coherent light source, the MW radiation source, the magnetic field source, and the photosensor.

Disclosed is a magnetometer architecture that couples one or more coils to a magnetic yoke to allow the reset of the magnetic yoke and one or more magnetic field sensors simultaneously after, for example, exposure to a large stray magnetic field. Also, disclosed is a magnetometer architecture that integrates separate magnetic pole pieces offset from the yoke that are each wound by a reset coil to allow reset of the one or more magnetic field sensors.