Abstract: Metal detection apparatus containing at least two inductive coils one of which acts as a transmit coil and all of which act as receive coils and processing circuitry wherein a proportion of the first receive electronic signal and a proportion of the second receive electronic signal may be selected to produce various first resultant linear combination signals for the purpose of improved interference cancelling.

Abstract: A fluxgate micro-magnetometer with perpendicular detection and a process of realization thereof. A ferromagnetic core is perpendicular to a substrate. The axes of excitation coils and pick-up coils are also perpendicular to the substrate. A magnetic field component which is perpendicular to the substrate is thus measured. The two other components can be measured by magnetometers of classical type whose core is parallel to the substrate. Such a device may find application in the domain of magnetic measurement, as an example.

Abstract: A metal detector apparatus including a transmit coil which transmits a magnetic field, transmit timing control circuitry which also includes timing for a semiconductor switch, and receive signal circuitry and receive signal processing circuitry, with a transmit coil damping network including at least one resistor connected in series with the semiconductor switch across the transmit coil, and timing control circuitry which generates a timing sequence which is selected so that for at least some of the time no transmit field is generated and at least during part of the transmit signal, the first semiconductor switch is controlled to be off and is turned on before the cessation of the transmit field.

Abstract: An electro-optic sampling apparatus is provided to enable measurement on potentials of signals on the conductor of coaxial cable with high precision and with ease. Herein, an electric input connector inputs a measured electric signal, which is introduced to a conductive path such as a microstrip line. An electro-optic material (e.g., Bi12SiO20) that provides electro-optic effect such as Pockel's effect is fixed to a bare portion of the conductive path and is varied in birefringence ratio in response to strength of electric field caused by the conductive path through which the measured electric signal transmits. The conductive path is then terminated by a terminal device. Now, a laser beam is radiated toward the electro-optic material, wherein it is varied in polarization in response to variations of the birefringence ratio. Then, the laser beam is reflected by a dielectric mirror and is separated into two beams by a polarization beam splitter.

Abstract: A method of determining a magnetic track width of a magnetic head. The method begins by obtaining a full track profile of the magnetic head which includes a plurality of signal amplitudes read across a track of a magnetic disk at a plurality of magnetic head positions. An initial magnetic track width value is then determined from the full track profile data. Preferably, this initial value is the magnetic write width which is determined based on the difference between left and right head positions which read half of the maximum signal amplitude. To determine the final magnetic write width, the initial value is adjusted with side reading correction values. The side reading correction values are determined based on left and right side reading “tails” of a bell-shaped signal curve which is formed by the full track profile data when graphed. It is not necessary to obtain the microtrack profile to determine these side reading values.

Abstract: A rotation sensor provided with a first rotor fixed to a shaft, a second rotor fixed to the same or other shaft and adjoining the first rotor, and a core having a resonance coil, arranged around the first rotor, and which coil forms a magnetic circuit working with the first rotor. The first rotor is formed of a magnetic material comprising an insulator; an irregular magnetic field is formed with the core; and the second rotor is provided with a conductor cutting across areas of different intensities of the irregular magnetic field in accordance with the difference of the angle of rotation when a difference in the angle of relative rotation occurs at a shaft position where the first rotor is fixed and at a shaft position where the second rotor is fixed.

Abstract: The invention relates to a device with a magnetic position sensor comprising a field sensor (5) and analysis electronics (7) for linear displacements of a rod-shaped component (3), in particular the shaft of an actuator, with an element (M) generating a magnetic field (4) and a position sensor measuring the magnetic field strength angle of this field, the field angle signal determined by this sensor being used for displacement path determination. The element generating a magnetic field (4) is an axially magnetized magnet casing (M) which surrounds the rod-shaped component (3) of the actuator itself, is fixedly connected thereto and can rotate therewith about its displacement axis (z).

Abstract: A displacement sensor for providing an indication of the position of a first body relative to a second body, the first body being displaceable relative to the second body in a displacement direction. The sensor is composed of: two magnets that are spaced from one another in the displacement direction to define therebetween a region containing a magnetic field; a magnetic field sensing element mounted in the region; and components for coupling at least one of the magnets to one of the bodies and the magnetic field sensing element to the other of the bodies to produce a relative displacement between the at least one magnet and the magnetic field sensing element in the displacement direction in response to displacement of the first body relative to the second body.

Abstract: A magnetic sensing transducer device that senses low frequency magnetic fields by using flux concentrators that modulate the observed low frequency signal, thereby shifting this observed signal to higher frequencies and minimizing 1/f-type noise. This is accomplished by the oscillatory motion of a microelectromechanical (MEMS)-type magnetic flux concentrator operated with a magnetic sensor, preferably made on a common substrate. Such a combined device can be used in a magnetometer. Such a device is small, low-cost and has low-power-consumption requirements. The magnetic sensor can be a Hall effect or other type of magnetic sensor. At least one MEMS-type fabricated flux concentrator is used with the magnetic sensor. The concentrator oscillates at a modulation frequency much greater than the observed magnetic field being sensed by the device.

Abstract: An invention is disclosed for an optical endpoint detection system that utilizes optical interference to determine when a metal layer has reached a thin metal zone during a CMP process. A portion of a surface of a wafer is illuminated with broad baned light source. Then, reflected spectrum data corresponding to a plurality of spectrums of light reflected from the illuminated portion of the surface of the wafer is received. An endpoint is then determined based on optical interference occurring in the reflected spectrum data, which is a result of phase differences in light reflected from different layers of the wafer, and occurs when the top metal layer is reduced to the thin metal zone.

