Abstract: A rotary position sensor featuring a magnetized rotor which produces a magnetic flux density that varies sinusoidally with respect to the angular position of the rotor, which may be either a selectively magnetized ring or disk. The magnetic flux density produced by the rotor is measured by a sensor that responds in a linear fashion to the magnitude of the radial component of the magnetic flux density. Typical embodiments would use magnetic flux density sensors, as for example either linear Hall sensors or magnetoresistive type sensors. The measured magnetic flux densities are then used as in a traditional resolver to compute position or used to directly generate control signals to operate, for example, a motor.

Abstract: A magnetic incremental motion detection system (110) for outputting a plurality of voltage and/or current signals in digital form wherein the voltage and/or current signals are a collective representation of any incremental rotational, linear, or pivotal movement of an object. A target (120) of the system (110) is adjoined to an object to synchronously move with the object. A plurality of indications (121c, 121d) are adjoined to the target (120), and uniformly and serially disposed along an area (121a) of a surface (121) of the target (120). The system further comprises one or more magnetic sensors (80, 180) spatially positioned from the area of the surface to define air gap areas therebetween. Each of the magnetic sensors (80, 180) are operable to output an analog signal in response to a synchronous movement of the target with the object, and one of two digital circuits (85, 185) output a digital signal in response to the analog signal.

Abstract: A non-contact type displacement sensor is provided with a housing, a rotational shaft being in an approximately cylindrical hollow shape, a magnetic circuit forming member disposed in an inner space of the rotational shaft, and a magnetic sensing element supported by a housing so as to be positioned on a central axis of the rotational shaft in a space enclosed by the magnetic circuit forming member, wherein the magnetic sensing element is not displaced.

Abstract: In order to provide a position measuring system, comprising a transmitter, a sensor with an inductive element to which the transmitter is coupled electromagnetically and an evaluating unit, wherein the sensor and the transmitter are adapted to be positioned relative to one another, whereby said position measuring system will be of simple construction and can thus be manufactured economically while being employable universally, provision is made for the inductive element to be coupled to an oscillator which is affected by the Q factor and/or the effective inductance of the inductive element, for the Q factor and/or the effective inductance of the inductive element to be determined by the size of an effective sensor region to which the transmitter is coupled, and/or by the size of an effective transmitter region which is coupled to an effective sensor region, and for the sensor and/or the transmitter to be formed in such a manner that the size of the effective sensor region to which the transmitter is coupled,

Abstract: An optical demultiplexer has a coarse filter 41,43,45 and a plurality of arrayed waveguide gratings (AWGs) 49 connected to respective outputs of the coarse filter 41,43,45. The AWGs are of like design with a plurality of configurations and are arranged to have a configuration corresponding to be frequency range output on the respective output. The device can be used in WDM systems.

Abstract: An apparatus for obtaining resistivity images of a borehole includes an array of measure electrodes separated from a pad or the body of the instrument by a focusing electrode. The focusing electrode is maintained at a slightly higher potential than the measure electrodes. The apparatus is primarily intended for use with conducting fluids but may also be used with non-conducting fluids. A modulated electrical current with a carrier frequency of 1 MHz is injected into the formation. When used with a non-conducting fluid, capacitive coupling between the electrode and the conductive formation is provided by the dielectric of fluid. When used with a conducting borehole fluid, an additional capacitor may be incorporated into the circuit. The current in the measure electrode is indicative of the conductivity of the formation.

Abstract: A drill collar structure to facilitate measurement-while-drilling (MWD) techniques while at the same time having sufficient rigidity to facilitate the drilling operation is disclosed. In some embodiments, a metal structure involving openings such as slots, preferably oriented longitudinally along its axis, but also in other configurations, are disclosed to allow sufficient strength while at the same time allowing exit and entrance of electromagnetic energy. A composite structure is also disclosed which, for given layers, has adjacent fibers such as glass and carbon, so that when the layers are overlapped, glass areas overlap glass areas throughout the radial thickness of the composite tube to create “windows” for the entrance and exit of electromagnetic energy. In yet other embodiments, the drill collar can be made of a metallic frame structure with a multiplicity of openings which are filled with a composite material.

Abstract: A conductivity meter for measuring conductivity of terrain, including a first transmitter coil, a signal generator connected to the first transmitter coil to supply a time-varying current thereto for inducing eddy currents in the terrain, a first receiver coil horizontally spaced from the first transmitter coil, a temperature sensing device for measuring temperature, and a signal processor, including a memory storing a plurality of temperature dependent correction values, for isolating from a signal received by the first receiver coil a secondary signal representative of a secondary magnetic field generated in the terrain by the eddy currents, and determining an apparent terrain conductivity based on the isolated secondary signal and a selected temperature dependent correction value selected from the stored temperature dependent correction values according to a measured temperature received from the temperature sensing device.

Abstract: An angular position sensor is provided including a rotatable magnet and at least one magnetically sensitive device. The at least one magnetically sensitive device is preferably a plurality of Hall effect sensors disposed on a circuit board for processing the generated electrical signals. The present invention includes a pair of focusing members designed to transmit and uniformly focus a magnetic field across the magnetically sensitive device, wherein the focusing members are tailored to be substantially planar and provide a uniform magnetic field gradient across the magnetically sensitive device. In a preferred embodiment, the present invention also includes at least one shielding member. The angular position sensor may be adapted for use in a control system for the electronic monitoring and control of the throttle plate position in a motor vehicle.

