Abstract: This method for detecting a disturber of magnetic field amplitude comprises: the emitting (62) of several magnetic fields of different frequencies from a same uniaxial magnetic field source, the amplitudes of the magnetic field emitted at two different unspecified frequencies being related to each other by a predetermined ratio, the measurement (64) of the amplitude of these magnetic fields at different frequencies by means of a same sensor, and the reporting (70) of an amplitude disturber if a ratio between two of said measured amplitudes diverges from a predetermined threshold of the predetermined ratio which relates the amplitudes of the magnetic fields emitted at the same frequencies and, if not, the absence of any reporting.

Abstract: A magnetic-field sensor adapted to detect an external magnetic field. The magnetic-field sensor including a first chip, having a first magnetoresistive structure for detection of the external magnetic field, the first magnetoresistive detection structure including an electrical-contact pad and magnetoresistive element, and a second chip housing an integrated electronic circuit and a magnetic-field generator. The first and second chips being mutually arranged in such a way that the integrated electronic circuit can be electrically coupled to the electrical-contact pad of the magnetoresistive structure and in such a way that the magnetic-field generator can be magnetically coupled to the magnetoresistive structure.

Abstract: A door, or window detector incorporates a magnet and a magnetometer. Dual loop processing can be provided for real-time signals from the magnetometer, as the magnet moves relative to it, to determine when at least one of small gap or large gap indicating alarms should be issued. Security can be substantially increased by randomizing the orientation of the magnet.

Abstract: Systems and methods for detecting electromagnetic waves are disclosed. A system for use in detecting an electromagnetic wave includes an inductive device and a spintronic device. The inductive device generates an induced electromagnetic field when the inductive device receives the electromagnetic wave. The spintronic device has an impedance that changes when exposed to the induced electromagnetic field from the inductive device. The change in impedance is indicative of the electromagnetic wave received by the inductive device. Another system for use in detecting or transmitting an electromagnetic wave includes a conductive device and an inductive device. The inductive device is configured to generate an induced electromagnetic wave when the inductive device receives an electromagnetic wave passed by the conductive device. Another system for detecting electromagnetic wave permittivity or permeability of an object includes a pair of antennas and an inductive device.

Abstract: The disclosure relates to a magnetometer in which direction of the Earth's magnetic field is determined on the basis of time variant differences in the inductance of a sensor coil of the digital compass which is a function of the orientation of the sensor coil with respect to the Earth's magnetic field. The magnetometer includes a sensing coil, a feedback resistor, and a comparator.

Abstract: A method of authentication of a terminal generating a magnetic field by a transponder including an oscillating circuit from which a D.C. voltage is generated, wherein at least one quantity depending on the coupling between the transponder and the terminal is compared with at least one reference value.

Abstract: An active device is provided that is energized by an optical source and uses an active paramagnetic medium to transfer this energy to a resonant circuit enabling new classes of electronic components.

Abstract: A magnetic force microscope capable of measuring the absolute value of a magnetic field with high resolution without causing a change in magnetization state of the probe. The magnetic force microscope includes a cantilever, a probe, a displacement detector that detects a displacement of the probe, a specimen carrier, and various transfer units. The magnetic force microscope that measures an undulation distribution as well as a magnetic field distribution on the surface of a specimen placed on the specimen carrier is further provided with a magnetic-field impress-unit that impresses a magnetic field to the probe, and an output of the magnetic-field impress-unit is controlled such that a magnetic force impressed onto the probe 5 is turned zero to thereby measure a magnetic field distribution on the surface of the specimen.

Abstract: A printed circuit in which, in going from one end to another, a same conductive line is wound successively: around the first winding axis to form at least one half-turn of a first coil, then around the second winding axis to form at least one half-turn of a second coil, then around the first winding axis to form at least one half-turn of a first coil, then around the second winding axis to form at least one half-turn of a second coil.

