Abstract: A cancellation circuit provides active electromagnetic shielding for canceling inductive noise in electrical circuits caused by electromagnetic flux. The cancellation circuit includes amplitude-adjustment and phase-adjustment circuits for adjusting the amplitude and phase of electrical signals, and a combining circuit for combining electrical signals such that the effects of electromagnetic induction cancel. An electromagnetic pickup is provided with a cancellation circuit for canceling its response to electromagnetic flux. An electromagnetic drive coil is provided with a cancellation circuit for canceling electromagnetic flux in a predetermined region of space, and a compensation circuit compensates for frequency-dependent phase and amplitude variations in electrical pickup signals and transmitted electromagnetic flux. The cancellation and compensation circuits may be combined to provide a device that can simultaneously transmit and receive electromagnetic radiation.

Abstract: An electrical discharge lamp device in which an ultraviolet filtering globe tightly encloses a sealed glass bulb of an arc tube containing a pair of oppositely disposed electrodes to thereby form a unitary body. The rear end part of the arc tube extending from the ultraviolet filtering globe is supported by an insulating base, and the forward end part of the arc tube is supported by a lead support extending forward from the insulating base. An extending part is formed on the front face of a base main body made of synthetic resin, and the rear part of the ultraviolet filtering globe is supported by the tubular extending part. In this construction, stress is not concentrated on the portion of the arc tube supported by the base main body of the arc tube, and hence the durability of the arc tube is improved.

Abstract: A method and apparatus for detecting displacement of valve rod movement in electropneumatic position regulators, by generating a high-frequency electromagnetic alternating field by exciting a high-frequency oscillation within an LC oscillating circuit in an inductive sensor, damping the high-frequency oscillation as a function of displacement via an electrically conductive body moved along by the valve rod, demodulating the oscillator signal and feeding the demodulated signal to a microcomputer without amplification for evaluation of the displacement-dependent damping of the oscillation amplitude, measuring the temperature within the inductive sensor, correlating the temperature with the measured oscillation amplitude in the microcomputer, and determining a corrected displacement signal from the correlation.

Abstract: Processing methods and apparatus that process magnetometer data derived from an array of magnetometer sensors and outputs both the position and velocity of a magnetic dipole. In the method and apparatus, (a) a set of actual magnetic field measurements of a magnetic dipole is collected using the array of magnetic sensors. Then (b), a trajectory for the magnetic dipole is hypothesized. Then (c), a set of estimated magnetic field measurements is determined that would be formed by a magnetic dipole moving along the hypothesized trajectory. Then (d), the actual magnetic field measurements are compared with the estimated magnetic field measurements. Then (e), based on the comparison, a new trajectory for the magnetic dipole is hypothesized. Steps (c) through (e) are repeated until agreement between the actual magnetic field measurements and the estimated magnetic field measurements is deemed sufficiently close. The trajectory is displayed for viewing on a display.

Abstract: A compact fluorescent lamp is provided in a coiled or helical configuration in order to maximize the length of discharge tubing for a given height. A non-uniform coating of phosphor is provided on the interior surface of the discharge envelope to inhibit light otherwise directed inwardly into the lamp toward a longitudinal axis of the helical configuration and redirect the light outwardly through an outer circumferential portion having a thinner phosphor coating. This results in increased light output for an given lamp geometry and lamp power.

Abstract: A color-picture tube having a convergence electrode, to which a focusing voltage is applied, a final accelerating electrode, to which an anode voltage is applied, and at least one supplementary electrode placed between the convergence electrode and the final accelerating electrode, to which either (1) a voltage higher than the focusing voltage and lower than the anode voltage is applied or (2) no voltage is applied, resulting in the supplementary electrode being free from a directly applied electric potential, wherein its electric potential is induced by the convergence electrode and the final accelerating electrode. Each of the convergence electrode and the final accelerating electrode is a tube having an elliptical cross section closed with an elliptical end plate having three holes arranged in-line for electron passage. In at least one of the tubes, the end plate is positioned away from the opening of the tube closer to the supplementary electrode.

Abstract: The invention relates to a distribution device for distributing microwave power to excite a plasma inside an enclosure. According to the invention, the distribution device includes at least one second applicator of microwave energy to co-operate with a first applicator and an exciter to form at least one excitation triplet in which firstly the first applicator and the second applicator are mounted substantially parallel to each other and are spaced apart by a given amount to define between them a propagation zone for microwave energy, and secondly the exciter is disposed inside the enclosure by being placed relative to the first and second applicators in such a manner that the trajectories of the electrons do not cross the propagation zone, thereby dissociating the propagation zone and the absorption zone.

Abstract: Formation anisotropic properties are determined using knowledge of the borehole dip angle and an induction logging instrument to obtain two formation derived resistivities. Separate shale layer anisotropic properties are further determined utilizing the logging instrument in a like manner. A sand resistivity and a net/gross ratio may be derived from the formation and shale layer anisotropic information.

Abstract: The present invention relates to a method and to a device (1) for correcting measurement errors of a magnetometer (2) mounted on a vehicle (3). According to the invention:a theoretical corrective model [A].Hm+a.Hm'+Hp=[M].H is defined, in which [A], a and H are elements to be determined, Hm is the measured field, Hm' the time derivative of Hm, H the effective field and [M] a transformation matrix;a vector error E=[M].H-([A].Hm+a.Hm'+Hp) is defined;the square of the error thus defined is determined; andthe coefficients of the model which minimize the sum of the squares of the errors for all the measurements taken are identified.

