Magnetic sensor 1 has MR elements 11A to 14A that are connected to each other. MR elements 11A to 14A belongs either to group G1 in which electric resistance increases when the magnetization direction of each free layer 26 is rotated a predetermined angle in a same direction, or to group G2 in which the electric resistance decreases when the magnetization direction of each free layer 26 is rotated the predetermined angle in the same direction. A variation of an output of magnetic sensor 1 due to an increase of the electric resistance of the electric resistance elements of one group and a variation of the output of magnetic sensor 1 due to a decrease of the electric resistance of the electric resistance elements of another group are cancelled out.

A full-polarization Faraday magnetic field sensor based on a Sagnac interference system and a modulation method are provided. The full-polarization Faraday magnetic field sensor includes a light source, an optical fiber coupler, a polarizer, a polarization beam splitter, a polarization controller, a magnetic field sensing unit, a detector and a polarization maintaining optical fiber. An optical signal is emitted by the light source, passes through the optical fiber coupler and the polarizer in sequence, and is divided into a clockwise path and an anticlockwise path by the polarization beam splitter. Angles between fast axis directions of the two polarization maintaining optical fiber loops and a polarization direction of the polarizer are respectively clockwise 45° and anticlockwise 45°. The two polarization maintaining optical fiber loops has opposite winding directions, a same diameter, and a same number of winding turns.

A magnetic position sensor comprises a first magnetic rod including a first end and a second end, and a second magnetic rod including a third end and a fourth end, the first end and the third end at a first distance, the second end and the fourth end at a second distance greater than the first distance. The magnetic position sensor further includes a magnet configured to travel relative to the first magnetic rod and the second magnetic rod along a first axis, and one or more magnetic sensors communicatively coupled to the magnet.

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).

An exemplary magnetic field measurement system includes a wearable sensor unit and a single controller. The wearable sensor unit includes a plurality of magnetometers and a magnetic field generator configured to generate a compensation magnetic field configured to actively shield the magnetometers from ambient background magnetic fields. The single controller is configured to interface with the magnetometers and the magnetic field generator.

An exemplary magnetic field measurement system includes a wearable sensor unit and a controller. The wearable sensor unit includes 1) a magnetometer comprising a photodetector and 2) a magnetic field generator configured to generate a compensation magnetic field configured to actively shield the magnetometer from ambient background magnetic fields. The controller is configured to interface with the magnetometer and the magnetic field generator and includes a differential signal measurement circuit configured to measure current output by the photodetector.

An exemplary magnetic field measurement system includes a wearable sensor unit that includes a magnetometer, a magnetic field generator configured to generate a compensation magnetic field configured to actively shield the magnetometer from ambient background magnetic fields, a twisted pair cable interface assembly electrically connected to the magnetometer, and a coaxial cable interface assembly electrically connected to the magnetic field generator.

An apparatus and a method for redundant measurements of a magnetic field originating from or influenced by a moveable object is described. The apparatus comprising at least one first magnetic field sensitive element measuring at least one magnetic field property of the magnetic field, wherein the at least one first magnetic field sensitive element is implemented on a first area of a semiconductor substrate, at least one second magnetic field sensitive element measuring at least one magnetic field property of the magnetic field, wherein the at least one second magnetic field sensitive element is implemented on a second area of said semiconductor substrate, and wherein the first and second areas are isolated from one another.