Abstract: A system and method for measuring a magnetocardiogram (MCG) in order to measure a weak magnetic field generated from the heart of a small animal such as a laboratory rat are provided. The system includes a case, a SQUID sensor located and fixed inside the case to detect magnetism, a platform arranged near the SQUID sensor inside the case, the small animal being placed on the platform, a linear station to which the platform is fixed to move a location of the platform, and a control unit configured to control operations of the SQUID sensor and the linear station and measure the MCG of the small animal using intensities of the magnetism detected by the SQUID sensor.

Abstract: A meter reader for reading a meter have a display portion displaying a total output of a quantity being metered and plural incremental outputs defining the total output. The meter reader includes a sensing mechanism for sensing one of the plural incremental outputs in the meter display portion, and a processing unit coupled to the sensing mechanism for accumulating incremental outputs sensed by the sensing mechanism and for determining accumulated meter output over a time period based on the accumulated incremental outputs. Also included is an output mechanism for outputting the accumulated meter output determined by the processing unit. In one example, the sensing mechanism includes a sensor for sensing only a least significant incremental output in usage included in the meter display portion, and an emitter for illuminating the least significant incremental output included in the meter display portion.

Abstract: One exemplary embodiment includes a method including providing a battery, producing a first magnetic field so that a second magnetic field is induced in the battery, sensing a magnetic field resulting from the interaction of the first magnetic field and the second magnetic field, utilizing the sensed net magnetic field to determine the state of charge of the battery.

Abstract: Disclosed are a medium discrimination apparatus and a discrimination method thereof. The medium discrimination apparatus comprises first and second magnetic sensor, a differential analog/digital converter and a controller. The first magnetic sensor senses a magnetic component printed at a specific position of an introduced medium and having a form of an analog signal containing a first noise generated from an internal circuit and a second noise generated from an operation of an actuator. The second magnetic sensor senses the first and second noises which are caused when the medium is transferred and has a form of an analog signal. The differential analog/digital converter performs a subtraction operation for the first and second noises sensed by the first and second magnetic sensors and convert result signals into one digital signal. The controller determines if the introduced medium is genuine or counterfeit according to the digital signal.

Abstract: A magnetic sensor inspection apparatus has a rectangular frame including a stage, a probe card, and a plurality of magnetic field generating coils. A wafer-like array of magnetic sensors is mounted on the stage, which is movable in horizontal and vertical directions. The probe card includes a plurality of probes which are brought into contact with a plurality of magnetic sensors encompassed in a measurement area. The magnetic field generating coils are driven to generate a magnetic field toward the stage. A plurality of magnetic field environment measuring sensors is arranged in the peripheral portion of the probe card surrounding the probes. A magnetic field controller controls magnetic fields generated by the magnetic field generating coils based on the measurement result of the magnetic field environment measuring sensors. Thus, it is possible to concurrently inspect a wafer-like array of magnetic sensors with the probe card.

Abstract: A method to measure a magnetic field is provided. The method includes applying an alternating drive current to a drive strap overlaying a magnetoresistive sensor to shift an operating point of the magnetoresistive sensor to a low noise region. An alternating magnetic drive field is generated in the magnetoresistive sensor by the alternating drive current. When the magnetic field to be measured is superimposed on the alternating magnetic drive field in the magnetoresistive sensor, the method further comprises extracting a second harmonic component of an output of the magnetoresistive sensor. The magnetic field to be measured is proportional to a signed amplitude of the extracted second harmonic component.

Abstract: Magnetic field sensing method and apparatus of this disclosure uses two tunneling magneto-resistor (TMR) devices. Angles of the free magnetizations of the two TMR devices with respect to a fixed direction are set in a first to fourth period. In the first to fourth period, the two TMR devices act as a TMR sensing unit and a zero-field reference unit by turns, and each of the conductance difference between the sensing unit and the zero field reference unit is also obtained in each of the first to fourth period. Finally, the four conductance differences are summed up.

Abstract: Provided are an inspection device and an inspection method capable of achieving improved magnetic field sensitivity by using a magnetic thin film of a small film thickness. A light-emitting unit 1 emits light of a first wavelength for acquiring magnetic field inspection information and a second wavelength for acquiring inspection object surface information. A selection unit 6 selects information from an inspection object 4 and information from a magnetophotonic crystal film 3 acquired by light irradiation performed by an irradiation unit 2. An image generation unit 9 generates image data based on the magnetic field inspection information acquired with the first wavelength and the inspection object surface information acquired with the second wavelength selected by the selection unit. Each of the generated image data is displayed on a display unit 10.

