Abstract: An inductive transducer for measuring rotary displacement is provided in which the transducer uses a probe capable of being displaced within a hollow interior portion of a partially toroidal coil. The partially toroidal coil, which is typically uniformally wound, is connected in parallel with a stable-frequency current-based oscillator which transmits an AC voltage oscillating signal relating to the inductance of the coil. A demodulating circuit, which is capable of converting the AC voltage oscillating signal to a DC voltage level, is connected in parallel with the oscillator. In one preferred embodiment, the probe is inserted into the hollow interior portion of the partially toroidal coil by way of a pivoting arrangement. In operation, the probe is displaced within the hollow interior portion of the coil such that a change in inductance of the coil results.

Abstract: A cylindrical core sample of a subterranean formation is place into a sleeve under confining pressure. At least one electrode array extends through the sleeve and makes contact with the core sample. The array is in a plane normal to the core sample and has an even number of electrodes equally spaced about the sleeve. A current is passed through the core sample and voltages are measured across each pair of electrodes that are spaced 180.degree. apart around the sleeve. Such measurements are utilized to identify the radial direction of any electrical anisotropy in the core sample, particularly under differing fluid saturation conditions.

Abstract: A wide-band programmable tachometer and speedometer/odometer apparatus to detect the rotational speed of an output shaft of an engine in a vehicle and calculate the corresponding speed/mileage thereof. First, a converting device converts a mechanical motion of an engine into an electrical signal. Second, the electrical signal is amplified by two amplifiers and outputted as an amplified signal. Third, the amplified signal is sent to a frequency divider and then through a multiplexer. A selecting device is incorporated with the multiplexer to send out a signal with frequency in an operable range. An F-V converter is used to convert the signal from the multiplexer and to output a first, a second, and a third DC voltage. The second and the third DC voltages are used to drive a tachometer to display the rpm of an engine. The third DC voltage is sent to a V-F converter and through a monostable circuit unit and outputted as positive pulses.

Abstract: An adaptive revolution-measuring apparatus which includes a magnetic revolution sensor and an apparatus for comparing and evaluating the sensor signal of the revolution sensor to generate a digital output signal (U.sub.A) corresponding thereto, which despite large offset voltage tolerances and shifts uniquely identifies and evaluates the periodic sensor signal. The measuring apparatus contains a window comparator (17) with a controllable window as the apparatus for comparing which via at least one logic switching element (20, 21) drives a flip-flop (25) to produce the output signal (U.sub.A). Further apparatus are provided downstream of the window comparator which continuously generate corresponding reference voltages (U.sub.R1, U.sub.R2) for the window comparator as a function of the raised or lowered values of the sensor signal.

Abstract: A shock proof electrical probe comprises a probe tip, a casing for housing batteries, and a cap, each formed entirely of an electrically nonconductive plastic material. To establish an energizing circuit for the probe, the interior of the casing is provided with an elongated electrically conductive strip which extends longitudinally from contact with a circuit board in the probe tip, to an opposite open end of the casing, where the strip is mounted to the casing so as to bendable into electrical contact with an adjacent battery pole, and bendable in opposite direction to permit selective insertion and removal of the batteries from the casing. The probe further includes a steel carrying clip which is entirely encapsulated in electrically nonconductive plastic material. The probe may be of a noncontacting type, which utilizes an antenna for detecting the presence of an AC voltage, or a contacting type for detecting a the presence of a DC voltage.

Abstract: A method for operating a computer to control the manufacture process of zirconium tubes in a pilger mill operation, the computer including an electronic memory and being coupled to the pilger mill to receive, as input, data related to the operation of the mill. The method comprising, in one embodiment, the steps of storing in the computer memory respective test signals, each test signal corresponding to a signal obtained by inspecting a tube manufactured by the mill with a respective, known defective operation condition, inspecting a zirconium tube finished by the manufacture process and generating a signal representative of the physical dimensions and material configuration of the tube, comparing the generated representative signal of the zirconium tube with the stored test signals, alerting an operator if the generated representative signal of the zirconium tube correlates to a stored test signal, and identifying the defective operation condition which corresponds to the correlated stored test signal.

