An interference type optical magnetic field sensor device 1 has a light emitter 10 emitting first linearly polarized light, a first optical element 30 emitting a first linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave with respect to incident the first linearly polarized light, and emitting a second linearly polarized light with respect to incident third linearly polarized wave and a forth linearly polarized wave orthogonal to the third linearly polarized wave, a magnetic field sensor element 50 disposed at least a portion thereof within a predetermined magnetic field an optical path unit 40 connected to the first optical element and the magnetic field sensor element, and having a first optical path propagating the first linearly polarized wave and the forth linearly polarized wave, and a second optical path propagating the second linearly polarized wave and the third linearly polarized wave, a detection signal generator 60 outputting a detection signal by separating the second linearly polarized light into an S polarization component and a P polarization component, converting the S polarization component and the P polarization component into an electric signal, and an optical branching element 20 transmitting the first linearly polarized light to the first optical element, and branching the second linearly polarized light to the detection signal generator, wherein the magnetic field sensor element emits the first linearly polarized wave and the second linearly polarized wave as incident light, and emits the third linearly polarized wave with respect to the first linearly polarized wave and the forth linearly polarized wave with respect to the second linearly polarized wave as return light.

Axial magnetic flux sensors are described. The axial magnetic flux sensors comprise multiple substrates with conductive traces on them in some embodiments, and in other embodiments a single substrate or no substrate. When multiple substrates are provided, the substrates couple together such that the conductive traces connect to form a coil. The coil may be a continuous, multi-loop coil. When the substrates are coupled together, they may define an opening to accommodate a shaft or other piece of equipment.

The present invention relates to a magnetic sensor based on a Wheatstone bridge and a manufacturing method thereof. The magnetic sensor according to an embodiment includes a magnetic field sensing unit that is provided with a plurality of magneto resistors forming a resistance bridge, a magneto resistor monitoring unit that monitors resistance values of the plurality of magneto resistors, and an offset adjusting unit that adjusts a resistance value of a thin film variable resistor connected to at least one terminal among a plurality of current terminals provided in the resistance bridge based on the monitoring result of the resistance values.

In one aspect, an angle sensor includes magnetic-field sensing elements that include a first pair, a second pair, a third pair and a fourth pair of magnetic-field sensing elements; and processing circuitry configured to determine an angle of a rotating ring magnetic having a plurality of North-South pole pairs each having a unique period length. The processing circuitry includes a first bridge formed from the first and second pairs of magnetic-field sensing elements and a second bridge formed from the third and fourth pairs of magnetic-field sensing elements. The angle includes a value from 0° to 360°. The first, second, third and fourth pairs of magnetic-field sensing elements are each disposed on a first axis. The first, second, third and fourth pairs of magnetic-field sensing elements each have a sensitivity in a first direction along the first axis. The angle sensor is formed on a single die.

The present invention relates to a hall electromotive force signal detection circuit and a current sensor thereof each of which is able to achieve excellent wide-band characteristics and fast response as well as high accuracy. A difference calculation circuit samples a component synchronous with a chopper clock generated by a chopper clock generation circuit, out of an output voltage signal of a signal amplifier circuit, at a timing obtained from the chopper clock, so as to detect the component. An integrating circuit integrates an output from the difference calculation circuit in the time domain. An output voltage signal from the integrating circuit is fed back to a signal amplifier circuit via a third transconductance element.

Disclosed are methods and devices for detecting retained surgical items or other objects having a magnetic signature within a corpus of a patient. The device can comprise a handle, a shaft extending from the handle, and a distal sensing portion positioned distally of the shaft. The distal sensing portion can comprise one or more gradiometers comprising a plurality of magnetometers. The device can further comprise one or more output components configured to generate a user output to alert a user of a detected object.

The present disclosure relates to chopper amplifier circuits with inherent chopper ripple suppression. Example implementations can realize a doubly utilized chopper amplifier circuit that is a current-saving circuit with a wake-up function that is capable of providing a self-wake signal in order to change into a fast, low-jitter/low-latency mode, and to provide a wake-up signal for a sleeping microprocessor or a system in response to signal changes.

Methods and apparatus for reducing noise in RF signal chain circuitry for a low-field magnetic resonance imaging system are provided. A switching circuit in the RF signal chain circuitry may include at least one field effect transistor (FET) configured to operate as an RF switch at an operating frequency of less than 10 MHz. A decoupling circuit may include tuning circuitry coupled across inputs of an amplifier and active feedback circuitry coupled between an output of the amplifier and an input of the amplifier, wherein the active feedback circuitry includes a feedback capacitor configured to reduce a quality factor of an RF coil coupled to the amplifier.

In one aspect, a magnetic-field sensor includes main coil circuitry configured to generate a first magnetic field signal at a first frequency. A reflected signal is generated from a target caused by the first signal generated by the main coil circuitry. The magnetic field sensor also includes magnetoresistance circuitry configured to receive an error signal. The error signal is formed from a combination of the reflected signal and a second magnetic field signal. The magnetic-field sensor further includes analog circuitry configured to receive an output signal from the magnetoresistance circuitry, digital circuitry configured to receive an output signal from the analog circuitry, a mixer configured to receive a feedback signal from one of the digital circuitry or the analog circuitry, and secondary coil circuitry configured to receive a driver signal from the mixer causing the secondary coil circuitry to generate the second magnetic field signal at the first frequency.

A magnetic sensor may include a comparator to receive a first signal indicating a strength of a magnetic field sensed by a first sensing component of the magnetic sensor, receive a second signal indicating a strength of a magnetic field sensed by a second sensing component of the magnetic sensor, perform an error check associated with the first sensing component and the second sensing component, the error check being performed based on the first signal and the second signal, and provide an indication of a result of the error check. The magnetic sensor may include a protocol encoder to receive the first signal, receive the indication of the result of the error check, and provide an output that includes the indication of the result of the error check.