Abstract: Provided is a coercive-force specifying apparatus capable of creating a demagnetization curve for each divisional area of a coercive-force distributed magnet without breaking the coercive-force distributed magnet and of specifying an average coercive force for each divisional area precisely. A coercive force specifying apparatus of the present invention includes: a yoke including an insertion space into which a coercive-force distributed magnet is to be inserted; a magnetizing coil; a search coil that detects a magnetization change when the magnetic field is applied to the coercive-force distributed magnet; and a tracer that creates a demagnetization curve on a basis of a voltage value generated due to the magnetization change. The end face is provided with two or more loop-shaped thread grooves bored therein, the search coil being provided in each thread groove.

Abstract: Cyclic motion of a ferromagnetic part in an environment made noisy by at least one electric source with an A.C. component is measured using at least one first magnetometer sensitive to the moving part and a sensor of an image of current in the electric source. An estimate is calculated of noise linked to the electric source on a signal measured by the first magnetometer and then subtracted from the measured signal.

Abstract: An embodiment of a magnetic-field sensor includes a magnetic-field sensor arrangement and a magnetic body which has, for example, a non-convex cross-sectional area with regard to a cross-sectional plane running through the magnetic body, the magnetic body having an inhomogeneous magnetization.

Abstract: An apparatus for determining an integral strength of a magnet, including a magnetically attractive specimen, a force-sensing device for receiving the specimen and determining a magnitude of a first force applied by the specimen against the force-sensing device in the presence of the magnet and a magnitude of a second force applied by the specimen against the force-sensing device in the absence of the magnet, and a platform for receiving the magnet and for positioning the magnet at a desired distance above the specimen.

Abstract: A device for recognizing when an object or a person crosses a threshold that is marked by a magnetic field comprises a first magnetic field sensor that is designed to detect a first magnetic field component of the magnetic alternating field and to deliver an associated magnetic field sensor signal. The device comprises a second magnetic field sensor that is designed to detect a second magnetic field component of the alternating magnetic field. The device also comprises an evaluator that is designed to deliver information in response to a change in a phase relationship between the magnetic field sensor signal delivered by the first magnetic field sensor and a reference signal based on the detection of the second magnetic field component by the second magnetic field sensor, said information indicating that the object or person has crossed the marked threshold.

Abstract: A magnetic field measuring device includes a support base, a measuring mechanism, and a displacement sensor. The measuring mechanism is positioned on the support base, and includes a mounting plate, a swing arm, a connecting member, an elastic member, and a measuring magnet. The mounting plate is connected to the support base. The swing arm is rotatably positioned on the mounting plate. The elastic member is positioned between the connecting member and the swing arm. The measuring magnet is connected to the swing arm, opposite to the support base. The displacement sensor is positioned on the support base, opposite to the swing arm.

Abstract: A magnetic field verifier apparatus includes a magnetic field detection element configured to produce a voltage signal in response to an applied magnetic field wherein the voltage signal corresponds to the strength of the applied magnetic field. Substantially identical circuit boards or units are connected to a central unit or mother board to place magnetic field detection elements of each board or unit in an mutually approximately orthogonal relationship. A microcontroller is in communication with the voltage signal. The magnetic field verifier apparatus is configurable to sense particular field strengths at various frequencies and store the readings to provide the user with a reliable verification that a particular magnetic field strength has been produced in a particular environment.

Abstract: A magnetic field sensor includes a diagnostic circuit that allows a self-test of most of, or all of, the circuitry of the magnetic field sensor, including a self-test of a magnetic field sensing element used within the magnetic field sensor. The magnetic field sensor can generate a diagnostic magnetic field to which the magnetic field sensor is responsive.

