Abstract: A self-tuning resonator for use in a transmitter apparatus for inducing alternating currents in a buried conductor. The resonator is dynamically tuned at frequencies below 500 kHz by exploiting the inherent voltage-variability of net capacitance in multilayer ceramic capacitors. The transmitter apparatus provides improved efficiency and induced output power suitable for use in a man-portable locator system, providing a very high magnetic field output from a physically small battery-powered resonator at frequencies under 500 kHz. The resonator exhibits a very low equivalent series resistance (ESR) and is adaptively returned to a predetermined resonant frequency responsive to any changes in resonance arising from phenomena such as component heating, thereby supporting very high tank circuit currents from battery-powered source to produce very high magnetic flux output.

Abstract: An apparatus having a position sensor for determining a position of a moveable component is provided. The apparatus comprises a housing, a positioning member, a shaped magnetic pole, a magnet, and a hall effect sensor. The positioning member, the shaped magnetic pole, the magnet, and the hall effect sensor are each disposed within the housing. The positioning member is operably coupled to the moveable component and moveable relative to the housing. The magnet induces a magnetic flux in the shaped magnetic pole. One of the shaped magnetic pole and the magnet move in conjunction with the positioning member. The hall effect sensor is adapted to sense an intensity of the magnetic flux in the shaped magnetic pole and generate an output corresponding to the sensed intensity such that the position of the moveable component can be determined.

Abstract: A magnetic sensing apparatus includes a first magnetic transducer separated spatially from a second magnetic transducer and proximate to a target and a direction decoding circuit associated with the first and second magnetic transducers, wherein the direction decoding circuit produces output pulses that provide data indicative of a rotation of the target while rejecting rotational vibration signals associated with the target during a rotational detection of the target utilizing the first and second magnetic transducers without producing erroneous output pulses or missing an excessive number of the output pulses during speed and rotational detection operations thereof.

Abstract: A system for decoding a signal of a rotating portion of a machine. The system includes a sensor configured to output N signals based on signals received from the rotating portion, and a processor configured to derive a value from a plurality of differences between sampled data obtained from the N signals.

Abstract: A device and method for validating a ticket having magnetic ink printed on at least one side of a ticket. The ink is magnetized to create a magnetic signal in the magnetic ink and thereafter a media reader sensor spaced from the ticket is used to verify the existence of a magnetic signal. The magnetic signal is comparable to pre-existing data to determine a match and/or validate tickets having a match. An optical reader can be used to obtain additional data stored in the form of bar codes or patterns on the printed magnetric ink. The optical signal is comparable to pre-existing data to determine a match and/or validate tickets having a match. Preferred comparators for magnetic and optical matching are microprocessors and preferred media reader sensors for magnetic readers are anisotropic magnetoresistive sensors.

Abstract: A flexible elongate structure, such as a flexible riser (10), comprising at least one layer (20) of steel wires near the surface which extend at least partly along the length of the structure, can be monitored by inducing a small, alternating magnetic field in the steel wires using an electromagnetic coil, and monitoring the magnetic flux density near the surface of the structure so as to asses the stress and hence detect if any wires have broken. By using an array of stress-measuring electromagnetic probes (24) around the structure some spatial resolution can be provided as to the location of any break in the wires.

Abstract: A device for detecting magnetic fields, of the type comprising at least one element made of hard 5 magnetic material (12) and an element made of soft magnetic material (13) associated an element made of semiconductor material (11), electrodes (15) for forcing a current (I) in the semiconductor material (11), characterised in that the element made of hard magnetic material (12) and element made of soft magnetic material (13) are positioned in planar fashion on the element made of semiconductor material (11).