Abstract: A circuit for determining the speed of rotation of a wheel, has an inductive transmitter (1), the output of which is connected to a pulse-shaping device (7) whose output is connected to an evaluation device. The inductive transmitter is connected to an evaluation circuit (11) by means of a cable (6). The evaluation circuit is intended, on the one hand, to make certain that the input signal of the inductive transmitter (1) can be evaluated while, on the other hand, it should be able to detect errors which may occur, for instance due to a break in the cable (6) despite the presence of dirt resistances (R.sub.S). For this purpose, an auxiliary circuit (10) is provided which varies the internal resistance of the pulse-shaping device (7) as a function of the speed.

Abstract: Method of determining the rotational speed of a machine having a drive into which a setpoint value for the rotational speed has been introduced and a rotational-speed sensor from which a measured actual value is obtainable, which comprises feeding the setpoint value to a mathematical model of a controlled system formed by the drive and the machine, deriving from the output of the mathematical model a computed actual value, determining the difference between the measured actual value and the computed actual value, forming the absolute value of the difference, and, if the absolute amount of the difference is exceeded, passing on the computed actual value, and if the absolute amount of the difference is not exceeded, passing on the measured actual value; and device for performing the method as the determined rotational speed of the machine.

Abstract: A method of suppressing current distribution noise in a DC SQUID comprising two Josephson junctions (12) in a superconducting current. This current distribution noise is caused by individual fluctuations of the critical currents of the two Josephson junctions used for measuring weak magnetic fields. A DC SQUID is connected to a device which comprises a control device (14) for generating a periodic bias current (I.sub.b), a modulation device (15) for generating a flux modulation via an induced AC current in the loop (11), and a signal detection device (17) for forming a mean output voltage (V.sub.ges). The polarity of the bias current (I.sub.B) is reversed by the control device (14) with the modulation frequency and a time shift of one quarter of the period duration of the modulation frequency, so that the SQUID assumes different bias states.

Abstract: The control method/system for sensing "tooth or pulse drop-out" type faults in the output signals from a rotational speed sensor assembly (10) of the type utilizing a rotor (12) and a relatively fixed sensor (16) to provide an output comprising a plurality of pulses having a frequency indicative of the rotational speed of the rotor is provided.

Abstract: A cylindrical core sample of a subterranean formation is fluid saturated and subjected to a confining pressure. Voltages are measured in a plurality of directions through the core sample which are normal to the cylindrical axis of the core sample at a plurality of spaced-apart positions along such axis and utilized to determine resistivities. These resistivities are compared to identify the radial direction of any electrical anisotropy in the core sample for differing fluid saturation conditions.

Abstract: In a multi-channel SQUID fluxmeter for detecting magnetic flux signals by use of an array of SQUID flux sensors each comprising a digital SQUID for providing a pulse output, multiplexers and the like are appropriately used to allow pulse signals output from the SQUID flux sensors to be switched on a time series basis in order to obtain a magnetic flux signal for each channel. Thus, only one processing circuit need to be provided for a large number of SQUID flux sensors, thus reducing the scale of the fluxmeter and making the device small.

Abstract: The method and apparatus relies on a modified induction approach and preferably is incorporated into a metal drill collar for MWD measurements. Directional nulls are created in a primary changing magnetic field formed in a formation by a transmitting antenna which is in a groove on the surface of the drilling collar. Detecting antennas are placed at the directional nulls to enable the primary magnetic field to be decoupled from the same and allow it to be distinguished from the secondary field caused by the current induced in the formation by such primary field. The drill collar also carries a plurality of current detectors which detect the value of current induced in the formation to provide a resistivity profile immediately adjacent the borehole. A preferred embodiment uses a hybrid modified induction and electrical approach.

