366results about "Magnetic field offset compensation" patented technology

The invention discloses a Hall sensor combination system and method for magnetic imaging stability optimization. The system comprises a three-dimensional orthogonal Hall sensor array; the embedded encoder module is used for converting the analog magnetic field signals acquired by the sensor array into digital encoding signals with timestamps; the control module constructs an electromagnetic feature extraction model and is used for carrying out time-frequency domain conjoint analysis on the digital coding signals to obtain magnetic environment disturbance feature parameters; generating a compensation magnetic field parameter opposite to the magnetic environment disturbance characteristic parameter by adopting a closed-loop feedback mechanism; establishing a real-time data channel with a preset electromagnetic imaging module and a preset magnetic field generation module through a preset communication protocol; and constructing a magnetic environment state space model corresponding to the three-dimensional orthogonal Hall sensor array, and obtaining magnetic field distribution data to dynamically adjust and compensate magnetic field parameters so as to realize active magnetic interference cancellation in a three-dimensional space. Problems in the prior art can be effectively solved, and the precision and stability of magnetic imaging are improved.

The invention belongs to the technical field of magnetic particle imaging, particularly relates to a magnetic particle imaging system and method based on a flexible receiving coil array, and aims to solve the problems that an existing rigid receiving coil is poor in biological surface adaptability and low in signal-to-noise ratio for micro geometric texture imaging. According to the structure, a receiving coil array adheres to the surface of an object to be measured, the receiving coil array and a compensation coil array are distributed on the two sides of a flexible substrate, the receiving coil array is used for receiving magnetic nanoparticle signals, and the partitioned small compensation coil array is used for conducting feed-through interference and electromagnetic interference compensation on a receiving coil; the reconstruction method comprises the following steps: sequentially carrying out Fourier transform on the collected receiving signals, extracting in-phase third harmonics and superposing to obtain processed signals, interpolating to construct a sinogram for Cartesian coordinate distribution, and reconstructing the three-dimensional particle concentration distribution of a measured object by a filtering back projection method. A flexible receiving coil array strategy is adopted, an adaptive reconstruction method is provided, and the imaging signal-to-noise ratio is improved.

A calibration method of the magnetic field model and a controller for electromagnetic positioning are provided. In the method, a magnetic field is established through a magnetic field transmitter; measurement data is obtained through a magnetic field sensor, where the measurement data includes the amplitude of induced voltage at multiple measurement positions in the magnetic field; and the magnetic field model is corrected according to the error between the measurement data and simulated data correction, where the magnetic field model is used to generate simulation data corresponding to multiple measurement locations. The steps of modifying the magnetic field model include: establishing one or more objective functions through the nonlinear least squares method based on the error between the measured data and the simulated data; and determining the modified magnetic field model based on one or more solutions of the objective function. Therefore, positioning accuracy can be improved.

The invention discloses an electromagnetic interference suppression method and system for ultra-low field magnetic resonance imaging, and belongs to the technical field of nuclear magnetic resonance, and the system comprises an electromagnetic interference signal collection module which is composed of a plurality of EMI coils and corresponding signal collectors and actively detects EMI signals from the environment; the electromagnetic interference suppression module is used for performing model training by using the data, performing electromagnetic interference suppression through a model, predicting and eliminating an EMI component based on the electromagnetic interference suppression model, and outputting k space data without EMI; and the image reconstruction module is used for receiving the EMI-free k-space data and carrying out averaging and image reconstruction on the data so as to generate a high-quality MRI image. According to the invention, EMI noise is effectively suppressed, image quality is improved, and mobile and portable development of MRI equipment is promoted.

