Abstract: A rotation detection apparatus utilizes a bias magnet and an array of four or more sets of magnetoresistive elements, with each set producing an output potential varying according to changes of a magnetic field vector as protrusions and recessed portions of a rotor periphery move past the array, and utilizes differential amplifiers to operate on specific combinations of the output potentials for deriving a detection signal expressing rotation information. By appropriately adjusting respective positions of the sets of magnetoresistive elements and/or respective amplification factors of the differential amplifiers, suitable detection characteristics for various rotor configurations can be obtained.

Abstract: The invention refers to a measurement probe for measuring magnetization data of at least one item (7), specifically a security document comprising at least one magnetic security material (M), said measurement probe comprising at least one core free magnetizing coil (3) characterized in that at least two magnetic field sensors (4s, 4c, 8s, 8c) are disposed at both ends inside said coil (3) at its both ends. The invention relates further to an authentication device comprising said measurement probe and to an authentication method carried out by means of said measurement probe and authentication device.

Abstract: A new application of electromagnetic tomography is described directly related to the efficient recovery of oil and gas as well the removal of unwanted liquids from subsurface formations. The process involves the deployment of both surface and a single borehole magnetic dipole structures used for both transmitting and receiving low frequency electromagnetic energy. The surface antenna consists of circularly concentric arrays of small receiving solenoid antennas and the downhole system consists of one or more solenoid antenna in a single borehole. The concentricity of the surface array is centered about or in proximity to the borehole axis. The electromagnetic field radiated by the downhole antenna is received by each surface antenna. The amplitude and phase of voltages and currents received by each surface antenna is electronically processed based on the theoretical processing principles similar to what has been recently established for electromagnetic impedance tomography (EMIT).

Abstract: In a method for the detection of local displacements and rotations, a sum signal and additionally a difference signal are formed from two separately generated signals of two transducer elements (W1, W2), which are spaced from each other, and subsequently the formed sum signal and the formed difference signal are OR-operated. A device for doubling the local frequency of moving incremental scales comprises an encoder (1a, 1b, 1c), a magnetically sensitive transducer (9, 13), and a signal conditioning stage (6a, 6b) electrically connected thereto. The transducer comprises at least two sensorially active functional groups synchronously using sensorially active groups or sub-groups (W1, W2) which are locally offset in relation to each other by a local phase ? in order to scan the moving scale, and the functional groups comprise means enabling at least two independent partial signals S1=V*sin(?t) and S2=?V*sin(?t)+?) to be produced.

Abstract: A passive blade detection sensor exploits the electrically conductive trait of typical turbo machinery components such as fan, compressor and turbine blades. A permanent magnet is placed strategically adjacent to a wire coil to generate a single pulse/antipulse signal when a blade passes in front of the sensor. The electrically conductive blade allows eddy currents to flow briefly as it passes through the magnetic field, the local reluctance is momentarily increased, and the magnetic field is momentarily changed. The coil is sensitive only to the portion of change through its cross section, so that a simple voltage pulse, useful for precise timing of blade passage, is produced. The present disclosure also describes an open-loop and closed-loop active cooling system. The cooling system includes a casing, having internal sensing components and an inlet, coupled to one end of the casing.

Abstract: A transverse induction transmitter on an instrument induces currents in an earth formation when it is pulsed. Transient measurements made at transverse and axial receivers are used for determination of a distance to a bed boundary. This may be used to control the drilling direction. Alternatively, a transmitter on an instrument having a conductive body induces currents in the earth formation. Transient signals are measured and the effect of the conductive body is removed by using a reference signal measured in a homogenous space.

Abstract: An inductive sensor unit for detecting the position of a vehicle seat or for a gate-shifting unit of an automatic transmission, is described. The inductive sensor unit has a plurality of sensor coils that are disposed in planar fashion on a printed circuit board. A conductive actuation element which is guided, spaced apart, on a path over the sensor coils, and an electrical evaluation circuit detects changes in inductance of the sensor coils in accordance with a path position of the actuation element and converts the changes into electrical signals, corresponding to seat position signals or gear shifting signals. The conductive actuation element is guided, spaced apart on both sides, over the sensor coils, and in one aspect of the invention, the electrical evaluation circuit detects the inductances of all the sensor coils (L1, . . . , Li) and converts them by means of an algorithm into a current path position of the actuation element.

Abstract: In a magnetic rotation angle sensor for detecting a rotation angle of a detection target, a yoke covers outer circumferences of a magnet and a Hall device. One of the magnet and the magnetic flux density detection device rotates together with the detection target. The Hall IC is radially shifted from a rotation center of the detection target. The magnetic flux density detection device has a detection surface that is in parallel to one of a tangential direction and a normal direction of a turning circle. The magnet is magnetized in the one of the tangential direction and the normal direction of the turning circle.

Abstract: A locator and marking apparatus comprises a housing and a surface on the housing for holding a magnet to be dispensed. Spacer members are formed on the housing such that the surface for holding the magnet is maintained a substantially predetermined distance from a substrate on which the locating and marking apparatus is positioned.