Abstract: Described herein are embodiments of methods, devices and computer program products for tamper detection in a meter. One aspect of the method includes using a magnetic field strength sensor to continuously detect magnetic field strength proximate to a meter. In one aspect, the magnetic field strength sensor produces an analog voltage signal proportional to the detected magnetic field strength. The analog voltage signal of the sensor is continuously converted to a digital voltage signal. The digital voltage signal is stored in a memory at timed intervals, and the digital voltage signal is monitored for an aberration that indicates tampering of the meter. If tampering is detected, then an alarm is triggered to indicate the tampering.

Abstract: The invention is a method, described with the appropriate auxiliary electronic circuitry, for compensating the effect of the earth's magnetic field on Giant Magneto-Impedance magnetic sensors. The method as taught is an alternate way of cancelling out the effect of the very large residual earth's magnetic field using an impedance-tuning circuit (i.e. electrical compensation) rather than the usual magnetic type of compensation.

Abstract: A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an S/N ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.

Abstract: Magnetic field current sensing devices, systems and methods are disclosed. In an embodiment, a current sensor includes a semiconductor die; an isolation layer disposed on the semiconductor die; at least one anchor pad disposed on the isolation layer; a current input and a current output galvanically isolated from the semiconductor die; at least one bond wire coupled to the current input and the current output, a longitudinal portion of the at least one bond wire disposed between the current input and the current output being stitched to the at least one anchor pad; and at least one sensor element arranged to sense a magnetic field induced by a current flowing in the at least one bond wire.

Abstract: A magnetic field sensor includes a reference-field-sensing circuit channel that allows a calibration or a self-test of the circuitry of the magnetic field sensor. The magnetic field sensor can generate a reference magnetic field to which the magnetic field sensor is responsive.

Abstract: A sheet identifying apparatus includes: an excitation coil disposed upstream in a passage through which a sheet inserted into an input port passes and wound on an outer periphery of the passage; a first output unit that detects a magnetization variation of a magnetic element due to the excited excitation coil when the sheet having the magnetic element passes through a region of the passage where the excitation coil is disposed in a state where an AC current is applied to the excitation coil and that outputs a first detection signal when the magnetization variation is detected; and a second output unit that detects that the sheet passes through a region downstream in the passage on the basis of a characteristic of the sheet without using the magnetic element and that outputs a second detection signal when detecting that the sheet passes through the region.

Abstract: A waterproof housing that encloses a hand-held magnetometer for underwater use and includes a first portion open at one end and connected to a second portion with one end open and accessible through the first portion and terminating at a closed end. The magnetometer has first and second housings and is inserted into the first portion open end so that the second housing is received into the second portion and the first housing is received into the first portion. A base seal is inserted into the first portion open end to provide a fully functional magnetometer protected from water incursion at depth.

Abstract: A magnetic field vector sensor includes a substrate parallel to a plane, a support mobile relative to it and rotatable about a vertical rotation axis perpendicular to it, a magnetic field source generating a field having a moment in a non-perpendicular direction, the source being fixed to the support with no degree-of-freedom to exert torque on the support when a field to be measured is present, the field being non-collinear with the moment, a transducer to convert torque exerted on the support into a field amplitude of a component of the field along a measurement axis in the plane, wherein the source comprises a magnetostrictive permanent magnet for generating the field having a moment whose direction varies with stress on the magnet, and wherein the sensor further comprises a controllable device to reversibly modify the moment direction, and a stress generator to vary stress and hence moment direction.

Abstract: This disclosure provides systems, methods and apparatus for detecting foreign objects. In one aspect an apparatus for detecting a presence of an object is provided. The apparatus includes a resonant circuit having a resonant frequency. The resonant circuit includes a sense circuit including an electrically conductive structure. The apparatus further includes a coupling circuit coupled to the sense circuit. The apparatus further includes a detection circuit coupled to the sense circuit via the coupling circuit. The detection circuit is configured to detect the presence of the object in response to detecting a difference between a measured characteristic that depends on a frequency at which the resonant circuit is resonating and a corresponding characteristic that depends on the resonant frequency of the resonant circuit. The coupling circuit is configured to reduce a variation of the resonant frequency by the detection circuit in the absence of the object.