The invention is applicable to the technical field of magnetic field measurement, and provides a current sensor magnetic field measurement method based on a tunneling magnetoresistance effect, which comprises the following steps of: analyzing a real-time output signal through a machine learning algorithm based on a mapping relation model of a parasitic capacitance parameter and a signal characteristic of a tunneling magnetoresistance sensor circuit; determining an actual value of a parasitic capacitance parameter; controlling a negative capacitance generation circuit and a numerical control resistance network to adjust an equivalent negative capacitance value and a resistance value according to the actual value of the parasitic capacitance parameter, and generating a matched compensation parameter set; feature extraction is carried out on the compensated signal, and an effective magnetic field component is obtained through multi-resolution time domain decomposition and phase consistency detection; calculating the magnetic field intensity and the change gradient based on the effective magnetic field component, and determining the effective working frequency range of the sensor according to the signal attenuation characteristic; and dynamically adjusting a compensation strategy according to a comparison result of the effective working frequency range and a preset target frequency band, and reducing measurement errors.

A method for making axial magnetic field measurements in a downhole tool includes evaluating axial magnetic field measurements to determine a magnetic interference offset and removing the magnetic interference offset to obtain compensated axial magnetic field measurements.

To provide a magnetic sensor device in which influence of stress applied is suppressed.SOLUTION: A magnetic sensor device 1 comprises magnetic sensors 10, 20, 30, and a support medium 4. The center of mass of an element arrangement area of the magnetic sensors 10, 20, 30 is displaced from center of mass C4 of a reference plane 4a of the support medium 4. Each of the magnetic sensors 10, 20, 30 includes four resistance parts composed of a plurality of MR elements. Magnetization of a free layer 54 in two resistance parts contains a component in a third magnetization direction. Magnetization of the free layer 54 in each of the remaining two resistance parts contains a component in a fourth magnetization direction opposite to the third magnetization direction.SELECTED DRAWING: Figure 8

A calibration system leverages a 3-axis Helmholtz coil device for generating a referential magnetic field for calibrating the magnetometer on-board a vehicle. The calibration system may include the magnetic field generator, a vehicle platform, and a computing device to determine the calibration parameters. The vehicle platform supports the vehicle with the magnetometer being calibrated. The magnetic field generator generates a referential magnetic field in three-dimensional space for calibration of the magnetometer. The computing device is configured to: receive magnetometer measurements from the magnetometer on-board the vehicle during generation of the referential magnetic field, and determine calibration parameters for calibrating the magnetometer based on the magnetometer measurements and the referential magnetic field generated by the magnetic field generator.

A method for extracting information about one or more magnetic sources includes obtaining a first plurality of signals corresponding to magnetic sensor data generated by one or more magnetometers in an unshielded environment at a first time; receiving second information of a direction and a magnitude of a first known magnetic field applied to the one or more magnetometer, the first plurality of signals is acquired while the first known magnetic field is applied and wherein the first known magnetic field encodes directional information of the one or more magnetic sources into the first plurality of signals; extracting the information comprising three-dimensional spatial information of the one or more magnetic sources, respective orientations and strengths of the one or more magnetic sources based on the first information, the second information, and the plurality of signals corresponding to the magnetic sensor data.

The present disclosure provides a method for optimizing a broadband noise of an inductive magnetic field sensor as well as a magnetic field sensor, including: determining a functional relationship between an induced voltage of a coil and an effective permeability of a magnetic core of the inductive magnetic field sensor; determining an equivalent voltage noise expression of a temperature variation-induced permeability noise of the magnetic core according to the functional relationship; determining a key influencing factor of the magnetic core according to the equivalent voltage noise expression of the temperature variation-induced permeability noise of the magnetic core; modifying the magnetic core according to the key influencing factor of the magnetic core to optimize the temperature variation-induced permeability noise of the magnetic core; and constructing a dual-channel composite multi-stage modulation signal-noise separation circuit to optimize a low-frequency band noise and a high-frequency band noise of the inductive magnetic field sensor.

A magnetometer with responsive material is provided that includes a PT symmetric assembly. The PT symmetric assembly includes gain material and responsive material that are positioned to achieve PT symmetry. The responsive material is configured to shift a resonance frequency of point defects in response to a magnetic field. A microwave antenna is configured to generate a microwave field of varying frequencies that engage the responsive material. A controller is configured to adjust a tunable laser source that is input into the PT symmetric assembly based on an output of the PT symmetric assembly to cause a gain generated by the gain material to match a loss caused by the responsive material. The controller is further configured to determine a strength of the magnetic field by determining one of a deviation from the exceptional point and an amplitude of the gain needed to reach the exceptional point.

