A wearable audio device that includes an electro-acoustic transducer for creating audio output and a magnetometer system comprising a magnetic field sensor with an output, a temperature sensor that is configured to determine an internal device temperature, a processor, and memory. The magnetometer system is configured to derive from the magnetic field sensor output a directional heading of the Earth's magnetic field. The magnetometer system is further configured to compensate the magnetic field sensor output, wherein the compensation is temperature dependent. The memory is configured to store temperature-dependent compensation information. The magnetometer system is further configured to use the temperature sensor output to retrieve compensation information from the memory in order to compensate the magnetic field sensor output at the current temperature.

Head-mounted augmented reality (AR) devices can track pose of a wearer's head to provide a three-dimensional virtual representation of objects in the wearer's environment. An electromagnetic (EM) tracking system can track head or body pose. A handheld user input device can include an EM emitter that generates an EM field, and the head-mounted AR device can include an EM sensor that senses the EM field (e.g., for determining head pose). The generated EM field may be distorted due to nearby electrical conductors or ferromagnetic materials, which may lead to error in the determined pose. Systems and methods are disclosed that measure the degree of EM distortion, as well as correct for the EM distortion. The EM distortion correction may be performed in real time by the EM tracking system without the need for additional data from imaging cameras or other sensors.

A wearable audio device that includes an electro-acoustic transducer for creating audio output and a magnetometer system comprising a magnetic field sensor with an output, a temperature sensor that is configured to determine an internal device temperature, a processor, and memory. The magnetometer system is configured to derive from the magnetic field sensor output a directional heading of the Earth's magnetic field. The magnetometer system is further configured to compensate the magnetic field sensor output, wherein the compensation is temperature dependent. The memory is configured to store temperature-dependent compensation information. The magnetometer system is further configured to use the temperature sensor output to retrieve compensation information from the memory in order to compensate the magnetic field sensor output at the current temperature.

A current sensor system includes a plurality of conductors, each having a first major surface, a second major surface opposite the first major surface, and an aperture extending from the first major surface through a thickness of the conductor to the second major surface. Each of the plurality of conductors is configured to carry a current and wherein the apertures of each of the plurality of conductors are aligned with a common reference line. The current sensor system further includes a plurality of current sensors, each positioned at least partially in the aperture of a respective conductor and including one or more magnetic field sensing elements.

A stress compensation control circuit of the present invention is provided which is capable of using a compensation error similar to that at room temperature even at a high temperature and reducing the area of a chip for a semiconductor sensor as compared with the related art. The stress compensation control circuit compensates for a change in detection sensitivity due to a stress to be applied to the semiconductor sensor. The stress compensation control circuit includes a stress compensation voltage generating circuit generating a stress compensation voltage corresponding to the applied stress in accordance with a difference between changes in transconductance due to stresses in a first depletion transistor and a first enhancement transistor, and performs compensation for the detection sensitivity in correspondence to the stress applied to the semiconductor sensor.

Provided is a current sensor having variable tuning precision capability depending on an amount of a current to be measured, a system state and the like. In the present disclosure, the current measurement apparatus having variable tuning precision capability does not separately require a current sensor measuring a small current with high precision and a current sensor stably measuring a large current without saturation. In the present disclosure, a single current measurement apparatus may vary current measurement precision depending on a current magnitude and the like, and may thus measure the small current with the high precision and stably measure the large current without saturation.

An exemplary magnetic field measurement system includes a wearable sensor unit and a single controller. The wearable sensor unit includes a plurality of magnetometers. The single controller is configured to generate a single clock signal and use the single clock signal to drive one or more components within the magnetometers.

An exemplary controller may include a single clock source configured to generate a single clock signal used to drive one or more components within a plurality of magnetometers and a plurality of differential signal measurement circuits configured to measure current output by a photodetector of each of the plurality of magnetometers.

An apparatus (10) for checking a component (30) is disclosed. The apparatus (10) comprises a sample holder (20) with a module (28) for receiving at least one component (30), at least one magnetic field generator (60a, 60b, 60c) for generating a magnetic field around the module (28), an inlet (40) for feeding a tempered medium into the module (25), and an outlet (45) for discharging a tempered medium from the module (28).

A field-sensor device comprises first and second field sensors disposed in corresponding different first and second orientations, each responsive to an external field to produce corresponding first and second sensor signals. One of or both the first and second sensor signals are converted to equivalent comparable sensor signals in a common orientation and compared to determine a faulty field sensor. If a faulty field sensor is determined, a faulty sensor signal is produced or, if a faulty sensor is not determined, an output sensor signal responsive to the first, second or comparable sensor signals is produced. Evaluation of the direction of differences between the comparable sensor signals can determine which of the first and second field sensors is faulty.