A magnetic field generator includes a plurality of conductive windings comprising a first conductive winding arranged in a first plane and a second conductive winding arranged in a second plane that is substantially parallel to the first plane. The plurality of conductive windings are configured to generate, when supplied with a drive current, a first component of a compensation magnetic field. The first component of the compensation magnetic field is configured to actively shield a magnetic field sensing region located between the first conductive winding and the second conductive winding from ambient background magnetic fields along a first axis that is substantially orthogonal to the first plane and the second plane.

A magnetic field generator includes a first planar substrate, a second planar substrate positioned opposite to the first planar substrate and separated from the first planar substrate by a gap, a first wiring set on the first planar substrate, a second wiring set on the second planar substrate, and one or more interconnects between the first planar substrate and the second planar substrate. The one or more interconnects electrically connect the first wiring set with the second wiring set to form a continuous electrical path. The continuous electrical path forms a conductive winding configured to generate, when supplied with a drive current, a first component of a compensation magnetic field configured to actively shield a magnetic field sensing region located in the gap from ambient background magnetic fields along a first axis that is substantially parallel to the first planar substrate and the second planar substrate.

Methods and apparatus for a sensor system having a first magnetic field sensing element with first and second segments where the first and second segments are located at positions to generate magnetic field bias in opposite directions for reducing sensitivity due to misalignment of the first and second segments. A processing module is configured to receive an output of the magnetic field sensing element.

Methods and apparatus for a sensor system having a first magnetic field sensing element with first and second segments where the first and second segments are located at positions to generate magnetic field bias in opposite directions for reducing sensitivity due to misalignment of the first and second segments. A processing module is configured to receive an output of the magnetic field sensing element.

A wiring assembly includes a differential input port, a differential output port, and first and second pairs of electrical leads. The differential input port is configured to receive a differential signal from a sensor at a first end of the wiring assembly. The differential output port is configured to output the differential signal at a second end of the wiring assembly. The first and second pairs of electrical leads convey the differential signal from the first end to the second end, and are connected to one another at the first end and at the second end in a configuration that cancels pickup of an ambient magnetic field by the wiring assembly.

A magnetic field sensor can include a magnetic field sensor can include a substrate having a major surface in an x-y plane with an x axis and a y axis. The magnetic field sensor can also have an external field sensing circuit disposed upon the substrate and responsive to an external magnetic field generated outside of the magnetic field sensor. The external field sensing circuit can include one or more magnetoresistance elements, each having a respective reference layer with a magnetic direction parallel to the y axis and in the x-y plane. The one or more magnetoresistance elements can be operable to generate a magnetoresistance element signal responsive to the external magnetic field. The external field sensing circuit can also include a component determination module coupled to receive the magnetoresistance element signal and operable to generate a measured x-dominant value and a measured y-dominant value, wherein the measured x-dominant value is indicative of an x component and a y component of the external magnetic field projected onto the x-y plane, wherein the measured x-dominant value more indicative of the x component and less indicative of the y component, wherein the measured y-dominant value is indicative of the x component and the y component, wherein the measured y-dominant value is more indicative of the y component and less indicative of the x component.

A magnetic field sensor can include a magnetic field sensor can include a substrate having a major surface in an x-y plane with an x axis and a y axis. The magnetic field sensor can also have an external field sensing circuit disposed upon the substrate and responsive to an external magnetic field generated outside of the magnetic field sensor. The external field sensing circuit can include one or more magnetoresistance elements, each having a respective reference layer with a magnetic direction parallel to the y axis and in the x-y plane. The one or more magnetoresistance elements can be operable to generate a magnetoresistance element signal responsive to the external magnetic field. The external field sensing circuit can also include a component determination module coupled to receive the magnetoresistance element signal and operable to generate a measured x-dominant value and a measured y-dominant value, wherein the measured x-dominant value is indicative of an x component and a y component of the external magnetic field projected onto the x-y plane, wherein the measured x-dominant value more indicative of the x component and less indicative of the y component, wherein the measured y-dominant value is indicative of the x component and the y component, wherein the measured y-dominant value is more indicative of the y component and less indicative of the x component.

One embodiment is a magnetic field measurement system that includes at least one magnetometer having a vapor cell, a light source to direct light through the vapor cell, and a detector to receive light directed through the vapor cell; at least one magnetic field generator disposed adjacent the vapor cell; and a feedback circuit coupled to the at least one magnetic field generator and the detector of the at least one magnetometer. The feedback circuit includes at least one feedback loop that includes a first low pass filter with a first cutoff frequency. The feedback circuit is configured to compensate for magnetic field variations having a frequency lower than the first cutoff frequency. The first low pass filter rejects magnetic field variations having a frequency higher than the first cutoff frequency and provides the rejected magnetic field variations for measurement as an output of the feedback circuit.

An object of the present invention is to provide a magnetic sensor that can reduce influences of a disturbance magnetic field while ensuring high detection sensitivity. The magnetic sensor includes a sensor chip 20 having an element formation surface 20S on which magnetic detection elements MR3, MR4 are formed, a first magnetic member 31 placed on the element formation surface 20S and having a first height H1 as a height from the element formation surface 20S, and a second magnetic member 32 located on an opposite side of the magnetic detection elements MR3, MR4 to the first magnetic member 31 and having a second height H2 lower than the first height H1. According to the present invention, because the height H2 of the second magnetic member 32 is lower than that of the first magnetic member 31, a detection magnetic field attracted to the second magnetic member 32 can be reduced while a disturbance magnetic field is shielded by the second magnetic member 32. Accordingly, influences of the disturbance magnetic field can be reduced while high detection sensitivity is ensured.

An object of the present invention is to provide a magnetic sensor that can reduce influences of a disturbance magnetic field while ensuring high detection sensitivity. The magnetic sensor includes a sensor chip 20 having an element formation surface 20S on which magnetic detection elements MR3, MR4 are formed, a first magnetic member 31 placed on the element formation surface 20S and having a first height H1 as a height from the element formation surface 20S, and a second magnetic member 32 located on an opposite side of the magnetic detection elements MR3, MR4 to the first magnetic member 31 and having a second height H2 lower than the first height H1. According to the present invention, because the height H2 of the second magnetic member 32 is lower than that of the first magnetic member 31, a detection magnetic field attracted to the second magnetic member 32 can be reduced while a disturbance magnetic field is shielded by the second magnetic member 32. Accordingly, influences of the disturbance magnetic field can be reduced while high detection sensitivity is ensured.