Abstract: A winding of an antenna of a metal detector, the winding includes multi-turn wire with both ends connected to the metal detector; and at least one resistive component for connecting a first part of the winding to a second part of the winding. The first part or the second part are not both ends of the winding. The resistive component is configured to damp an internal resonance of the winding with an order greater than 1.

Abstract: The present disclosure provides a foldable portable metal detector including: a detection coil disk; a waterproof circuit protection compartment; a circuit component; a folding and fixing component; a fastening component; and an extension rod; the circuit component is inserted into the waterproof circuit protection compartment; the extension rod is fixedly connected to the waterproof circuit protection compartment; the circuit component is electrically coupled to the detection coil disk; the detection coil disk is provided with a bracket provided with a first through-hole and a second through-hole; the fastening component is provided with a bolt and a fixing column; the waterproof circuit protection compartment is provided with a connector provided with a connection hole; the bolt penetrates the connection hole and the first through-hole in sequence, the fixing column penetrates the second through-hole; and the waterproof circuit protection compartment is selectively rotated around the bolt.

Abstract: A foldable metal detector includes a detection coil disk, a waterproof circuit protecting chamber, a circuit component fixedly disposed in the waterproof circuit protecting chamber, folding fixing components, fastening components, an extending rod fixedly connected to a tail end of the waterproof circuit protecting chamber, and a BLUETOOTH remote control component configured to control the foldable metal detector. The extending rod is manually detachable from the waterproof circuit protecting chamber. The circuit component is electrically connected with the detection coil disk. Brackets are disposed on the detection coil disk. Each bracket includes a first through hole and a second through hole. The fastening components include bolts and fixing columns. Connecting heads with connecting holes are disposed on the waterproof circuit protecting chamber. Each bolt passes through each connecting hole and each first through hole. The bolts are movably connected to the folding fixing components.

Abstract: Systems and methods for shielding a metal detector head include placement of conductive shielding around the coils of the head to reduce the effects of capacitance variation between the coils and their surroundings.

Abstract: A sensor device and a method for the geoelectrical prospecting of the location, the (stratographic) arrangement, and the course of raw mineral deposits and of the adjoining rock delimiting these deposits, particularly in the continuous working of the mineral deposits, having a sensor head whose front surface forms the sensor measuring surface, and at least one electrode. The sensor head can make contact with a ground surface, and a central electrode and a plurality of outer electrodes distributed geometrically uniformly around the central electrode are arranged on the sensor measuring surface, the central electrode and the outer electrodes being electrically conductive and electrically separated from one another.

Abstract: A method and apparatus is provided for collecting reservoir data. The method includes providing one or more electromagnetic sources for generating an electromagnetic field in a reservoir and providing one or more electromagnetic sensors equipped with capacitive electrodes. The electromagnetic source is located separately from the electromagnetic sensor. The electromagnetic sensor may either be located within a well or at the surface, is capable of measuring the electromagnetic field in three dimensions, and may be isolated from the well fluids. The data collected by the electromagnetic sensors can be used to create a model of the oil reservoir, including the water saturation.

Abstract: A self-calibrating magnetic field monitor is disclosed. In one embodiment, a magnetic field sensor repeatedly generates an electronic signal related to the magnetic field. In addition, a calibration module generates a relative baseline signal based on an average value of the electronic signals for a given time period. A comparator compares the electronic signal with the relative baseline signal and generating an output signal if a difference in the comparing is greater than or equal to a threshold.

Abstract: The present disclosure relates to determining the attenuation of an electromagnetic signal passing through a conductive material. An antenna is provided and placed in relatively close proximity to the conductive material. An alternating current is passed through the antenna and the impedance of the antenna is measured. The attenuation is determined using the measured impedance. A single frequency measurement may be made, or multiple measurements using different frequencies may be made. Grouped parameters based on properties of the material and the frequency of the current are used to relate the coil impedance to the attenuation. A current frequency for which the ratio of the antenna's resistive part of the impedance to the angular frequency of the current is substantially insensitive to at least one of the parameters is preferred.