A probe for locating a magnetic marker for use in surgery. The probe comprises at least two first coils (3a, 3b) and at least one second coil (5) which are arranged substantially coaxially on a longitudinal axis of the probe for measuring the proximity of a magnetic marker to the probe, and a baseline voltage taring device (7) comprising a first elongate conductor which defines a conducting path extending partially around the probe axis. The conducting path is configured and arranged such that in use the balancing magnetic field induces a balancing voltage in a sense coil that at least partially offsets the baseline voltage. Also disclosed is a method of manufacturing such a probe, a method of setting up such a probe for use in sensing a magnetic marker, and detection apparatus for locating a magnetic marker during surgery.

In described examples, an integrated circuit (IC) written on a substrate that includes a substrate surface includes a magnetic concentrator, a Hall sensor, a primary coil, and a secondary coil. The Hall sensor at least partially overlaps the magnetic concentrator. The primary coil at least partially overlaps the magnetic concentrator. The secondary coil at least partially overlaps the magnetic concentrator and the primary coil, and surrounds the Hall sensor.

The present disclosure relates to a method (100) of magnetically calibrating a magnetometer sensing system (30) with respect to an electronic device (50), the method (100) comprising: detecting (110) a disturbing magnetic source (520) in the electronic device (50) relative to a reference coordinate system (X, Y, Z) of the magnetometer sensing system (30); identifying (120) one or more magnetometers (Sk,l) of the magnetometer sensing system (30) which are magnetically affected by the detected disturbing magnetic source (520); selecting (130) one or more balancing magnetic sources (400) to reduce a magnetic effect of the detected disturbing magnetic source (520) on the one or more identified magnetometers (Sk,l); and placing (140) the one or more selected balancing magnetic sources (400) in a fixed relation to the magnetometer sensing system (30) and / or to the disturbing magnetic source (520).

Systems, circuits, and methods provide self-calibration for magnetoresistance-based magnetic field sensors. Examples can include use of a closed loop acting as a feedback or calibration loop that is configured to process a reference signal applied to one or more magnetoresistance elements in a MR-based magnetic field sensor that also detects one or more external magnetic fields. The closed loop can adjust a bias voltage applied to the one or more magnetoresistance elements based on the reference signal. The calibration loop can accordingly provide for automatic or self-calibration of sensitivity of one or more magnetoresistance elements of the sensors to compensate for external factors affecting sensitivity of the one or more magnetoresistance elements.

The invention relates to a magnetic measuring device. In a magnetic measurement device provided with a plurality of sensor units having a variable relative positional relationship, even if the relative positional relationship of the plurality of sensor units is changed, the relative positional relationship of the plurality of sensor units after the change is easily identified. A magnetic measurement device (100) is provided with: a sensor unit (1) having one or more magnetic sensors (10); a sensor unit (2) having one or more magnetic sensors (10) and one or more magnetic field generating coils (20); and a movable mechanism (4) that changes the relative positional relationship between the sensor unit (1) and the sensor unit (2).

Disclosed herein is a magnetic field measurement device that includes a first sensor unit having one or more magnetic sensors, a second sensor unit having one or more magnetic sensors and one or more magnetic field generating coils, and a moving mechanism configured to change a relative positional relationship between the first and second sensor units.

A system, comprising: a sensing element including a plurality of resistive elements; a switching matrix that is configured to change a total resistance of the sensing element by bringing online or offline one or more of the plurality of resistive elements, the total resistance of the sensing element, at any point in time, being based on respective resistances of only those of the plurality of resistive elements that are currently online; a matrix controller that is configured to detect when a value of a counter signal is updated and cause the switching matrix to change the total resistance of the sensing element by bringing offline or online one or more of the plurality of resistive elements based on the value of the counter signal; and a counter signal generator configured to detect whether an offset signal satisfies a predetermined condition and update the value of the counter signal.