Abstract: An EL lamp having a transparent front electrode is overprinted with an opaque graphic having the same color as the phosphor in the lamp. A translucent coating over the graphic is clear or tinted. The graphic is visible only when the lamp is lit. In an alternative embodiment of the invention, a second graphic, visible whether or not the lamp is lit, is overprinted on the lamp. The second graphic has a color perceptibly different from the color of the phosphor and is opaque, transparent, or any opacity between opaque and transparent.

Abstract: An underground utility conveyance (10) may be precisely located by impressing both a locating tone and a confirmation tone on the conveyance. The locating tone is an RF signal that produces a first field that radiates above the earth that is sensed by a first, above-ground signal detector (22) to establish the general location of the conveyance. The confirmation tone is a near-DC signal that produces a second, field having a relatively limited radiation path. A second detector (24) is inserted into the earth at successive places in the region where the conveyance is located to establish its precise location.

Abstract: In a two-channel magnetic metal detector having first and second mutually inductively coupled detection coils connected to first and second detection channels, respectively, the inductance of the coils is tested by applying a square wave test signal to the first detection coil and determining if the resulting output signal from the second detection channel has a magnitude falling within a range of magnitudes defined by two threshold values stored in a non-volatile memory. A microcomputer applies digital signals to a digital to analog converter to generate the square wave. The output signal from the second detection channel is repetitively sampled and digitized and the digital values are transferred to the microcomputer which includes means for comparing the digital values with the threshold values.

Abstract: The tachometer includes a microphone for disposition next to the exhaust of the vehicle and an accelerometer for disposition adjacent to its engine. A selected one of the outputs is connected to an ADC which provides digital samples to a central processing unit. Also, the ripple from the battery is sampled and provided to the CPU. The CPU calculates a constant representing the relationship of the frequencies of the ripple samples and the mechanical samples and responds to the ripple samples and the constant to provide output signals corresponding to the speed of the engine. The speed is displayed.

Abstract: A displacement detector detects a relative position between a wire rope and a pulley of a transfer apparatus. The detector includes a magnet disposed to face the wire rope, two magnetoelectric conversion units disposed relative to a pitch of lays of the wire rope to produce two output voltages having ripple components caused by the pitch of lays and being opposite to each other in terms of phase, and a circuit unit connected to the magnetoelectric conversion units for detecting displacement degrees of the wire rope from the pulley according to the output voltages and adding the output voltages so that said ripple components of opposite phases offset each other thereby removing effects of said pitch of lays.

Abstract: A metal detector comprise a coiled conductor located within a metal enclosure operative to provide an a.c. generated primary electromagnetic field. Metal screening is provided adjacent the coil so as to provide a secondary induced magnetic field which opposes the primary electromagnetic field so as to significantly reduce the metal free zone.

Abstract: An electromotive induction current which is detected by an induction coil placed in an electromagnetic field generated by applying an alternating current to an exciting coil distinctively changes with the frequency of the applied alternating current in accordance with the conditions of an object placed in the electromagnetic field. By analyzing the change in amplitude and/or frequency phase of the electromotive induction current, the physical properties, size and relative position of the object and internal defects such as a crack and pin hole in the object can be measured precisely.

Abstract: A magnetic detector includes a magnetizer generating a magnetic field; a first magnetic sensor for detecting a leakage flux resulting from a magnetically defective portion of an object moving in and relative to the magnetic field; a low-pass filter for extracting a low-frequency signal component contained in the signal output by the magnetic sensor, the low-frequency signal component being indicative of a floating flux which crosses the magnetic sensor and is a result of the object moving through the magnetic field; an amplifier for amplifying the extracted low-frequency signal component; a compensating coil excited by the amplified low-frequency signal component output by the amplifier, for generating a magnetic flux which cancels out the floating flux crossing the magnetic sensor; a high-pass filter for extracting a signal resulting from the magnetically defective portion and contained in the signal that is output by the first magnetic sensor; an output amplifier for amplifying a signal output by the high-p

Abstract: At least one transmitting coil 1 and at least one receiving coil 2 are disposed along the bore axis 18 of a borehole 7 such that these coils are inclined and face each other, thus causing these coils to have directivity for examining electric characteristics of a formation around the borehole. More specifically, a method of and an apparatus for directional induction logging are provided, which permit measurement of the electric conductivity distribution of a formation in the circumferential direction in a range of several meters around the borehole and also imaging reflecting the electric conductivity.

Abstract: A method and system for driving an air core gauge whereby pointer resolution of an air core gauge is improved across a full range of motion. The method including the steps of generating a first gauge control signal responsive to a signal, the first gauge control signal having a first duty cycle corresponding to a first pointer position; generating a second gauge control signal responsive to the signal, the second gauge control signal having a second duty cycle corresponding to a second pointer position; and modulating between the first gauge control signal and the second gauge control signal alternating drive periods to drive the gauge pointer to display an average pointer position.

Abstract: A superconducting magnetic sensor includes a SQUID for interlinking with an external magnetic flux, an A.C. bias circuit for driving the SQUID with an A.C. bias current having a first frequency, a feedback circuit supplied with output voltage pulses from the SQUID for calculating a difference between the total number of positive output voltage pulses and the total number of negative output voltage pulses and for producing a feedback magnetic flux in response thereto such that the external magnetic flux is canceled out by the feedback magnetic flux, and a modulation current source for supplying a modulation current having a frequency substantially smaller than the frequency of the bias current and for producing a modulation magnetic flux in response to the modulation current such that the modulation magnetic flux interlinks with the SQUID.