Abstract: A vehicle suspension strut is disclosed that includes a housing having a chamber and a piston slidably disposed in the chamber. A piston rod is connected to the piston and extends out of the housing. The piston rod includes a bore extending longitudinally therein. A magnetostrictive transducer provides an output signal indicative of the piston position with respect to the housing. The magnetostrictive transducer includes a magnetostrictive waveguide disposed in the bore and a magnet joined to the housing that is operably coupled to the magnetostrictive waveguide and the magnetostrictive waveguide abruptly terminates at one end.

Abstract: An electromagnetic tomography system for determining properties of geological formation penetrated by at least one borehole lined with a conductive tubular includes a transmitter disposed in a first borehole and adapted to induce a magnetic field, a first receiver disposed in the first borehole and adapted to detect a magnetic field induced in the conductive tubular by the transmitter, and a second receiver adapted to detect a magnetic field induced in the geological formation by the transmitter.

Abstract: An electronic circuit for automatically compensating for errors in the output signal of a displacement sensor. The electronic circuitry includes an analog to digital converter for converting an analog output signal from a linear displacement type sensor. The digital output signal from the sensor is processed by a microcontroller which automatically compensates for errors in the output signal. Ideal values, stored in an electronic memory, are used for compensation.

Abstract: The thickness of a conductive film formed on a substrate can be measured efficiently at low cost with a film thickness measuring apparatus of the invention, which includes an eddy current coil sensor, disposable at a predetermined position near a conductive film, for generating a predetermined eddy current in the conductive film and for detecting a magnetic field caused by the eddy current. The apparatus also includes a displacement sensor for measuring a displacement between the eddy current coil sensor and the conductive film. The thickness of the conductive film is measured in accordance with a variation in inductance of the eddy current coil sensor and the amount of displacement measured by the displacement sensor.

Abstract: A bearing provided with an annular means generating magnetic pulses and with a device for detecting these pulses, wherein the detection device comprises a plurality of aligned sensitive elements. The sensitive elements are placed equidistantly from one another and the detection device comprises an even number 2N of sensitive elements.

Abstract: A device for triggering ignition circuits is used to increase safety without additional expenditures in the form of hardware or wiring. Plus and minus output elements of various ICs are used for this purpose. Ignition circuit diagnosis is now also distributed over two ICs. Ignition circuit diagnosis includes, in particular, the resistance measurement of the respective ignition circuit. Each substrate, in other words IC, therefore has at least one plus and one minus output element.

Abstract: A device for locating a metallic stud disposed within a wall. The device comprises an elongate housing which itself comprises a base portion defining a generally planar contact surface and a handle portion which extends from the base portion. In addition to the housing, the device comprises at least one magnet which defines a generally planar attraction surface. The magnet is disposed within the base portion of the housing such that the attraction surface extends in generally parallel relation to the contact surface. The magnet and the housing are sized relative to each other such that the force of magnetic attraction between the magnet and the stud when the device is oriented in a particular location upon the wall is sufficient to maintain the device thereon without external support.

Abstract: A magnetic field probe includes a substrate and a conductive layer provided on the substrate. The conductive layer has a coil, lead wires, and pads. The coil has at least one turn and outputs a signal indicative of a magnetic field from a device under test in a vicinity of the magnetic field probe. The lead wires extend from the coil to the pads, the signal from the coil being transmitted to the pads through the lead wires. An isolating layer of a dielectric material is provided on the lead wires to protect the lead wires between the coil and the pads in the conductive layer. A shielding layer of a conductive material is provided on the isolating layer to protect the isolating layer. The shielding layer prevents distortion of the magnetic field at the lead wires in conjunction with the isolating layer.

Abstract: An apparatus and a method for centering a core of a waveguide amplifier. One embodiment of the invention comprises axially rotating a waveguide which has a core, shining a light through a light transmission pathway in the core of the waveguide, and shaping an outer surface of the waveguide in a predetermined pattern with respect to the light transmission pathway.

Abstract: A sensor assembly senses one of position, velocity, acceleration or change of acceleration. The assembly includes at least one magnet having a north and south pole and a magnetic axis defined therebetween; a magnetic flux responsive device, the at least one magnet being fixedly adjacent to the magnetic flux responsive device; and a ferrous target selectively movable relative to the at least one magnet.

Abstract: An above ground locator includes an apparatus for determining the strength of the locating signal at a selected point relative to the boring tool. The apparatus includes an antenna arrangement configured for measuring the strength of the locating signal at the selected point along first and second orthogonally opposed receiving axes to produce first and second received signals. A phase shifting arrangement phase shifts the first and second received signals in a predetermined way to generate first and second phase shifted signals, respectively. Thereafter, a summing arrangement adds the first and second phase shifted received signals to generate an output signal which is a vector sum of the first and second received signals. In one feature, third and fourth signals derived from the first and second signals are used to eliminate balance point ambiguity which is present using the first and second signals alone.