Abstract: A magnetic encoder includes a magnetic drum having, on the outer peripheral surface thereof, magnetized portions spaced at equal pitches; a magnetic sensor unit opposed to the outer peripheral surface of the magnetic drum; magnetic sensors are provided in the magnetic sensor unit spaced at a distance smaller than one pitch of the magnetized portions; a calculation device for calculating two sets of vectorial signals, from detection-signal output levels of the magnetic sensors generated upon rotation of the magnetic drum or the magnetic sensor unit, using the following equations (1) and (2): Aout=&Sgr;Wm=1Vm×sin &thgr;m  (1); and Bout=&Sgr;Wm=1Vm×cos &thgr;m  (2); wherein W designates the number of the magnetic sensors; Vm designates the detection-signal output levels of the magnetic sensors generated upon rotation of the magnetic drum or the magnetic sensor unit; Aout and Bout designates one and another set of vectorial signals.

Abstract: An encoder unit is disposed facing a scale. The encoder unit is constructed such that a processing circuit and a read head are integrally formed on one and the same semiconductor substrate. This construction results in size reduction and integral formation of the encoder unit.

Abstract: A method and apparatus for measuring changes in the media within a geologic formation by transmitting magnetic flux through a section of ferromagnetic well casing and measuring the change in flux received back through the casing. The flux transmitter and receiving components may be permanently installed in a hydrocarbon production well.

Abstract: A position sensor for determining a set position thereof is disclosed. The sensor comprises a time-varying magnetic field generator. A movable electrically conductive element is positioned such that the time-varying magnetic field generates eddy currents therein. At least one pick-up is provided for generating a signal in response to the time-varying magnetic field. Movement of the conductive element relative to the pick-up alters the magnetic coupling between the magnetic field generator and the pick-up allowing the set position to be determined unambiguously.

Abstract: A position sensor module in which a position sensor delivers a signal output to an electronic evaluation unit for further processing, wherein the sensor module and evaluation unit are mounted on and electrically connected by a shaped sheet metal part to eliminate the need for tuning adjustments between the position sensor and the electronic evaluation unit.

Abstract: Measuring the wall thickness of an electrically conductive object using a probe comprising a transmitter coil, a first receiver and a second receiver, which method comprises arranging the probe near the object; inducing transient eddy currents in the object and recording the signals of the receivers with time; measuring the wall thickness from a characteristic of one of the signals; calculating a characteristic value from a combination of the signals; and correcting the measured wall thickness for the distance between the probe and the object using a pre-determined relationship between the wall thickness and the characteristic value for different values of the distance between the probe and the object.

Abstract: An optical apparatus and methods for efficiently determining the magnetization of a material at very high optical resolution are disclosed. Individual components of the magnetization may be determined. Components in the plane of the sample surface are imaged by illuminating the material obliquely with substantially parallel light of relatively high power and very well controlled uniformity and polarization, and using light scattered obliquely in a parallel beam in the opposite direction at the same angle as the angle of incidence to record an image. Reversing the illumination and observation directions allows subtraction of the two images and measurement of the magnetization in-plane. A second in-plane component orthogonal to the first, is obtained similarly after reorienting the plane of incidence 90 degrees.

Abstract: A magnetic sensor comprises at least one first coil and at least one magnetic sensing element, operatively connected to respective first and second locations of a body of a vehicle and to a ferromagnetic element of the body. The first and second locations are distinct from one another and are in magnetic communication through a first portion of the vehicle, wherein the first portion of the vehicle comprises a portion of the body that is susceptible to deformation by a crash. A sinusoidal signal comprising a plurality of frequencies is applied to the at least one first coil, and the at least one magnetic sensing element generates a second signal responsive thereto, from which a magnetic disturbance is localized or a crash is discriminated.

Abstract: A magnetic sensor comprises at least one first coil at an associated at least one first location of a body of a vehicle and operatively connected to a ferromagnetic element of the body. A signal comprising a leading edge is applied to the at least one first coil, and a second signal is sensed from the at least one first coil, wherein said second signal is responsive to the interaction of the first signal and the ferromagnetic element, and a magnetic disturbance is localized or a crash is discriminated responsive to the second signal.

Abstract: A linear position sensor assembly includes a moving target and a stationary magnet. A magnetic sensor is placed adjacent to the magnet and senses changes in the magnetic flux density caused by the target moving within a magnetic field generated by the stationary magnet. The magnetic sensor outputs a signal that is linear over nearly the entire length of the target.

Abstract: A position sensor including at least one stator structure defining a secondary gap wherein is housed at least one Hall probe, and a mobile magnet in a main gap. The stator structure includes stator parts defining at least one first secondary gap wherein is housed at least one first Hall probe delivering a signal which is a function of the displacement of the mobile magnet relative to a first degree of freedom, and at least one second secondary gap wherein is housed at least one second Hall probe delivering a signal which is a function of the displacement of the mobile magnet relative to a second degree of freedom.

