Abstract: A method and apparatus for detecting magnetic fields in which a string (1) carries an alternating current. The displacement of the string from its unperturbated position due to a magnetic gradient across the string is detected by pick-up coils (L1, L2). The signals from the pick-up coils are demodulated using a signal derived from the alternating current to produce an output.

Abstract: A magnetic test module runs on a spin stand to detect amplitude decay and noise evolution at the same time. Signal-to-noise ratio (SNR) decay is directly measured. The recording performance is correlated better with SNR instead of signal only. The thermal stability of the system is evaluated more accurately with this SNR decay method. A heater is placed under the media disk, and a remote sensing thermometer and temperature controller form a subsystem to set up desired environmental temperature. The heater creates a heated band and the read/write head flies above the heated band. The temperature control system may be removed when SNR decay measurement is performed under room temperature.

Abstract: A metrology instrument includes an eddy current sensor that is mounted to and concentric with a confocal distance sensor. By measuring the precise vertical placement of the eddy current probe with respect to the surface of the sample using the confocal distance sensor, the accuracy and precision of the eddy current measurement is improved. Because the confocal distance sensor and the eddy current sensor are confocal, there is no need to move the relative lateral positions between the sample and instrument, between the distance measurement and the eddy current measurement, thereby reducing error in the measurement as well are maximizing the throughput by minimizing the required stage travel for a single measurement.

Abstract: A device for angle measurement, having at least one transducer wheel and at least one sensor, including at least one sensor element and cooperating with the transducer wheel, in which by means of the cooperation of the transducer wheel and the sensor, a pair, which can be associated with an angle to be measured, comprising one sine-wave signal and one cosine-wave signal can be obtained, in which at least two sensors are provided, whose sine-wave signals and cosine-wave signals, for obtaining an averaged sine-wave signal and averaged cosine-wave signal, and/or after the formation of an arc tangent signal from the respective averaged or unaveraged sine-wave signals or cosine-wave signals, can be put computationally into relation with one another by means of an evaluation device in order to obtain an averaged arc tangent signal.

Abstract: A method and apparatus for determining volume and anisotropy field distribution of thin film granular material includes the use of a magneto-optic probe, a lock-in amplifier, and a computer. The magneto-optic probe utilizes the Kerr effect in order to determine the transverse AC susceptibility of the sample. The Lock-in amplifier determines the complex parameters of the susceptibility as a function of the DC field and AC frequency. Separate distribution values of anisotropy field and grain volume can then be determined mathematically from the relationship of complex susceptibility parameters to the DC field strength.

Abstract: A sensor coil for a non-contacting inductive displacement sensor, having two inner substantially identically formed winding sections (1), with an unwound section (2) provided between the two inner winding sections. Also, the coil has two outer substantially identically formed winding sections (3), which are respectively arranged at the ends of the two inner winding sections (1) facing away from the unwound section (2). The two outer winding sections (3) have a larger number of windings than the two inner winding sections (1), thereby producing a measuring signal which is substantially linear along the measuring range.

Abstract: Disclosed here is a rotation angle detector capable of detecting unusual value as a rotation angle so as not to output incorrect data. According to the rotation angle detector of the present invention, the first detector, the second detector, and the auxiliary detector rotate at a different speed. Receiving each detecting signal from i) the first and second rotation-detecting sections; ii) the second rotation-detecting section and the auxiliary rotation-detecting section; and iii) the first rotation-detecting section and the auxiliary rotation-detecting section, the controller calculates at least two tentative values for determining the rotation angle of the rotator. When the calculation values are within a predetermined range, the controller determines the detecting signal from the first and second rotation-detecting sections to be the rotation angle of the rotator.

Abstract: The system and method provides a means for inspecting pipelines that have obstructions which prevent conventional inspection pigs from passing the obstructions. The invention uses remote-field eddy current inspection techniques and a uniquely configured excitation coil for inline inspection of pipelines having valves and other fittings that severely restrict or prevent the use of conventional inspection pigs. A unique collapsible excitation coil and a collapsible sensor array enables an inspection pig using these features to pass pipeline obstructions that prevent passage by conventional inspection pigs. The collapsible coil and sensor array provide means for reducing the diameter of an inspection pig to enable it to pass obstructions in the pipeline.

Abstract: A porous geological formation contains electrolytic fluid. During the geophysical prospecting of the formation, a region of interest of the formation where the electrolytic fluid is found is stimulated with an excitation signal. The excitation signal corresponds to an energy of a first type. The excitation signal is converted in the region of interest into a response signal. The response signal corresponds to an energy of a second type. The response signal is detected. An electric polarisation is applied to the region of interest so as to strengthen the response signal relative to what it would be in the absence of polarisation. The electric polarisation comes about by means of a continuous or quasi-continuous polarising electric field. The polarising electric field is modulated in frequency with a frequency which is low relatively to the excitation frequency.

Abstract: A device, system and method for adaptively tracking amplitude boundary values of a real time sensor output signal. In accordance with the method of the present invention, an amplitude boundary value, which may be a peak or min amplitude value, representing the current amplitude boundary of the sensor output signal is stored within a digital counter. A two-tap DAC is utilized to convert the digitally stored amplitude boundary value into a reference signal level corresponding in amplitude to the amplitude boundary value. The DAC also converts the amplitude boundary value into an offset reference signal level corresponding in amplitude to the amplitude boundary value offset by a specified multiple of the DAC resolution. The reference signal level and offset reference signal are compared with the real time sensor signal and the digitally stored amplitude boundary value is adjusted in accordance with which reference signal level exceeds the real time sensor signal.