Abstract: A stationary yoke surrounds an outer peripheral surface of a ring-shaped permanent magnet in a certain distance. The ring-shaped permanent magnet is fixed to a rotor and has two poles of N, S poles in a diameter direction. The stationary yoke includes a first outside yoke and a second outside yoke overlapped in an axial direction and a hole element is disposed in a gap of the first outside yoke. An axial height of the first outside yoke changes along the circumferential direction and a height of the second outside yoke has a complementary relation with the height of the first outside yoke, and the first outside yoke and the second outside yoke are overlapped in a certain clearance.

Abstract: A device in which the receiver coil of a pulse inductive metal detector is capable of switching between a differential configuration (i.e., gradiometer configuration) to a non-differential or summing configuration under control of the operator or computer.

Abstract: A method and apparatus to screen individuals specifically for paramagnetic or ferromagnetic objects they may be carrying or wearing, before they enter a controlled area. The device comprises a screening portal, including multiple sensor arrays and associated electronics. The device places the sensor arrays in close proximity to a subject's body, including the head and feet if desired, for screening purposes. The portal can have multiple excitation sources oriented to generate a multi-axis excitation field, and multi-axis sensors. The portal can also have an interlock with the door of the controlled area.

Abstract: A method and system for calibrating a magnetic compass and/or verifying a compass calibration, using a calibration magnetic field produced by a field-generating coil within the magnetic compass is described. The field-generating coil is located near magnetometers within the magnetic compass. Passing a self-trimming current through the coil produces a magnetic field that acts on the magnetometers. Samples of an output signal from each magnetometer are taken to obtain digital values that indicate the output signal from each magnetometer. The digital values are used by a processor to determine one or more calibration coefficient for using calibrating the magnetic compass. The samples of the output signals are taken when a self-trimming current is passing through the coil and when the self-trimming current is not passing through the coil.

Abstract: A position sensor for sensing linear or radial position including at least two magnetic conductive structures, at least two magnets and a magnetic flux responsive device. The at least two magnetic conductive structures, include a first magnetic conductive structure and a second magnetic conductive structure. The first magnetic conductive structure being substantially parallel with the second magnetic conductive structure. The at least two magnets, including a first magnet and a second magnet. The first magnet being in contact with the first magnetic conductive structure and with the second magnetic conductive structure. The second magnet being in contact with both the first magnetic conductive structure and the second magnetic conductive structure. The magnetic flux responsive device constrained to travel a path that is partially located between the first magnetic conductive structure and the second magnetic conductive structure, with the path extending beyond at least one of the at least two magnets.

Abstract: A device and method to improve pulse inductive metal detector (MD) sensitivity uses multiple, current steps to reduce the voltage rating of electronic components. Current reduction in one implementation is done with multiple switched resistors coupled to a voltage source and connected to the transmitter coil. The current reduction in another implementation is done with multiple switched current sources that are connected to the transmitter coil and are switched inactive one by one to reduce the total current to the transmitter coil. The current is stepped down in rapid secession with a time delay between current transitions less than the time constant of the metal target under investigation.

Abstract: An apparatus for sensing the proximity of a first vehicle (79) to an object such as a second vehicle (82). The apparatus includes an array of sensor assemblies (80) mounted on the first vehicle (79). The sensor assemblies (80) include Hall effect sensors (184). The array of sensor assemblies (80) provide an output signal when located within the proximity of the second vehicle (82).

Abstract: Disclosed is a magnetic field sensor of high sensitivity, and which is power-saving and can be manufactured with low cost in a very small size. The magnetic field sensor includes a soft magnetic core formed to construct a closed-magnetic circuit on a semiconductor substrate, a magnetic field sensing coil formed by a metal film in a shape that winds the soft magnetic core, and a drive line for exciting the soft magnetic core by directly applying an electric current thereto. The drive line is formed in a rectangular angle to the magnetic field sensing coil, and connected to the both ends of the soft magnetic core in a length direction.

Abstract: A method and system to detect a position of a member movable along a defined path is described. The system includes a magnetic source, an array of sensors, and an analyzer. The magnetic source radiates a magnetic field and is coupled to a movable member. The array of sensors is fixed relative to the movable member. Each sensor generates an output response value based on an angle of the magnetic field passing through each sensor. The array of sensors produces a plurality of output response values for a first position of the movable member. The analyzer receives the plurality of output response values and calculates a composite output response value to determine the first position of the movable member.

Abstract: Rotation detecting apparatus for detecting rotation of a magnetic rotor includes: a sensor chip having a magnetoresistive device; and a bias magnet. The magnetoresistive device is capable of detecting change of a magnetic vector near the sensor chip so that the rotation detecting apparatus detects the rotation of the magnetic rotor. The change of the magnetic vector is generated by the bias magnetic field and the rotation of the magnetic rotor. The bias magnet is disposed around the sensor chip so that a deflection angle of the magnetic vector is controllable.

Abstract: Apparatus and methods for detecting passing magnetic articles including an offset adjustment circuit for adjusting the DC level of the magnetic field signal based on a dynamically adjustable offset threshold signal. The detector includes a PDAC for tracking the positive peaks of a magnetic field signal and an NDAC for tracking the negative peaks of the magnetic field signal. In one embodiment, the offset threshold signal includes a positive offset threshold signal and a negative offset threshold signal that are initially set at fixed respective signal levels and that become the level of the PDAC signal and NDAC signals, respectively, in response to a counter, that counts a number of increments of the PDAC signal and decrements of the NDAC signal, reaching a predetermined count value.