Abstract: A dc connection (CAB1, CAB2) in a bipolar 12-pulse system for transmission of electrical energy by means of high-voltage direct current interconnects two converters, each one having two 6-pulse valve bridges (BR11, BR12, BR21, BR22) connected in series at a connection point (J1, J2). In a method for location of the cable, said cable is located by sensing of a magnetic field associated with a current flowing through the cable. The dc connection is temporarily supplied with a ground-mode current, intended for the location, and a magnetic field associated with said ground-mode current is sensed.

Abstract: A method of calculating an amplitude decay rate of a magnetic storage medium. The method involves (a) writing a test track to the magnetic storage medium and measuring the initial amplitude of the test track to obtain a reference amplitude; (b) performing a DC erase on the test track; (c) measuring and storing the test track amplitude after step (b) together with a time at which the measurement was made; (d) writing a reference track; (e) measuring and storing the reference track amplitude after step (d); (f) repeating steps (b) to (e) until a DC erase amplitude decay rate has been established; and (g) calculating a normal amplitude decay rate for the magnetic storage medium from the DC erase amplitude decay rate.

Abstract: A non-linear Hall IC that stores conversion information for converting Hall voltage output from a Hall element, and converts the Hall voltage into an output voltage based on the conversion information stored. The Hall voltage is converted into the output voltage such that a relation between the magnetic field strength and the output voltage becomes a non-linear relation.

Abstract: A method of inspecting an electrically conductive object so as to detect the presence of an anomaly using a probe comprising a transmitter coil and a receiver coil, which method comprises the steps of: (a) selecting a set of points on the near surface of the object that are to be inspected; (b) selecting a first inspection point from the set; (c) positioning the probe at the selected inspection point, inducing eddy currents in the object and determining a characteristic value, &PHgr;, of the electromagnetic field generated by the eddy currents; (d) selecting a next inspection point from the set and repeating step (c) until all inspection points have had their turn; and (e) inferring that an anomaly is present at an inspection point if the characteristic value &PHgr; differs significantly from a norm.

Abstract: A position detector comprising a sensor head and rod is formed to have an arc-like configuration along a rotation locus of a rotating body and an amount of movement of the sensor head along the rod is converted to an angle by dividing the movement amount by a curvature radius common between the rod and the sensor head. By doing so, the rotation angle of the rotating body is calculated.

Abstract: The invention relates to a process for testing of a workpiece by means of eddy currents induced by a field coil in the workpiece and from which a measurement signal is obtained by means of a measurement sensor, a pattern signal representative of a workpiece fault being generated, a correlation function of the measurement signal acquired by the sensor with the pattern signal being determined, and the correlation function being evaluated in order to detect a fault in the workpiece. The invention furthermore relates to a device for executing the process.

Abstract: A thickness measuring system comprises: an eddy current loss measuring sensor having an exciting coil for receiving a high frequency current to excite a high frequency magnetic field to excite an eddy current in a conductive film, and a receiving coil for outputting the high frequency current which is influenced by an eddy current loss caused by the eddy current; an impedance analyzer for measuring the variation in impedance of the eddy current loss measuring sensor, the variation in current value of the high frequency current or the variation in phase of the high frequency current on the basis of the high frequency current outputted from the receiving coil; an optical displacement sensor for measuring the distance between the conductive film and the eddy current loss measuring sensor; and a control computer including a thickness calculating part for calculating the thickness of the conductive film on the basis of various measured results of the impedance analyzer and optical displacement sensor, and the eddy

Abstract: A minimal magnetic-field measurement Dewar vessel includes an inner container which contains a superconducting device and cooling medium, a radiation shield which is composed of an electrical insulation substrate and a first and second plurality of thin line stripes provided on opposite surfaces of the electrical insulation substrate so that the first plurality of thin line stripes is electrically insulated from the second plurality of thin line stripes and provided in a high stripe dense state, an outer container, and a cooling apparatus. A width of one portion of at least one of the first and second plurality of thin line stripes arranged in one area of the radiation shield surrounding the superconducting device is smaller than a width of another portion of the at least one of the first and second plurality of thin line stripes arranged in another area of the radiation shield, respectively.

Abstract: A method and apparatus for non-destructively measuring the depth of a crack with precision and accuracy in a workpiece using an eddy current process. The method involves empirically creating a response curve of the eddy current response produced from crack(s) in a sample workpiece(s), wherein the depth of the crack(s) in the sample workpiece(s) may be modified a plurality of times and an eddy current response reading is taken at each different crack depth. The response curve is then used to interpolate the depth of a crack in a workpiece composed of the same material non-destructively by measuring the eddy current response in the workpiece crack and then obtaining the predetermined crack depth value form the response curve.