Abstract: A method, system and inductive device for accurately determining inclination of a shaft arranged with a gear wheel including a plurality of gear teeth. The inductive measuring device includes a transmitter coil and at least two receiving coils arranged adjacent relative an axis of symmetry of the transmitter coil. Voltages in the receiving coils are measured, summed and integrated. A zero value for the integral is used to determine the position of the center line of the gear tooth. The invention may be used for diagnostic and/or control purposes of an internal combustion engine.

Abstract: A speed measuring system comprising at least one stationary speed sensor (4) for detecting a speed of a measuring body (1) rotating relative to the speed sensor (4) wherein the measuring body (1) is provided, on its periphery, with electric or magnetic discontinuities. The speed sensor (4) situated at a defined distance from the measuring body (1), reacts to the discontinuities when the measuring body (1) is moved past the speed sensor (4). The speed measuring system has, in addition, one separate distance sensor (5) for determining an actual distance (LS) and an actual change in distance between the speed sensor (4) and the measuring body (1). In an evaluation device of the speed measuring system the speed of the measuring body (1) is formed from an actual output signal of the speed sensor (4) according to an actual output signal of the distance sensor (5).

Abstract: A variable reluctance resolver has a rotor with magnetic poles with 2× or greater axis combination angles, and is structured so that reliable and accurate zero point detection can be carried out. Concave and convex portions are provided on at least two, but fewer than all, of the magnetic poles of the rotor, and the zero point detection winding is provided on a plurality of electrical poles of the stator. Two or more zero point detection signals are generated simultaneously by a plurality of zero point detection windings. Therefore, even if a portion of the zero point detection signals is lost, the zero point can still be identified based on the correlation between the two or more zero point detection signals.

Abstract: In a sensing apparatus, and a control method of a sensing apparatus, the sensing apparatus includes a fluxgate including a driving coil for exciting a magnetic substance core with a current, first and second current amplifiers for applying the current to first and second ends of the driving coil, a pulse generator for generating a pulse to turn on/off the first and second current amplifiers, and a pulse controller for outputting a control signal allowing the pulse to be applied to the first and second current amplifiers, the pulse controller outputting the control signal at a start of a sensing cycle, the fluxgate generating an analog signal due to the excited magnetic substance, and an A/D converter for converting the analog signal from the fluxgate into a digital signal, wherein the pulse controller stops outputting the control signal when the A/D converter outputs the digital signal to the pulse controller.

Abstract: An eddy current monitoring system may include an elongated core. One or more coils may be coupled with the elongated core for producing an oscillating magnetic field that may couple with one or more conductive regions on a wafer. The core may be translated relative to the wafer to provide improved resolution while maintaining sufficient signal strength. An eddy current monitoring system may include a DC-coupled marginal oscillator for producing an oscillating magnetic field at a resonant frequency, where the resonant frequency may change as a result of changes to one or more conductive regions. Eddy current monitoring systems may be used to enable real-time profile control.

Abstract: A rotation detection sensor, which is a wheel-speed sensor, has a detection unit placed in a metal capped cylindrical casing and a holder fit in an opening of the casing. A flange is provided along the entire edge of the opening of the casing. Between the flange and the holder, a viscoelastic liquid gasket is entirely applied. The edge of the opening of the casing and the exposed part of the holder are covered with a resin portion. Thus, the viscoelastic liquid gasket smoothly enters the gap between the casing and the holder to ensure the gap is closed. Moreover, since the viscoelastic liquid gasket is quickly cured owing to its solvent which is speedily volatilized, the gasket exhibits a good workability. Then, after the solvent is volatilized, a rubber-based elastic sealing material is produced. The sealing material thus withstands any temperature change without problem, it never occurs that the sealing material melts to leak out, and the sealing between the casing and the holder can be ensured.

Abstract: A movable target having individually identifiable magnetic irregularities and a stationary magnetosensitive array and circuit for sensing the magnetic irregularities to thereby provide position of the moveable target relative to a fixed initial location. A method to determine a present position of the target origin including the steps of: identifying a magnetic irregularity of the moveable target; determining a first distance, Y, equal to a distance of the identified magnetic irregularity to a target origin; determining a second distance, X, equal to a distance of the identified magnetic irregularity to the array origin; and determining a distance, L, of the target origin with respect to the fixed initial location, according to a relation: L=L0+X?Y.

Abstract: A rotation detecting apparatus including a drive gear rotatably supported by a case and capable of rotating cooperatively with an object to be detected, driven gears and rotatably supported by the case and brought in mesh with the drive gear, magnets provided at rotational center portions of the driven gears and having plane portions formed with N poles and S poles, a circuit board arranged at the case and capable of being connected to outside, magnetic reluctance elements attached to the circuit board and opposed to the plane portions of the magnets and an electronic circuit part for convertion output signals of the magnetic reluctance element into rotational angle signals, wherein the magnets of the driven gears are formed with the N poles and the S poles by magnetizing the magnets after having been subjected to insert molding by a resin.

Abstract: A steering output part is fixed with a worm wheel for power assist. By a spur gear formed on the worm wheel, an input gear of a detecting unit is rotated with a speed increase. Within the detecting unit, provided is a speed-reducing mechanism for speed-reducing the rotation of the detecting shaft. By this speed reduction, a detection rotating member provided in a case rotates at an angle of 1:1 to the rotation of the steering output part, a rotation angle of which is detected by a detecting element.

Abstract: A device for measuring the angle of rotation of a rotating member of a machine, comprising a signal transmitting rotor which includes a magnet rim consisting of magnets having alternatingly arranged south poles and north poles and being moved with respect to a stationary measuring sensor is characterized in that each magnet or each magnet zone has a thickness which varies substantially sinusoidally in circumferential direction, having its maximum in the pole center of each magnet and/or forms an air gap with the measuring sensor varying sinusoidally in circumferential direction.