Abstract: A magnetic field sensor device 1 includes a sensor section 100 that includes a magneto-impedance device 110 having a magnetic amorphous structure, and rod-shaped core sections 130 and 131 that guide a magnetic field to the magnetic amorphous structure in a longitudinal direction with respect to the magnetic amorphous structure. The core sections 130 and 131 may be provided on either side of the magnetic amorphous structure in the longitudinal direction. The core sections 130 and 131 may be disposed so that the longitudinal direction of the magnetic amorphous structure coincides with the longitudinal direction of the core sections 130 and 131. The magnetic field sensor device 1 may include environmental magnetic field cancellation means 140 and 141 that generate a correction magnetic field that cancels the environmental magnetic field input to the magnetic amorphous structure.

Abstract: A method for operating a metal detection system that comprises a balanced coil system. One embodiment of the method comprises: determining the phase and magnitude of related signals at least for a first metal contaminant for at least two transmitter frequencies and for at least two particle sizes of the first metal contaminant; determining the phase and magnitude of the related signal for a specific product for the at least two transmitter frequencies; comparing information established at least for the first metal contaminant and the information established for the product; determining a transmitter frequency with which signal components of smallest sized particles of the at least first metal contaminant differ sufficiently or most in phase and amplitude from the phase and amplitude of the product signal; and selecting the transmitter frequency for measuring the product. A metal detection apparatus adapted to operate according to an exemplary method is also provided.

Abstract: A planar magnetic field probe is provided. The planar magnetic field probe increases the sensitivity of magnetic field intensity detection by using a left multi-sensor loop and a right multi-sensor loop formed by a first patterned metal layer and a second patterned metal layer, and decreases the electric field noise coupling by surrounding the left multi-sensor loop and the right multi-sensor loop with a symmetrical shielding metal structure formed by a first patterned shielding metal layer, a second patterned shielding metal layer and a plurality of through vias.

Abstract: An apparatus for monitoring the movement of a piston disposed within a housing comprises a pin which is responsive to the axial movements of a piston in the housing, the pin having an end which is magnetically coupled to a first ring magnet slidably disposed on a magnet carrier of an indicator body, a second ring magnet disposed on the magnet carrier having its poles oriented so as to repel the first ring magnet, and a retainer for holding the first and second ring magnets on the magnet carrier is described. Additionally, a method for operating the cycle indicator apparatus is also provided. The housing is comprised of one or a plurality of ports through which lubricants are delivered to one or a plurality of corresponding points within a machine.

Abstract: A length measurement apparatus (10) has a bistable magnetic element (102), an elongated physical scale (200) with a plurality of measurement graduation elements (202) spaced apart from one another and a reading head (100) movable relative to the physical scale (200) in its longitudinal extent and which includes a first and second reading head magnet (114a b) arranged transverse to the longitudinal extent and with opposite polarity to one another. The measurement graduation elements (202) each have a magnetic short-circuit element (202) to suppress the magnetic field (116a) of the first reading head magnet (114a) in a first relative position of the reading head (100) and the magnetic field (116b) of the second reading head magnet (114b) in a second relative position of the reading head (100).

Abstract: Disclosed is a current sensor including magnetic sensors disposed on a conductor having at least two separated current-carrying areas with different current magnitudes and detecting a magnetic field generated according to currents flowing through the conductor and a controller controlling outputs of the magnetic sensors, wherein the magnetic sensors are disposed in at least two respective areas having different current magnitudes and the controller switches outputs of the magnetic sensors.

Abstract: A sensor with multiple magnetic field sensing elements for use in current sensing and other applications is presented. In one configuration, the sensor can obtain differential and absolute current measurements of current in current-carrying conductors. When employed in a ground fault interrupter (GFI) application, a first magnetic field sensing element can be used to measure the absolute current flowing in the phase conductor (phase current), a second magnetic field sensing element can be used to measure the absolute current flowing in the neutral conductor (neutral current) and a difference between the phase and neutral currents can be measured by a third magnetic field sensing element or determined from measurements of the first and second magnetic field sensing elements. In another configuration, the sensor can obtain a measure of the difference between currents and/or the sum of currents in current-carrying conductors.