Abstract: A system for measuring the magnetostriction coefficient &lgr; of a sample material applied to a substrate element fixed at one end leaving the other end free to be deflected. An external rotating magnetic field of rotation frequency f and intensity Hext is applied to the cantilever substrate element the amplitude Am of the deflection of the free end is measured at each of a plurality of rotation frequency harmonics {fm} by, for example, using a plurality of lock-in amplifiers. The harmonic deflection amplitudes {Am} are combined to determine the magnetostriction coefficient &lgr; of the sample material. At an Hext equal to the sample saturation moment Msat and assuming a 15 Oe sample anisotropy Hk and coupling bias Hp, the error in the saturation magnetostriction coefficient &lgr;S measured according to this invention may be reduced by 80% to 90% over the error seen when using only the second harmonic deflection amplitudes A2.

Abstract: A method for seismic exploration using nonlinear conversions between electromagnetic and seismic energy, with particular attention to the electromagnetic source waveform used. According to the invention, seismic returns from a source waveform are correlated with a reference waveform, with both waveforms custom designed to minimize both correlation side lobes and interference from linear electroseismic effects. A waveform element is selected which may be sequenced by a binary or similar digital code embodying the desired custom design to generate an input sweep with the needed depth penetration and noise suppression. Correlation of the seismic response with the reference waveform in a data processing step mathematically aggregates the seismic response from the input sweep into a single wavelet. Preferred binary digital codes include prescribed variations of maximal length shift-register sequences. Also, an apparatus for generating the desired waveforms.

Abstract: A magnetic head wear-rate measuring apparatus for measuring the rate of head wear in noncontact form arranged to be opposed to a magnetic head and to serve as a part of oscillating elements of an oscillator circuit. A magnetic resistance of a magnetic circuit at a rotational position where the magnetic head faces the magnetic sensor, changes according to the degree of extension of the magnetic head from the surface of the drum, and the change in magnetic resistance acts as a variation in oscillating frequency. A counter is supplied with a pulse of a measured oscillating frequency and produces a pulse having a pulse width up to the counting of a predetermined number of pulses. The counter output is supplied to a second counter where the number of reference clocks lying within the pulse width is counted and used as measured data.

Abstract: Inductive sensors measure the near surface properties of conducting magnetic materials. The sensors generally include parallel winding segments to induce a spatially periodic magnetic field in a material under test. The sensors may provide a directionally dependent measure with measurements made in varying orientations of the sensor with respect to the material property variation directions. The sensors may be thin, conformable sensors that can be mounted on a test material and, for example, monitor crack initiation under the sensor. A second sensor may be left in air to provide a reference measurement, or the temperature of the material under test can be varied to verify the response of the individual sensing elements. Sensors can be mounted to materials under test in order to not modify the environment that is causing the stress being monitored.

Abstract: For reducing the number of components used and thereby attaining the reduction of cost and size while ensuring the same disk detecting performance as in the prior art, both light emitting function and light receiving function inherent in an optical pickup are utilized to constitute a disk detecting switch. Only the light emitting function of the optical pickup may be combined with a light receiving element, or only the light receiving function of the optical pickup may be combined with a light emitting element, to constitute a disk detecting switch.

Abstract: A metal detector with a transmit coil which transmits a magnetic field, transmit timing control circuitry, and receive signal circuitry and receive signal processing circuitry, and a low voltage and a high voltage power supply. The timing sequence generated within the transmit timing control circuitry produces control signals such that there are at least two different transmit periods, a short and a long period, and such that there are periods when no current flows through the transmit coil. The timing sequence is such that an average transmit coil energy at termination of the long periods is similar to that of an average transmit coil energy at termination of the short periods.

Abstract: A system includes a boring tool that is moved through the ground while transmitting a dipole locating signal such that the locating signal exhibits a pair of locate points at the surface of the ground. A local flux intensity of the locating signal is measured for at least one above ground point using a portable locator. A horizontal flux vector is established at that point, which is generally oriented in a horizontal plane, by using the measured local flux intensity to determine components of the locating signal in the horizontal plane that define the horizontal flux vector. The locator is moved in a direction generally defined by the orientation of the horizontal flux vector as at least an intermediate step in establishing the position of the nearest locate point. After moving, the procedure may be repeated to progressively converge on the nearest locate point.

Abstract: A magnetic flux detector has a core member and an armature member. The core member generates a magnetic flux by an exciting coil receiving an excitation current controlled by an excitation current controller. The magnetic flux detector also has a search coil provided in a magnetic path for the magnetic flux, and a magnetic flux calculator, which determines the magnitude of the magnetic flux by measuring an electromotive force induced in the search coil by a change in the magnetic flux. The excitation current controller controls the excitation current to increase from zero to a predetermined value during a first predetermined time period and then to decrease to zero during a second predetermined time period. The magnetic flux calculator determines the magnitude of the magnetic flux based on the integrated electromotive forces during the first and second time periods.

Abstract: The support that bears and positions the head in a head holding apparatus is further supported by a heat-compensating member, so that when the support is expanded by the heat source of the head holding apparatus, the heat-compensating member expands in the direction opposite to the direction of expansion of the support. Moreover, supplying of heat to the support and heat-compensating member is further alleviated by insulating said heat source with an insulating material. The amount of displacement of the recording element per unit of time with exposure to heat is controlled by the above-mentioned structure and effects.

Abstract: A differential pulse transformer having a drive coil (10a) and differential sense coils (10b) are disposed on a planar surface with a target (10e, 10f) movable over the sense coils to cause an imbalance in magnetic field when a large di/dt pulse is generated in the drive coil. A detection circuit senses the imbalance and provides a digital output accurately identifying the position of the target. Coil and target embodiments include relatively small secondary coils and relatively long targets (10b, 10e/10f; 12b, 12e/12f and 14b) and relatively large secondary coils and short targets (16b, 16c; 18b, 18c; 20b and 22b).