Abstract: A target wheel sensor assembly includes a target wheel, a magnet, and a sensing element placed therebetween. The magnet and the sensing element are configured so that as the target wheel rotates the sensing element outputs an asymmetric signal. This asymmetric signal is used to determine the position of the target wheel as it rotates and the direction of motion of the target wheel.

Abstract: The present invention provides an apparatus and method for measuring the resistivity of a sample of cement-based material. A transformer is formed with a primary coil, a secondary formed by means of a sample of said cement-based material, means for supplying a voltage to said primary, means for measuring the voltage induced in said sample, and means for measuring the current induced in said sample. The resistance of the sample can be measured and thus the resistivity of the concrete sample can be calculated.

Abstract: In an electronic caliper, a detecting circuit 112 detects displacement of a grid with respect to a scale, on the basis of a signal from a transducer 110. A CPU 114 displays the detected position on a display device 124. The CPU 114 performs error detection on the transducer, only when the relative speed of the grid with respect the scale is zero, or becomes equal to or smaller than a predetermined value. Since error detection is performed only at a predetermined timing, power consumption can be reduced.

Abstract: Metal detection apparatus wherein a transmit coil will transmit magnetic pulses, and the processing circuitry will weight a receive signal more heavily soon after a transmit pulse transition and less heavily after a longer period following the transmit pulse transition.

Abstract: Besides the measurement of angular position, an angular measurement system having an integrated Ferraris sensor also permits the direct measurement of angular acceleration or angular velocity. A graduated disk and an eddy-current disk are configured concentrically in one plane. Relief elements may ensure that temperature variations do not cause the connection between the graduated disk and the eddy-current disk to be lost.

Abstract: A system for locating underground or above ground metal and pipe objects includes a transmitter for generating an RF signal which is applied to the object which acts as a transmitter. An above-ground antenna array receives the RF signal transmitted by the underground object with a commutator for periodically and sequentially receiving signal from each antenna in the array, the commutator frequency modulating the received signal. A FM demodulator then demodulates the signal from the commutator and provides a Doppler effect frequency shift signal. A vector positional display then indicates position of the object based on the Doppler effect frequency shift signal relative to a reference signal.

Abstract: A vector positional display for use in an underground metal locating system for indicating the relative position of the underground metal with respect to a sensor array. The underground object functions as a RF transmitter, and the antenna array detects the transmitted signal. Commutation of the antenna array causes frequency modulation of the received signal which after demodulation can be used for identifying the direction of the object from the sensor array. A display slot counter accumulates count from a system clock, and resolution decoders determine field of view from the antenna array in locating the object. A zero crossing data probe triggers a display decoder which converts accumulated count to a format for energizing lights in the display unit.

Abstract: A new method and apparatus for detecting and measuring the level of metal present on the surface of a substrate is achieved. Energy, in the form of rf or light or microwave energy, is directed at the surface of a wafer, the reflected energy or the energy that passes through the semiconductor substrate is captured and analyzed for energy level and/or frequency content. Based on this analysis conclusions can be drawn regarding presence and type of metal on the surface of the wafer. Furthermore, by inclusion of metal within the resonating circuit of an rf generator changes the frequency of the vibration and therefore detects the presence of metal.

Abstract: An optical image separation system, connected to a confocal image output port of a Nipkow disk type confocal scanner, wherein light returned from a sample and emitted from the confocal image output port is separated into a plurality of different wavelen regions, respectively, so that a plurality of samples emitting different wavelenghts are concurrently detected.

Abstract: A shaft revolution counter including one or more reed magnetic sensors interacting with one or more magnets attached to the shaft. The interaction generates voltage spikes in the reed magnetic sensors that are used as input signal to an electronic non-volatile counter, as well as its sole power source.

Abstract: A housing for a proximity sensor is resistant to harsh environmental effects, such as scorching particles due to sputtering in a welding environment. The sensor housing is formed of a material having a high thermal conductivity, such as copper or an alloy thereof. As a result, the housing is able to rapidly dissipate heat and, in turn, mitigate weld slag build-up so as to improve the efficacy of the sensor.

Abstract: An inductive length measuring system which, by scanning a scale with a graduation of periodically variable reluctance and a coil system in a linear arrangement, can detect information relating to the position and/or the movement of the coil system with reference to the scale. The coil structure comprises a multi-ply arrangement of a combination of coils in the form of planar spiral windings or turns having a plurality of receiver pairs, each pair having two differentially connected receiver elements which can be interconnected for the purpose of signal generation for each of at least two measuring channels, and wherein at least one emitter element is provided which is inductively coupled to the receiver elements as a function of the relative position in the measuring direction relative to the measuring scale, thereby generating at least one output signal which is compensated for offset and/or sinusoidal shape and/or amplitude.