Disclosed herein is a magnetic sensor that includes a sensor chip having a magnetosensitive element, a magnetic field collecting body for collecting a magnetic field to the magnetosensitive element, an excitation coil wound around the magnetic field collecting body, and a modulation circuit that supplies an excitation current having a predetermined frequency to the excitation coil so as to periodically magnetically saturate the magnetosensitive element without magnetically saturating the magnetic field collecting body.

The invention relates to a measuring device having an object (12) which can be rotated or moved in translation about an axis of rotation and a measuring system (10) for detecting a shaft movement, the measuring system (10) comprising an exciter unit (25) which is connected to the object (12) in a rotationally fixed manner and which has at least one permanent magnet exciter magnet (26); a Wiegand sensor (36) which interacts with the magnetic field of the exciter magnet (26); a magnetoresistive sensor unit (40) which interacts with the magnetic field of the exciter magnet (26) and is arranged offset and / or torsionally with respect to the Wiegand sensor (36), the magnetoresistive sensor unit (40) having a voltage divider (46, 48) with a first connection (52) and a second connection (54) for feeding the voltage divider (46, 48, 90), at least one magnetoresistive element (60, 62, 64, 64) being arranged in the first connection (52) and the second connection (54). 66) and a measurement point (70, 72), characterized in that an additional resistor (82) is electrically connected to the measurement point (70, 72), the additional resistor (82) being selectively electrically connectable to the third connection (86) or to the fourth connection (88) via a conversion unit (84), and the conversion unit (84) being electrically connected to a Wiegand sensor (36), a voltage pulse of the Wiegand sensor (36) being evaluated and implemented in such a way that the additional resistor (82) is selectively electrically connectable to the third connection (86) or to the fourth connection (88). The switching between the third terminal (86) and the fourth terminal (88) is realized according to the polarity of the voltage pulse of the Wiegand sensor (36).

The technical problem of the present invention is to provide a magnetic detection system capable of detecting metal foreign matters with high sensitivity. As a technical means for solving the technical problem, a magnetism detection system (100) is provided with: a signal generation circuit (501) that generates an excitation signal (P); an excitation coil (250) to which an excitation signal (P) is supplied; a buffer circuit (503) connected between the signal generation circuit (501) and the excitation coil (250); magnetic sensors (40A, 40B) that are disposed on opposite sides of each other in the coil axis direction when viewed from the excitation coil (250); a sample stage (300) that holds a sample (310) between the excitation coil (250) and the magnetic sensor (40A); and a detection circuit that generates a detection signal (OUT) on the basis of the difference between the output signals (Pa, Pb) output from the magnetic sensors (40A, 40B). As a result, it is possible to suppress a disorder in the waveform of the excitation signal (P) by means of the snubber circuit (503), and thus it is possible to detect a metal foreign object with high sensitivity.

In a magnetic sensor having a structure in which a magnetic sensor module is housed in a housing, damage to a magnetosensitive element during assembly is prevented. A magnetic sensor (S) is provided with a housing (2, 3), a magnetic sensor module (1) housed in the housing (2, 3), and an insulating dummy substrate (4). A magnetic sensor module (1) is provided with: an insulating substrate (10); a sensor chip (100) mounted on the upper surface (11) of the substrate (10); a terminal electrode (72) provided on the upper surface (11) of the substrate (10); a wiring pattern (82) provided on the lower surface (12) of the substrate (10); a first via conductor (V12) that is provided through the substrate (10) and connects one end of the wiring pattern (82) and the terminal electrode (72); and a second via conductor (V32) that is provided through the substrate (10) and connects the other end of the wiring pattern (82) and the sensor chip (100). The dummy substrate (4) is disposed between the inner wall of the frame (2, 3) and the lower surface (12) of the substrate (10).

The application discloses a method for improving low-frequency precision of an atomic magnetometer, and relates to the technical field of weak magnetic detection. In the method, the closed-loop atomic magnetometer is in a zero-locking state, a direct-current bias system is automatically and accurately adjusted, the atomic magnetometer is caused to work in a critical interval between a zero-locking region and a linear region, the zero-locking region has the suppression on low-frequency magnetic noise, and the linear region has a higher response to a measured magnetic field, so that the low-frequency measurement precision of the atomic magnetometer is improved. The application is suitable for an optical pumping atomic magnetometer system, and is favorable for improving the precision and stability of the atomic magnetometer, and can significantly improve the magnetic field sensitivity in the low-frequency part.