Abstract: A method of determining anisotropy in a borehole is disclosed. An array of measurements along the borehole is obtained and a first depth in the borehole is selected. An arbitrary plane oriented with respect to the borehole at the first depth is designated and an anisotropy for the first depth with respect to the arbitrary plane is determined. The arbitrary plane is repositioned at the first depth and an anisotropy for different positions of the arbitrary plane at the first depth is determined. A minimum anisotropy coefficient with respect to the arbitrary plane at the first depth is identified based on anisotropy for different positions of the arbitrary plane. An anisotropy tensor for the first depth is then identified.

Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: There are provided a crack determining device capable of determining, in real time and with precision, the fact that a crack has occurred in a solder layer, and a semiconductor device comprising same.

Abstract: A self-calibrating magnetic field monitor is disclosed. In one embodiment, a magnetic field sensor repeatedly generates an electronic signal related to the magnetic field. In addition, a calibration module generates a relative baseline signal based on an average value of the electronic signals for a given time period. A comparator compares the electronic signal with the relative baseline signal and generating an output signal if a difference in the comparing is greater than or equal to a threshold.

Abstract: A system for measuring a true vertical depth of a downhole tool is provided. The system includes: a first optical clock located at a first depth and having a first frequency; a second optical clock disposable at a downhole location and having a second frequency at the downhole location; and a processor for receiving the first frequency and the second frequency, and calculating a true vertical depth of the second optical clock based on a difference between the first frequency and the second frequency. A system and computer program product for measuring a true vertical depth of a downhole tool are also provided.

Abstract: A method of determining the nature of a submarine or subterranean reservoir having an electromagnetic characteristic is described. The method comprises analyzing data associated with the application of a time varying electromagnetic field from above the reservoir using a data analysis methodology that does not utilize an estimate of the reservoir's geometry in determining one or more characteristics of the reservoir.

Abstract: Location determination is performed using a transmitter including an elongated generally planar loop antenna defining an elongation axis. The elongation axis is positioned along at least a portion of a path. A magnetic field is then generated which approximates a dipole field. Certain characteristics of the magnetic field are then determined at a receiving position radially displaced from the antenna elongation axis. Using the determined certain characteristics, at least one orientation parameter is established which characterizes a positional relationship between the receiving position and the antenna on the path. The magnetic field may be transmitted as a monotone single phase signal. The orientation parameter may be a radial offset and/or an angular orientation between the receiving position and the antenna on the path. The antenna of the transmitter may be inserted into a first borehole to transmit the magnetic field to a receiver inserted into a second borehole.

Abstract: A search apparatus and related method facilitate the final stage of a search for a buried person carrying a transmitter. When the searcher is in the close vicinity of the buried transmitter, the search enters a point-localization phase where the apparatus displays a representation of the current target distance from the apparatus to the buried transmitter as well as a representation of a previously-stored value for the target distance. By comparing the current distance to the previously-stored distance, the searcher can readily see whether the apparatus is getting closer to the buried transmitter or further away. Preferably, graphic symbols are displayed to represent the current distance and the previously-stored distance. The display can also provide a representation of whether the current distance is greater than or less than an immediately preceding distance that has been stored.

Abstract: A new approach for locating an underground line described herein remains accurate in the face of bleedover by including both amplitude and phase from at least two magnetic field strength sensors in the measurement set. A numerical optimization step is introduced to deduce the positions and currents of each of several cables, of which one is the targeted cable and the others are termed bleedover cables. Furthermore, some embodiments of the method accounts for practical problems that exist in the field that relate to reliable estimation of cable positions, like the phase transfer function between transmitter and receiver, the estimation of confidence bounds for each estimate, and the rejection of false positive locates due to the presence of noise and interference.

Abstract: A radio mode selectivity block 41 for a detector 1 for detecting a buried current carrying conductor comprises a plurality of beat frequency oscillators 53 to center the bandwidth of detection of the detector 1 on target very low frequency (VLF) frequency bands. The frequencies of the beat frequency oscillators are chosen to fall within the VLF frequency bands used in a number of countries, so that the detector 1 can be used in radio mode in these countries without the need for local configuration.