Abstract: An apparatus for measuring the magnetic field distribution of a magnetic sample includes a magnetic field sensor arrangement having three, orthogonally-disposed, Hall sensors for sensing the magnetic field produced by a magnetic sample at a given location, The sensor arrangement is scanned along a predetermined scan pattern. The apparatus then acquires sampling data from the sensor arrangement, the sampled data providing a representation of the magnetic field distribution of the magnetic sample. The data is preferably acquired by an interface card for a PC, which stores sampled data in the main memory of the PC for data analysis and display.

Abstract: A linear variable differential transformer (LVDT) assembly comprises a housing. A tube extends into the housing. An armature mounts inside of the tube and can move longitudinally within the tube. A coil assembly, which includes a primary coil and two secondary coils mounts on the outside of the tube. The coil assembly has adjustable connection with the housing. Consequently, the coil assembly can be adjusted longitudinally with respect to the armature until the LVDT is in the null position. That occurs when the differential voltage from alternating current through the secondary coils is zero.

Abstract: A magnetic flux detector comprises a core member 12 and an armature member 11, and the core member 12 generates a magnetic flux by an exciting coil 13 when the exciting coil receives an excitation current controlled by an excitation current controller 30. The magnetic flux detector further comprises a search coil 14, which is provided in a magnetic path for the magnetic flux, and a magnetic flux calculator 40, which determines the magnitude of the magnetic flux by measuring an electromotive force induced in the search coil 14 by a change in the magnetic flux. The magnetic flux calculator 40 has a potential setup resistor 43, whose resistance B is sufficiently larger than the internal resistance A of the search coil 14 (approximately A=B/3˜B/30).

Abstract: A device for reading an elongate magnetic data carrier attached to or embedded in an article, having an active read head adapted to have a lateral extent greater than the width of the data carrier, preferably four times greater, such that the magnetic field produced by the read head results in a signal from the data carrier which has an amplitude which varies by less than 50% for head to data carrier spacings of from 0 to 60 microns. A wide read head can also make the reading of data more reproducible when reading narrow tracks using swipe readers, where precise alignment is difficult to achieve.

Abstract: An apparatus for contact-less measuring a difference angle between two parts rotating about a common axis comprises an annular shaped stator having magnetic pole pairs on an inner circumference, and a cylindrically shaped ferromagnetic rotor having pole ends for magnetically scanning the pole pairs of the stator. There are a first air gap between the pole pairs of the stator and the pole ends of the rotor; and an accessible and rotationally symmetric second air gap between the inner circumference of the stator and the rotor. The magnetic flux across the second air gap is changed according to the difference angle between the rotor and the stator. This is determined by a magnetically sensitive element which is arranged at a fixed position within the second air gap.

Abstract: The present invention provides a highly sensitive TMR device. Since a TMR device is normally manufactured by a thin-film formation technique, the size and weight can be reduced. The thickness of a first spin polarization layer that is stacked on a soft magnetic layer for assisting magnetic field sensing operations and has a higher coercive force and a higher spin polarization rate than the soft magnetic layer is adjusted to a value that is smaller than the thickness of a tunneling layer or smaller than 2 nm, whichever is smaller. With the first spin polarization layer having such a thickness, both a low coercive force and a desirable TMR rate can be obtained. As a result, the magnetic field sensitivity of the TMR device as a sensor can be increased.

Abstract: A unique time-domain electromagnetic system and data processing technique which, using low frequency electromagnetic fields, can localize, in three-dimensions, the position of buried metallic objects is disclosed. The measurement system uses time-domain electromagnetic techniques on a scanning frame similar to a X-Y plotter. The system collects magnetic data over a large area above the buried object. The spatial information of the field detected on the ground is then processed with an unique ‘nearfield holographic’ data processing method to reconstruct the field image of the buried object.

Abstract: A magnetic-based sensor is disclosed which can detect a linear and rotary position of a shaft whose movement is to be measured. Such sensor can operate to yield linear displacement as well as rotation. A position magnet is mounted on the shaft for measuring linear motion. A spirally wound magnet is mounted on the shaft to detect rotational motion. Both of such motions are detected by a single magnetic-based sensor.