Abstract: There is provided a coercivity performance determination device for a coercivity distribution magnet that is capable of determining, in a short period of time, with precision, and at as low a testing cost as possible, whether or not each part of one coercivity distribution magnet has a coercivity that is equal to or greater than the required coercivity. A coercivity determining device of the present invention comprises: a substantially C-shaped magnetic body; excitation means that generates a magnetic flow in the magnetic body; and a flux meter that measures the residual magnetic flux of the coercivity distribution magnet. Protrusions are provided at corresponding positions on two opposing end faces of the magnetic body, and the coercivity distribution magnet is held between the two protrusions to form an annular magnetic circuit. An external magnetic field generation means is formed by magnetic regions caused by the protrusions and non-magnetic regions comprising the air in the periphery thereof.

Abstract: A magnetic field sensor includes a lead frame having a plurality of leads, at least two of which have a connection portion and a die attach portion. A semiconductor die is attached to the die attach portion of the at least two leads. In some embodiments, at least one passive component is attached to the die attach portion of at least two leads.

Abstract: A magnetic field sensor includes a diagnostic circuit that allows a self-test of most of or all of, the circuitry of the magnetic field sensor, including a self-test of a magnetic field sensing element used within the magnetic field sensor. The magnetic field sensor can generate a diagnostic magnetic field to which the magnetic field sensor is responsive.

Abstract: A sensor system comprises a sensor element adapted to sense at least one physical quantity, wherein the sensor element is adapted to generate a sensor signal in response to the at least one physical quantity, an evaluation circuit adapted to detect a manipulation of the sensor system based on the sensor signal and stored reference values and to output an indication signal in response to a detected manipulation and a package, the package housing at least the sensor element and the evaluation circuit.

Abstract: A semiconductor process integrates three bridge circuits, each include magnetoresistive sensors coupled as a Wheatstone bridge on a single chip to sense a magnetic field in three orthogonal directions. The process includes various deposition and etch steps forming the magnetoresistive sensors and a plurality of flux guides on one of the three bridge circuits for transferring a “Z” axis magnetic field onto sensors orientated in the XY plane.

Abstract: A process for measuring the gradient or an n-th order derivative, in which n is greater than 1, in a direction z, of a component Hx of a magnetic field, the component being invariant, at least locally, in a direction y. The method includes: a) positioning of N (N>n+1) elementary field sensors, each sensor being offset, relative to the neighboring sensors, along y by a distance Ty and along the z axis by a distance ?z, b) measurement of the field by each of the N sensors, and c) calculation of the desired gradient, or the desired nth-order derivative, as a function of the measurements of the field obtained during b).

Abstract: According to the present invention, a method for determining coercivity of a coercivity distribution magnet, whereby coercivity of each portion in the coercivity distribution magnet can be determined with good accuracy without, for example, cutting the coercivity distribution magnet into pieces and thus quality assurance can be achieved with good accuracy, is provided.

Abstract: A real time Schumann frequency (approximately 6-10 Hz) band-based, lightning strike detector system is described, comprising: first and second sensor systems, each sensor system comprising: first and second magnetic field sensors, each sensor having a preferential directional sensitivity, wherein the sensors are arranged with their preferential directional sensitivity substantially orthogonal to each other; signal lines coupled to the sensors; an amplifier to coupled to the signal lines; an output of the amplifier coupled to a processor; and power source coupled to the amplifier and processor, wherein the first and second sensor systems are separated from each other by at least 400 miles, and wherein each sensor system upon detection of a Schumann frequency from a lightning strike provides a respective orientation angle, wherein an intersection of the angles of orientation following a great circle path indicates a location of the lightning strike.

Abstract: The invention is to provide a magnetic sensor capable of detecting magnetic particles over a wide range of number and of suppressing an increase in a detection area. The magnetic sensor includes a detection part, a selecting device connected electrically to an end of the detecting part, and a sensing amplifier for receiving a signal from the detecting part, wherein the detecting part includes at least two magnetoresistive films serially connected.