Abstract: A scanning SQUID microscope is set forth to provide improved output imaging. The SQUID microscope includes a vertically adjustable housing adapted to securely retain a SQUID loop or sensor. A scanning stage of the SQUID microscope is adapted to support a sample while moving the sample along a predetermined path to selectively position predetermined portions of the sample in close proximity to the SQUID loop or sensor to permit the loop or sensor to detect predetermined magnetic field information provided by the predetermined portions of the sample. A position control processor coupled to the scanning stage is operative to receive and process the predetermined magnetic field information to provide corresponding position noise information. Criteria are also presented for determining the expected level of position noise under given experimental conditions.

Abstract: A pulse signal generator using a magnetic device that can cause a large Barkhausen effect, comprises means having a number of pits and projections and generates pulses according to the behavior of these, the means being capable of moving the pits and projections in a first or second direction, the pits and projections being disposed in the moving direction with some of the projections missing or some of the pits filled. The value of the ratio between the time interval of pulses generated by portions other than a projection-missing portion and the time interval of pulses generated by the projection-missing portion or the value of the ratio between the time interval of pulses generated by portions other than a pit-filled portion and the time interval of pulses generated by the pit-filled portion differs between when the pits and projections move in the first or second direction.

Abstract: The method for predicting seismic events includes supplying electricity by means of a detection unit (3) fitted with current electrodes (A, B) and potential probes (M, N) arranged in the ground and detecting electrical current and induced potentials by means of said electrodes (A, B) and said reception probes (M, N), for the calculation of resistivity in the ground. The resistivity data recorded is acquired and stored and then transferred to a means of analysis and processing (11). Finally, resistive drops in relation to preset values, corresponding to the approach of seismic events are evaluated.

Abstract: Conductive wires run parallel to each other and connect a Hall element and an ECU. The conductive wire includes an extracting part and a wiring part. The extracting part runs along a surface of a base, on which the Hall element is positioned, and in a direction of a sensitivity of the Hall element. The wiring part extends from the extracting part and runs near a rotating crankshaft in an axial direction of the crankshaft. Similar to the conductive wire, the conductive wire includes an extracting part and a wiring part. Conductive wires run parallel to each other and connect a Hall element and the ECU. The conductive wires include an extracting part and a wiring part, and an extracting part and a wiring part, respectively.

Abstract: A magnetic-sensing apparatus and methods of making and using thereof are disclosed. The sensing apparatus may have one or more magneto-resistive-sensing elements, one ore more reorientation elements for adjusting the magneto-resistive-sensing elements, and semiconductor circuitry having driver circuitry for controlling the reorientation elements. The magneto-resistive-sensing elements, reorientation elements and semiconductor circuitry may be disposed in single package and/or monolithically formed on a single chip. Alternatively, some of the semiconductor circuitry may be monolithically formed on a first chip with the magneto-resistive-sensing elements, while a second portion of the semiconductor circuitry may be formed on a second chip. The first and second chips may be placed in close proximity and electrically connected together. Alternatively the chips may have no intentional electrical interaction.

Abstract: An actuator having an output shaft, a motor for rotating the output shaft between a first position and a second position, and an electronic control module having a controller and a sensor. The sensor is configured to output a signal to the controller indicative of the position of the output shaft, and the controller is configured to determine whether the output shaft is in the first position or the second position.

Abstract: The magnetic sensor in the invention includes a detecting section that detects a change of magnetic flux due to a movement of the magnetic movable, comparator circuits constituting a converting section that converts a change of magnetic flux detected by the detecting section into an electric amount, and a D-FF circuit device, in a sensor unit having a power-supplying power terminal VB, a ground terminal GND and an output terminal VOUT. A current control section is provided to change the amount of current flowing through at least one of the power terminal and the ground terminal, correspondingly to a moving direction of the magnetic movable. Thus, a moving direction of the magnetic movable can be determined depending upon the amount of current.

Abstract: A rotation angle detector includes a rotator, a detecting rotator, a magnet, an anisotropic magnetoresistive element, an amplifier, and a controller. The controller connects an output terminal of the anisotropic magnetoresistive element to the ground so as to detect a short circuit between adjacent output terminals based on the difference in output voltage from the amplifier. When there is no short circuit, the controller releases the connection from the output terminal to the ground, and detects the rotation angle of the rotator from the output signal that is differentially amplified by the amplifier based on the output signal of the anisotropic magnetoresistive element.