Abstract: In a measurement device for contactless determination of the rotation angle and/or rotation speed, a disk is fastened on a shaft so as to be fixed with respect to rotation relative to it. During the measurement process, layers of material with good electrical conductivity which are arranged on one or both opposing sides of the disk are moved relative to receiver coils located on opposite sides of the disk (16a and 16b). The measurement device can work according to the eddy current measurement method, as well as according to the inductive method. In order to compensate for measurement errors, the conductive layers are arranged at approximately equal distances (a, b) between two coils. In addition, the greatest possible quantity of measurement points can be used for forming an average.

Abstract: A well logging apparatus and method for measuring the resistivity of the formation surrounding a borehole is disclosed. The invention provides two transmitting antennas arranged around a housing means or drill collar in spaced relation from one another. A transmitting circuit alternately supplies an oscillating drive signal to each transmitting antenna with a sufficiently high frequency such that one and then the other of the transmitting antennas radiates an electromagnetic wave signal which propagates through the formation. Two receiving antennas are located equally spaced between the transmitting antennas to produce pick-up signals from the electromagnetic wave propagating through the formation. Each receiving antenna includes a single turn coil connected in series with a capacitor to provide a reduced impedance circuit to resonate in the frequency region embracing the oscillating drive signal.

Abstract: Methods of operation of an apparatus having at least two pairs of voltage measurement electrodes vertically disposed in a cased well to measure the resistivity of adjacent geological formations from inside the cased well. During stationary measurements with the apparatus at a fixed vertical depth within the cased well, the invention herein discloses methods of operation which include a measurement step and subsequent first and second compensation steps respectively resulting in improved accuracy of measurement. The invention also discloses multiple frequency methods of operation resulting in improved accuracy of measurement while the apparatus is simultaneously moved vertically in the cased well. The multiple frequency methods of operation disclose a first A.C. current having a first frequency that is conducted from the casing into formation and a second A.C. current having a second frequency that is conducted along the casing.

Abstract: A rotational speed detector for an internal combustion engine comprises a waveform processor for eliminating pulses generated within a predetermined period of time after a certain pulse appears and a measuring circuit for measuring a rotational speed based on outputs from the waveform processor. The waveform processor of the rotational speed detector thus eliminates the effects of such an unexpected pulse generated, for example, by the vibration of the ignition coil for the engine. Consequently, the measuring means detects the rotational speed accurately without measuring the unexpected pulse.

Abstract: A magnetoresistive sensor requires only two electrical connections to operate. The magnetoresistive sensor uses a hammerhead design and a barber pole array. Blocking capacitors are used to define two signal paths, one for a DC sense current, and one for an AC data signal. The blocking capacitors provide an electrical short to AC signals across wing regions of the magnetoresistive sensor. The blocking capacitors are fabricated directly upon a wafer which carries the magnetoresistive sensor.

Abstract: An induction tool including a coil array having a plurality of transmitter coils and a plurality of receiver coils. Each plurality of coils is symmetrically arranged on an insulated mandrel about a selected point. The induction tool also includes an oscillator circuit that provides an alternating frequency signal to the transmitter coils. A receiver circuit is connected to the receiver coils to measure signals indicative of the voltages induced on these receiver coils to the surface. By varying the spacing between the receiver coils and transmitter coils it is possible to independently vary the vertical and radial measurement capabilities of the tool of the present invention. A dual induction tool having high vertical resolution is also disclosed. The dual induction tool includes a pair of transmitter/receiver coil arrays, each transmitter/receiver coil array having a different transmitter-to-receiver coil spacing and substantially indentical vertical resolution.

Abstract: A wheel speed sensor apparatus for detecting the rotational speed of a road wheel of an automotive vehicle. The apparatus includes a toothed rotor rotatable with a road wheel of the vehicle. A sensor main body contains an element which produces an electical signal in response to adjacent passage of the rotor teeth upon rotation of the sensor rotor. The sensor main body is fitted inside inside a metallic sleeve in a manner such that a tip end section of the sensor main body is in close proximity to the sensor rotor. The metallic sleeve is fitted in the installation hole. The installation member is made of aluminum or aluminum alloy and is connected with the base section of a suspension strut of the vehicle.