Abstract: A strip array antenna including a number of conductors (14) that are connected to ground or virtual ground though at least one reactive component (150). The apparent electrical length of conductors (140) is tuned so that it equals an integer multiple of a quarter wavelength at the operating frequency.

Abstract: A new digital architecture for metallic pipe and cable locators, providing accurate estimation of the fundamental locate parameters, electromagnetic signal strength and signal direction, and utilizing a nested Digital Phase-Locked Loop (DPLL) structure is disclosed. The obstacles to signal direction measurement in low SINR environments using the signal select method are overcome and a more precise phase comparison between the carrier and the FM modulation signals is obtained. The architecture further significantly reduces analog front-end hardware requirements, offers wider resistance to component tolerances, lower calibration and test time, and provides flexible frequency selectivity. Locators according to the present invention provide accurate estimation of the fundamental physical parameters of line location (electromagnetic signal strength and signal direction) in extremely noisy environments, using Digital Signal Processing (DSP) methods.

Abstract: An induction logging tool is used on a MWD bottom hole assembly. Due to the finite, nonzero, conductivity of the mandrel, conventional multi frequency focusing (MFF) does not work. A correction is made to the induction logging data to give measurements simulating a perfectly conducting mandrel. MFF can then be applied to the corrected data to give formation resistivities.

Abstract: Control apparatus for a horizontal boring tool is described which drives a boring lance via boring rods. The tool includes an input interface for receiving actual values of controlled variables of the horizontal boring tool, and an output unit for issuing control signals for controlling the horizontal boring tool. Between the input interface and the output unit is provided a fuzzy control unit which determines the control signals for activation of the horizontal boring tool from the actual values of the controlled variables and the desired values for the controlled variables by fuzzy logic while taking into account heuristic process values. The control apparatus permits automatic operation of the horizontal boring tool with good course steering and high precision.

Abstract: A pulse induction metal detector having high efficiency and sensitivity. Within the scope of the invention is a high efficiency hand-held metal detector for detecting a metal object, comprising a coil and a source of current flow in the coil. The source is adapted to produce one or more pulses of current in the coil. Preferably, at least two of the pulses are spaced apart in time at least about 20 microseconds during which current flow in the coil is substantially constant. The metal detector also comprises a detecting circuit for detecting a response to the current pulses, and a sampling circuit for sampling the response at predetermined times at least during the time of one of the pulses.

Abstract: A metal detector (10) which uses a metallic test sphere (5) to pass with the product through the detector head (2) at periodic intervals. The frequency generator (21) which generates the signal sent to the oscillator coil (11) is capable of operating on numerous frequencies in the 50 kHz to 2 MHz range. The product is passed through the detector head (2), with and without the sphere (5) present, for each of the operating frequencies. The detected signal from the product and the product with metal is characterized for each of the operating frequencies. In this manner the frequency which produces the highest ratio of product with metal present signal to product signal without metal present can be identified. A second version of the metal detector (40) uses a frequency synthesizer (43) which may be rapidly scanned through a range of frequencies while the product is passing through the detector head (41).

Abstract: A FM (VHF) infrared wireless digital metal detector is disclosed having a sealed aluminum radiation shield and dielectric case, with a infrared phototransistor detector and krypton bulb arranged to relay detection data to meter within a clustered instrument combination down in front of metal detector unit.

Abstract: A device is disclosed for use with heterodyne metal detectors to eliminate the indication of the detected presence of certain specific metals to the operator. A specially tuned circuit rotated adjacent the detector interacts with the circuitry of the detector to eliminate the audio and visual response of the detector to certain predetermined undesired metal objects. The device includes two coils, one of low impedance and high resistance and the other of high impedance and low resistance.

Abstract: An assembly formed by an electronic circuit in which a microprocessor is included that emits a signal from which additional signals are generated by a frequency synthesizer. These signals are applied to coils which form the emitting antenna, after being filtered and amplified. From these signals, the sample signal is generated and is picked up by other receiving antennas. After being amplified and filtered and all the distortion elements removed, the picked up signals are applied to proper frequency filters to obtain at the output signals having amplitudes proportional to those generated in the sample.

