A magnetic sensor system includes a magnetic sensor device and a signal processing circuit. The magnetic sensor device generates first to third detection signals corresponding to components in three directions a field generated by a magnetic field generator that is able to change its relative position with respect to the magnetic sensor device. The signal processing circuit includes first and second processors. The second processor generates sphere information and transmits it to the first processor. When coordinates representing a set of values of the first to third detection signals in an orthogonal coordinate system are taken as a measurement point, the sphere information includes data on center coordinates of a virtual sphere having a spherical surface approximating a distribution of a plurality of measurement points. The first processor detects a change in offsets of the first to third detection signals by using the sphere information transmitted from the second processor.

The present invention relates to a field-sensor device comprising a reference field sensor providing a reference sensor signal in response to a field, a calibrated field sensor providing a calibrated sensor signal in response to the field, a reference circuit connected to the reference field sensor and adapted to receive a reference signal, and an adjustable circuit connected to the calibrated field sensor and adapted to receive a calibrated signal. When the adjustable circuit is adjusted with the calibrated signal, said calibrated signal being different from the reference signal, the calibrated field sensor provides a calibrated sensor signal substantially equal to the reference sensor signal. The field sensor device is arranged to be exposed, when in a calibration mode, to a uniform calibration field and, when in operational mode, to an operational field being a field gradient.

The present disclosure provides, in part, methods for high spatiotemporal resolution self-sorted 4D MRI. These methods can be used to improve resolution of abdominothoracic MRI during breathing by facilitating the sorting of information corresponding to individual MRI pulse sequences according to phase within the respiratory cycle. An image of the anatomy for a particular phase within the respiratory cycle is then determined using both information corresponding to the particular phase and high-frequency MR imaging information corresponding to other respiratory phases. This method provides an increase in image resolution by sharing information at high frequencies in k-space, which may be less thoroughly sampled during any particular respiratory phase, between different respiratory phases. Methods herein also permit use of DC information from individual MRI pulse sequences to determine respiratory tissue motion and to use this tissue motion information to sort the individual MRI pulse sequences according to respiratory cycle phase.

Methods and apparatus for processing a signal comprise at least one circuit configured to generate a measured signal during a measured time period and a reference signal during a reference time period. Also included is at least one dual- or multi-path analog-to-digital converter comprising at least a first processing circuit configured to process the measured signal, at least a second processing circuit configured to process the reference signal, and a third processing circuit configured to process both the measured signal and the reference signal.

Methods and apparatus for processing a signal comprise at least one circuit configured to generate a measured signal during a measured time period and a reference signal during a reference time period. Also included is at least one dual- or multi-path analog-to-digital converter comprising at least a first processing circuit configured to process the measured signal, at least a second processing circuit configured to process the reference signal, and a third processing circuit configured to process both the measured signal and the reference signal.

A magnetic field calibration device is used to calibrate a magnetism measurement device having a plurality of magnetic sensors and includes a first holder having a first holding surface, a second holder having a second holding surface having a fixed relative positional relation with the first holding surface, and magnetism generating parts fixed to the first holding surface and the second holding surface. Thus, calibration can be completed with a single operation by assigning the first and second holding surfaces of the magnetic field calibration device respectively to the first and second measurement surfaces of the magnetism measurement device. In addition, since the relative positional relation between the first and second holding surfaces is fixed, measurement results obtained from the individual measurement surfaces match each other.

A magnetic sensor comprises a magnetic detection unit that outputs a signal by applying a magnetic field, and a signal correction unit that corrects the signal output from the magnetic detection unit. The magnetic detection unit includes a magnetoresistive effect element having a predetermined sensitivity axis. The signal correction unit generates a corrected signal by correcting the signal using a correction value capable of reducing the distortion error included in the signal output from the magnetic detection unit when the magnetic field having an intersecting direction that obliquely intersects the sensitivity axis is applied to the magnetoresistive effect element.

There is provide a magnetic field measurement device including: a magnetic sensor array configured by a plurality of magnetic sensor cells, each of which has a magnetic sensor; a magnetic field acquisition section configured to acquire measurement data measured by the magnetic sensor array; a signal space separation section configured to perform signal separation to separate, into internal space data and external space data, a spatial distribution of a magnetic field which is indicated by the measurement data, based on a position and a magnetic sensitivity of each magnetic sensor; and a calculation processing section configured to remove, from the internal space data, at least a part of a variation component common to magnetic field measurement data that indicates the spatial distribution of the magnetic field which is indicated by the measurement data, and the external space data.

A test apparatus tests a wafer under test on which devices under test each including magnetoresistive memory or a magnetic sensor are formed. In a test process, the wafer under test is mounted on a stage. In the test process, a magnetic field application apparatus applies a magnetic field B.sub.EX to the wafer under test. A test probe card is used in the test process. Multiple magnetization detection units are formed on a diagnostic wafer. In a diagnostic process of the test apparatus, the diagnostic wafer is mounted on the stage instead of the wafer under test. Each magnetization detection unit is capable of measuring a magnetic field B.sub.EX generated by the magnetic field application apparatus. In the diagnostic process, the diagnostic probe card is used instead of the test probe card.

The test apparatus tests a wafer under test on which devices under test each including magnetoresistive memory or a magnetic sensor are formed. In a test process, the wafer under test is mounted on a stage. A test probe card is configured such that it can make probe contact with the wafer under test in the test process. A wafer connection HiFix is arranged between the test probe card and a test head. A magnetic field application apparatus is provided to the wafer connection HiFix. In the test process, the magnetic field application apparatus applies a magnetic field B.sub.EX to the wafer under test.