Abstract: This publication discloses a method and arrangement for determining the hardening depth of steel or other ferromagnetic substances without breaking the object being measured. According to the invention, a varying magnetic field, which causes magnetic Barkhausen noise (MBN), is created in the measurement object with the aid of a magnetization coil 13. The varying magnetic field is regulated in such a way that the maximum force of the magnetic field does not exceed the coercitive force of the unhardened part of the measurement object. The MBN caused is measured with the aid of an MBN sensor. The measured signal is filtered and Fourier transformed. The signal in the frequency range is integrated over a suitable frequency band, in order to determine the value depicting the energy of the MBN. This value correlates with the hardening depth and on the basis of this value it is thus possible to determine the hardening depth.

Abstract: A position-sensing system magnetically senses the position of a piston rod moving with respect to a cylinder. A magnetically hard layer on the piston rod provides a recording medium. Information is magnetically recorded in regions of the magnetically hard layer. These regions provide a relative encoding scheme for determining the position of the piston rod. Magnetic-field sensors are positioned over redundant tracks of magnetically recorded regions. Each magnetic-field sensor positioned over a given track senses the same magnetized regions while the piston rod moves with respect to the cylinder. Other magnetic-field sensors can sense ambient fields for use in performing common-mode rejection. A write head can dynamically repair damaged or erased regions detected by the magnetic-field sensors. Energized by a battery-backup power source, the magnetic-field sensors and associated circuitry can continue to track movement of the piston rod when the machinery is off.

Abstract: Position sensing of movable elements including but not limited to machine components is disclosed. Motion of a movable element can produce motion of a magnetic field, which can be detected by magnetic sensors. The motion and/or variations of a magnetic field and/or a magnetic flux may be produced by any combination of a motion of the sensors, associated magnets, or associated magnetic material. Magnetic sensors maybe capable of measuring either rotary, or linear motion, or both. Such sensors can provide indication of an incremental position change, an absolute position, or both. Absolute position and high-resolution position sensing may be produced for measurement of either linear and/or angular motion. Suitable magnetic sensors include, but are not limited to, Hall effect devices and/or magneto-resistive elements, and may include multi-element magnetic sensors. Suitable signal conditioning and/or control means such as control electronics can be used to receive output signals from the sensors.

Abstract: A magnetic device mounts on a flat spoke of a wheel. This magnetic device can comprise a magnet and a housing. The housing is coupled to the magnet, and has a spoke-receiving recess with a non-circular cross section, and at least one detent. The detent extends from the housing into the spoke-receiving recess to secure a flat spoke within the spoke-receiving recess via a snap-fit. The magnetic device communicates with a sensing device, which is adapted to be coupled to a portion of the bicycle that is adjacent to a wheel of the bicycle. A display unit, adapted to be mounted on handlebars of the bicycle, displays the speed information obtained from the sensing device. In a second embodiment, the housing is made of a more elastic material, and the detents become optional. In a third embodiment, the spoke-receiving recess of the housing has a projection that engages a concavity form in the connecting portion of the spoke.

Abstract: A method for surface estimation of reservoir properties, wherein location of and average earth resistivities above, below, and horizontally adjacent to the subsurface geologic formation are first determined using geological and geophysical data in the vicinity of the subsurface geologic formation. Then dimensions and probing frequency for an electromagnetic source are determined to substantially maximize transmitted vertical and horizontal electric currents at the subsurface geologic formation, using the location and the average earth resistivities. Next, the electromagnetic source is activated at or near surface, approximately centered above the subsurface geologic formation and a plurality of components of electromagnetic response is measured with a receiver array. Geometrical and electrical parameter constraints are determined, using the geological and geophysical data.