Abstract: A conventional magnetometer produces an output signal (10) which comprises a series of pulses (12, 14, 16). Each of these pulses has a beat frequency maximum. These pulses are input to a comparator (50) which makes a comparison to a threshold voltage V.sub.0 to produce a bi-level detected signal at a line (62). The detected signal is input to an integrator (52) which produces a series of pulses (78, 80, 82) corresponding respectively with the magnetometer output signal pulses (12, 14, 16). The two states of the detected signal corresponding to positive and negative integration. The time period for the positive integration is proportional to the beat frequency maximum time width period for the corresponding magnetometer output signal pulse. Thus the integrated pulses (78, 80, 82) have an amplitude which is a measure of the maxima time width periods for the corresponding magnetometer signal pulses.

Abstract: An inductive pressure sensor is proposed which has at least one coil embodying a frequency-determining part of an oscillator and disposed at a distance from a diaphragm which is deflectable in accordance with pressure. When pressure is exerted on the diaphragm, the inductance of the coil and thus the oscillator frequency are shifted. The coil is a flat, spiral element and the diaphragm has a surface of highly conductive or ferrite material. It is further provided that two oscillators of identical design and having corresponding coils are used, operating under identical thermal conditions. Either one oscillator operates at a fixed frequency, so that both absolute-pressure measurements and differential-pressure measurements relative to ambient pressure can be made, or else the two oscillators can be detunable in accordance with pressure, so that differential-pressure measurements between two media can be made. The output signal is then obtained by mixing.

Abstract: A vehicle detector installation includes a loop oscillator the loop of which is laid in the roadway and which is locked in operation to a voltage controlled oscillator (VCO). Vehicle detection is effected by a phase detector monitoring the phase difference between the oscillators. The VCO is incorporated in a phase-lock loop (PLL) that is capable of locking to a multiple of a reference frequency oscillator over a range of multiples. To achieve the locking of the loop oscillator to the VCO, means are provided for disabling the normal operation of the PLL and sweeping the VCO over its range of frequency until the phase detector indicates that the loop oscillator and VCO frequencies are equal. This indication activates the PLL to its normal operation to pull the VCO and therewith the loop oscillator to an adjacent multiple of the reference frequency. The PLL is maintained by a repeated charge/discharge cycle of the VCO capacitor that is dependent on the phase of the reference oscillator and the VCO.

Abstract: An improved metal detecting device of the beat frequency oscillator type is provided which incorporates a method for determining the side of the zero beat frequency at which a search oscillator is operating. The device includes a search coil conveniently mounted which is part of a search oscillator. A reference oscillator is also provided, the output of which is digitally compared to that of the search oscillator by a digital phase comparator. The digital phase comparator output is applied through a low pass filter to a slope detector circuit. The slope detector output signal is supplied to both an audio output circuit and a filter/comparator. The audio output is sufficient to facilitate location of permeable and conductive substances. The output of the slope detector also contains information which is extracted by the filter/comparator and translated to an audible signal by an oscillator and the audio output circuit.

Abstract: A directional concealed object locator, say metal detector, employing a beat frequency oscillator and at least two search oscillators. The search oscillators each include a loop antenna which in part serves to determine the search frequency signal rate of each oscillator and functionally serves to produce an electromagnetic field of relatively large proportions from each loop antenna which is portably so orientable as to have the extended electromagnetic field lines, which emanate from each loop antenna, separately coupled to a buried, or otherwise obscured metal object and thereby produce changes in the search signal rate as the proximity therebetween is varied.

Abstract: A metal locator apparatus the preferred practice of which includes two electromagnetic field radiating inducers, which serve to act upon a metal object deposited in a covert medium from distinctly separate positions, including two separate search oscillators one of which is connected to each of the inducers thereby producing two output signals, each of which include distinctive frequency perturbations introduced by the proximal relationship of the metal object with the responsive inducer. The two signals are then each individually combined, or mixed with a common beat oscillator which action results in two output sets of sum and difference frequencies. By way of suitable filtering, the two difference frequencies come out as distinctly separate audio frequency signals the pitch of which fluctuates in direct accordance with the frequency perturbations appearing on the individual search oscillator combinative signals.