Abstract: A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

Abstract: A sensor for sensing the rotation of an output shaft of a motor used for driving a vehicle includes a disc on the output shaft that carries magnets facing toward a motor carrier and the motor. The motor carrier has an annular recess open on a side facing away from the motor, and a Hall effect sensor is placed in this recess and held with a T-shaped bracket having a tang that supports the Hall effect sensor partially in this annular recess for protecting it and positioning it adjacent the magnets on the disc.

Abstract: A magnetic field sensor comprises a transducer element, which: transducer element is a Spin Tunnel Junction, comprising a first and second magnetic layer which are sandwiched about an interposed electrical insulator layer; the sensor comprises a yoke having two arms; and the first magnetic layer is in direct contact with a first portion of a first arm of the yoke.

Abstract: A sonde is movable lengthwise in and relative to tubular structure such as a drill collar; slits extend through the tubular structure; and antennae coils on the sonde come into registration with the slits, for transmitting electromagnetic energy into the underground formation via certain slits, and for receiving such transmitted energy back through other of the slits, for processing.

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: A sensor system for sensing a rotation of a sensing wheel is disclosed. The sensor system has a sensing coil in juxtaposition with the sensing wheel. Moreover, the sensing coil has a sensing coil output signal indicative of the rotational speed of the sensing wheel. Further, a cancellation coil is located remotely from the sensing coil and connected in series therewith. Additionally, the cancellation coil has a cancellation coil output signal indicative of an environmental disturbance which is effecting the sensing coil output signal. The cancellation coil output signal operates to cancel the effects of the environmental disturbance on the sensing coil output signal.

Abstract: The invention is a device for measuring and surveillance of resistivity in a petroleum reservoir in a geological formation with an injection-, observation- or production well comprising an electrically conductive metallic well tubing, with the new and inventive being characterized by the following features: a) an electrical energy source; b) at least one inductive transmitter antenna for electromagnetic waves, fixedly arranged in the well, outside of the well tubing's outer metallic surface; c) at least one series of sensors comprising n inductive resistivity sensors (5a, 5b, . . . , 5n) arranged for receiving the electromagnetic waves and generation of measurement signals, fixedly arranged in the well, by the petroleum reservoir and outside the well tubing's outer metallic surface; and d) a signal conductor for the measurement signals.

Abstract: A stage system includes a movable stage, a first driving mechanism, having magnet and a coil unit, for moving the stage along a predetermined direction, the coil unit including a coil and a yoke, wherein the magnet is connected to the stage side, and a second driving mechanism for moving the coil unit along the predetermined direction. While a position or a speed of the stage is controlled as the stage is driven through the first driving mechanism, the coil unit is moved substantially in synchronism with the stage.

Abstract: A head testing apparatus is provided for testing a magnetic data recording head. The apparatus includes a test volume adapted to receive the magnetic data recording head and a magnetic field source positioned to generate a magnetic field within the test volume. A Hall sensor is positioned relative to the test volume and has bias current input terminals, voltage output terminals, an operating temperature and an impedance between the bias current input terminals, which varies with the operating temperature. A bias current source is electrically coupled to the bias current input terminals and is adapted to provide a bias current, which is modulated based on the impedance of the Hall sensor.

Abstract: An automated test system is provided for evaluating characteristics of photoreceptors used in the electrophotographic process. The test system includes a dielectric material support adapted to receive said dielectric material one or more electrodes adapted to apply electrical energy from a source to a two dimensional area adjacent the support for storage by the dielectric material and a sensor for the electrical energy stored in the dielectric material and providing an output representation of the dielectric relaxation of the material in response to the stored energy over the two dimensional area. This test system provides advantages over conventional Electrostatic Charge Decay (ECD) methods by eliminating corona pre-charging and a moving detector when a full-length array is used. Also, this test system utilizes a lower cost current detector in comparison to conventionally used voltage detectors.

Abstract: A signal scaling system and methodology for use in a signal measurement system such as a digital or analog oscilloscope, logic analyzer, network analyzer, spectrum analyzer or waveform generator that has a graphical user interface which controls a waveform display region on a display device. The signal scaling system determines one or more displayed waveform scaling parameters to cause portions of selected displayed waveforms appearing within a rescaling rectangle to occupy a predetermined portion of the waveform display region other than the resealing rectangle. For each of the selected displayed waveforms, the scaling parameters may include horizontal scaling, horizontal offset, vertical scaling and vertical offset. Preferably, the predetermined portion of the waveform display region comprises the entire waveform display region and the selected displayed waveforms include all waveforms at least partially within the resealing rectangle.

