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.

Adjusting of calibration parameters for a sensor. The adjusted calibration parameters may be used to correct the raw data of the sensor. It is provided to calculate new calibration parameters only when accuracy of the calibration parameters currently available is no longer adequate, and suitable measurement data are available for a recalibration of the sensor. Otherwise, the components necessary for calibrating the sensor data may be deactivated in order to reduce energy consumption.

A magnetic sensor includes first to fourth resistor sections and a plurality of MR elements. Each of the plurality of MR elements belongs to any of first to fourth groups. The first to fourth groups are defined based on the areas of top surfaces of the MR elements. The first resistor section, the second resistor section, the third resistor section, and the fourth resistor section are constituted of the first group, the second group, the third group, and the fourth group, respectively; the second group, the first group, the fourth group, and the third group, respectively; the first group, the fourth group, the third group, and the second group, respectively; or the third group, the second group, the first group, and the fourth group, respectively.

Sensor modules for measuring parameters such as magnetic fields, tilts, orientation, or other parameters in high resolution in three orthogonal axes using single-axis sensor arrays are disclosed.

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.

In one aspect, a magnetic field sensor includes a plurality of tunneling magnetoresistance (TMR) elements that includes a first TMR element, a second TMR element, a third TMR element and a fourth TMR element. The first and second TMR elements are connected to a voltage source and the third and fourth TMR elements are connected to ground. Each TMR element has a pillar count of more than one pillar and the pillar count is selected to reduce the angle error below 1.0°.

The present disclosure provides: a magnetoresistive element having a large magnetoresistance change ratio (MR ratio); and a magnetic sensor, a reproducing head and a magnetic recording and reproducing device.

The present disclosure generally relates to a Wheatstone bridge array that has four resistors. Each resistor includes a plurality of TMR films. Each resistor has identical TMR films. The TMR films of two resistors have reference layers that have an antiparallel magnetic orientation relative to the TMR films of the other two resistors. To ensure the antiparallel magnetic orientation, the TMR films are all formed simultaneously and annealed in a magnetic field simultaneously. Thereafter, the TMR films of two resistors are annealed a second time in a magnetic field while the TMR films of the other two resistors are not annealed a second time.

A system is provided for detecting a radio frequency signal. The system includes a dielectric platform, a first SQUID array, a second array of SQUIDs and a processing component. The dielectric platform has a first planar surface and a second planar surface that is disposed at an angle relative to the first planar surface. The first array of SQUIDs is disposed on the first planar surface and can output a first detection signal based on the radio frequency signal. The second array of SQUIDs is disposed on the second planar surface and can output a second detection signal based on the radio frequency signal. The processing component can determine a first plane from which the radio frequency signal is transmitting based on the first detection signal and the second detection signal.

The present disclosure generally relates to a Wheatstone bridge array that has four resistors. Each resistor includes a plurality of TMR films. Each resistor has identical TMR films. The TMR films of two resistors have reference layers that have an antiparallel magnetic orientation relative to the TMR films of the other two resistors. To ensure the antiparallel magnetic orientation, the TMR films are all formed simultaneously and annealed in a magnetic field simultaneously. Thereafter, the TMR films of two resistors are annealed a second time in a magnetic field while the TMR films of the other two resistors are not annealed a second time.