A system, comprising: a sensing element including a plurality of resistive elements; a switching matrix that is configured to change a total resistance of the sensing element by bringing online or offline one or more of the plurality of resistive elements, the total resistance of the sensing element, at any point in time, being based on respective resistances of only those of the plurality of resistive elements that are currently online; a matrix controller that is configured to detect when a value of a counter signal is updated and cause the switching matrix to change the total resistance of the sensing element by bringing offline or online one or more of the plurality of resistive elements based on the value of the counter signal; and a counter signal generator configured to detect whether an offset signal satisfies a predetermined condition and update the value of the counter signal.

Disclosed is an open-structured RF transmitting and receiving coil system including: a magnetic field generation part configured to generate a magnetic field to detect the position of magnetic particles located in a three-dimensional space; a detection part configured to receive a reflection signal from the magnetic particles receiving the magnetic field; and a cancellation part connected to the detection part and including a calibration coil.

A fully integrated micro search coil magnetometer (μSCM) with a low-noise instrumentation amplifier is provided for low-frequency magnetic field measurements in the range of 1Hz to 1kHz. A micro search coil formed by stacking planar spiral inductors and serially connecting them with an in-phase configuration is used for magnetic field measurements. The critical line width and inner diameter of a planar spiral inductor are theoretically calculated and experimentally verified, enabling the development of a unique CMOS layout. This layout incorporates the calculated critical inner diameter, significantly optimizing the area utilization on the CMOS die. Additionally, the CMOS die includes a polysilicon-layer inductor for on-chip calibration, a Hall effect sensor for DC magnetic field measurement, and a temperature sensor for enhanced functionality. The μSCM delivers a compact, energy-efficient, and highly sensitive solution for low-frequency magnetic field measurements, surpassing the performance of most commercially available Hall effect sensors.

The present disclosure provides magnetic sensor system that includes a magnetic sensing device comprising a magnetic multi-turn sensor, and a method of initializing the magnetic multi-turn sensor into a known state with a defined domain wall configuration ready for use. A strong magnetic field is first applied to fill the MT sensor with domain walls. A current is then applied to a domain wall stopping structure arranged over at least one portion of the MT sensor, and the working magnetic field (i.e., the magnetic field generated by a magnet mounted on the mechanical system) is rotated until the desired domain wall configuration is achieved. Once the desired domain wall configuration is achieved, the current applied to the domain wall stopping structure is stopped and the MT sensor is ready for use. The sensor can be initialized into a known state without needing to drive the mechanical system to a start or end position.

This application relates to a position detection device, comprising: a first Hall element; a second Hall element; a differential amplifier configured to generate a differential voltage by differentially amplifying a first Hall voltage generated by the first Hall element and a second Hall voltage generated by the second Hall element; a summing amplifier configured to generate a summed voltage by summing the first Hall voltage and the second Hall voltage; a comparator configured to compare a reference voltage with the differential voltage to generate an error voltage; and a current converter configured to generate a bias current supplied to the first Hall element and the second Hall element based on the error voltage, wherein the device is configured to detect the position of a detected object based on the summed voltage.

The invention relates to an apparatus as well as a method for calibrating a magnetic sensor system including at least one magnetic field source and one magnetic field sensor arrangement with several individual magnetic field sensors. Here, a plurality of individual measurements is performed, wherein each individual measurement provides a number of measurement values depending on the number of the individual magnetic field sensors. The magnetic field of the magnetic field source is varied at the location of the magnetic field sensor arrangement between two successive individual measurements. Based on the measurement values and by applying an optimization or estimation method, one or several magnetic field sensor-specific parameters and / or magnetic field source-specific parameters are determined, which are used as correction values for calibrating the magnetic sensor system. According to the invention, a magnetic field source is used that generates an inhomogeneous magnetic field.