Abstract: Here is disclosed a MI element made of thin film magnetic material utilizing a magnetic impedance effect comprising a substrate, first and second magnetic materials successively laminated on a surface of the substrate each in the form of thin film wherein the first magnetic material has its axis of easy magnetization Jm1 declined at an angle of &agr;° and the second magnetic material has its axis of easy magnetization Jm2 declined at an angle of −&agr;° with respect to a reference line Oo which is a direction corresponding to a path of high frequency current Iac so that the axes of easy magnetization of the first and second magnetic materials may intersect each other. Such MI element made of thin film magnetic material obtains linear magnetic field sensor characteristics exhibiting a remarkably large variation of impedance in response to a relatively low external magnetic field without any demand for bias magnetic field.

Abstract: A displacement transducer is described, wherein an absolute value of the displacement of a mechanical component or a displacement change can be detected and a corresponding electric output signal can be generated. The mechanical component (2) is connected with a magnetizable tape (8, 8′, 8″), which can be moved in the longitudinal direction past at least one detection device (13, 14). The tape (8, 8′, 8″) is magnetized in predetermined sections (11) with respectively changing polarity, and the polarity changes are detected when the tape (8, 8′, 8″) moves in order to generate the electrical output signal.

Abstract: Eddy current sensor with an exploring coil (2) wound on a coil form (32), with two terminals (6, 7), a source of ac voltage, an electrically conductive measuring probe (3), and an evaluation circuit, wherein the measuring probe (3) is displaceable relative to the exploring coil (2), and the evaluation circuit generates an evaluation signal as a function of the position of the measuring probe (3), wherein the eddy current sensor comprises an electrode (4) with a tap (8) for enabling electrical contact, the electrode forming together with the windings of the exploring coil (2) and an intermediate layer (33) a component with distributed electromagnetic parameters, whose output signals are used to determine the position of the measuring probe (3).

Abstract: A magnetic incremental motion detection system 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 of the system is adjoined to an object to synchronously move with the object. A plurality of indications are adjoined to the target, and uniformly and serially disposed along an area of a surface of the target. The system further comprises one or more magnetic sensing devices spatially positioned from the area of the surface to define air gap areas therebetween. Each of the magnetic sensing devices are operable to output a digital signal in response to a synchronous movement of the target with the object. The outputted digital signals have the same duty cycle, and are consistently out of phase with each other by the same degree.

Abstract: A product sensor system for use in a refreshment center configured to sense a number of metal product containers. The sensor device can comprise a support shelf mounted in the refreshment center, which holds the product containers. One or more sensor loops are arranged on the shelf below the product containers, and an analysis circuit is connected to the sensor loops to measure the changes in inductance at the sensor loop when product containers are removed from the refreshment center. A microprocessor compares the signals from the inductance sensing circuit with values stored in memory to determine the amount of product remaining.

Abstract: The encoder of the present invention includes at least a pair of giant magnetoresistive effect elements, in which the giant magnetoresistive effect elements to be paired are formed on a substrate in a state that the elements are connected mutually electrically with the orientations of magnetization axes of the pinned magnetic layers each facing the same direction in parallel, a magnetic coding member is rotatably supported to face the giant magnetoresistive effect elements on the substrate, and the magnetic coding member has a plurality of magnetic poles formed along the direction of rotation of itself.

Abstract: A method and apparatus for determining properties of rocks surrounding a borehole in which electrokinetic signals are generated in the rocks is disclosed. For example, the signals may be generated by the vibration induced by the drilling of the borehole or by a seismic source emitting continuous pressure waves. The electrokinetic signals generated are detected and the signal amplified and processed to measure the porous rock properties.

Abstract: In a position detecting device for a moving object, such as a camshaft gear, having ridges and valleys, magnetoresistive elements are disposed in positions offset in the rotation direction of the moving object from the magnetic center of a bias magnetic field projected by a bias magnet. The direction of the bias magnetic field is different when the moving object is in a ridge position from when it is in a valley position. A mid-point potential of the MREs is taken as the output of an MRE bridge to obtain an output value which is different when the moving object is in the ridge position from when it is in the valley position. It is thus possible to distinguish between the ridge position and the valley position of the moving object.

Abstract: A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.