Abstract: A method of monitoring electromagnetic properties of a subsurface formation may include: obtaining a resistivity distribution in the subsurface formation; identifying sensor positions along a borehole; determining an effective resistivity of each region around a sensor position; deriving from the effective resistivities of regions associated with each sensor position an optimum resonance frequency; tuning an array of sensors to provide each sensor with the optimum resonance frequency; deploying the sensor array in the borehole; and collecting electromagnetic field measurements. Each sensor may include: a coil antenna positioned in a subsurface formation having a resistivity, the coil antenna generating a induced voltage signal from an electromagnetic field in the subsurface formation; and a resonant modulation circuit that converts the induced voltage signal into a telemetry signal, the resonant modulation circuit having a resonance frequency optimized for said formation resistivity.

Abstract: The invention relates to a portable equipment item for locating metal objects to perform an accurate location of metal objects detected by other means, which comprises at least one proximity locator (11), or pointer, comprising a detection coil as well as control means capable of generating the excitation signal for the detection coil, of performing the detection of echoes originating from metal objects from the electromagnetic signals received by the detection head and of alerting the operator when a detection is made. The control means of the proximity locator (11) further comprise radio communication means configured to exchange information with a remote equipment item comprising communication means functionally compatible with the communication means of the device according to the invention. In a preferential configuration, the equipment item also comprises an operator headset (21) equipped with such communication means.

Abstract: A secondary unit arrangement of an inductive power transfer system includes a secondary unit having a secondary winding structure for receiving a magnetic or electromagnetic field generated by a primary unit, a detector device including plurality of detection elements for detecting an arrangement comprising the primary unit, a determination unit for determining at least one electrical property of the detector device with respect to different regions of an arrangement, thereby generating determination results consisting of a determination result for different regions of the arrangement, a comparison unit for comparing the determination results with existing information about the arrangement to be detected, wherein the existing information includes information about expected values for the different regions of the arrangement, thereby generating a comparison result, and a decision unit for deciding from the comparison result whether the determination results indicates that the detector device has detected the a

Abstract: A position detecting system detects and responds to the movement of a target through a sensing domain area of a plane. The movement causes the amount of the target that lies within a sensing domain area to change. A portion of the target always lies within at least one of the sensing domain areas of the plane.

Abstract: A position detecting system detects and responds to the movement of a target through a sensing domain area of a plane. The movement causes the amount of the target that lies within a sensing domain area to change. A portion of the target always lies within at least one of the sensing domain areas of the plane.

Abstract: Integrated circuit comprising a sensing unit that includes a sensing circuit, two conductors and a magnetic storage element. The sensing circuit monitors a voltage drop across the element when a current is passed between the conductors with the element in between. The voltage drop is pre-calibrated to indicate a change in conductivity in the element that is caused by an external magnetic field. Advantageously, this indication is usable particularly for assessing a possible data corruption in a magnetic memory circuit in the integrated circuit, due to stray and external magnetic fields. Methods of using the sensing unit are also proposed.

Abstract: A locator for locating a buried electromagnetic marker is operable to generate a test signal in order to validate that the locator is operating in accordance with calibration data. The locator comprises a transmission antenna and a first reception antenna. The transmission antenna is configured to generate a first oscillatory magnetic field to couple with an electromagnetic marker and the first reception antenna is configured to receive an oscillatory magnetic field emitted by the electromagnetic marker. In order to validate the operation of the locator, the transmission antenna is configured to generate a test oscillatory magnetic field, and the first reception antenna is configured to receive the test oscillatory magnetic field and thereby generate a first detected test signal.

Abstract: Metal detectors use graphical displays offering many analysis methods and user options which were not possible before. The new graphical detector displays allow new ways to display target information that enable better methods of analyzing and viewing target data. Graphical detectors have menu structures with dozens of operating parameters which can be modified by the user. Some of these parameters are able to be changed on-the-fly without having to suspend detector operation.

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 locator for locating a concealed conductor comprises a first field detector operable to detect an alternating magnetic field along a first axis parallel to a primary axis of the locator; a second field detector, displaced from the first field detector and operable to detect an alternating magnetic field along a second axis parallel to the primary axis of the locator; and a processor operable to calculate a difference between a field detected by the first detector and a field detected by the second detector, and to calculate an indication of the lateral displacement of the concealed conductor from the primary axis of the locator using the difference.

Abstract: A new hybrid metal detector combines induction balance and pulse induction technologies. Target signals are generated from a transmitted wave that has both induction balance and pulse current inducing characteristics and uses pertinent sampling of the receive data. Combining the two data sources provides eddy current target identification while excluding ground permeability and remanence obscuration.

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 buried object detector comprising: a loop antenna and an RF source, the RF source coupled to the loop antenna and arranged to feed the loop antenna with an RF signal, the detector further comprising a detector circuit coupled to the loop antenna and arranged to detect changes in the quality factor of a resonant circuit formed by the loop antenna, wherein the loop antenna is arranged to magnetically couple with a buried object, thereby reducing the quality factor of the resonant circuit.

Abstract: An apparatus for evaluating an earth formation, the apparatus including: a logging tool configured to be conveyed through a borehole penetrating the earth formation; a coil inductively coupled to the earth formation, the coil being disposed at the logging instrument; and a circuit coupled to the coil wherein the circuit and the coil form an oscillator circuit, the oscillator circuit being configured to oscillate when a circuit parameter of the oscillator circuit satisfies an oscillation criterion, the circuit parameter being related to a property of the earth formation.

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 hybrid-technology metal detector, using pulse-induction and sine-wave excitation of the transmitter coil alternately, in rapid succession. The energy stored in the transmitter coil, in the pulsed mode, is used to shock-excite a high-Q circuit formed by the coil and a parallel capacitor into oscillations in the sine-wave mode. The multiplicative action of the circuit Q causes high currents to flow in the transmitter coil, causing high fluxes to be impressed on the searched area, with increased sensitivity as a result. Using a linear coil-current ramp to assess and minimize the coupling between the transmitter and receiver coils permits effective separation of the reactive and resistive components of the target signals, making accurate identification of targets possible.

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: An apparatus for releasably attaching a pushing tool to one work piece such that a pushing force can be applied to a second work piece and allow alignment of the two work pieces for joining the work pieces together.

Abstract: A cantilever control device is provided that can prevent, in an atomic force microscope, self-excited oscillation of a cantilever from stopping and prevent a probe of the cantilever from coming into contact with a measurement object. In the atomic force microscope, a cantilever control device 1 is constituted from a cantilever 10 having a probe 12, an actuator 20 that causes self-excited oscillation in the cantilever 10, an oscillation velocity detector 30 that detects the oscillation velocity of the cantilever 10, a displacement calculator 32 that calculates the oscillation displacement of the cantilever 10, and a controller 40 that generates a signal for driving the actuator 20. A feedback control signal S is represented as (K?G·x2)·dx/dt, where x is the oscillation displacement of the cantilever 10, dx/dt is the oscillation velocity of the cantilever 10, and both K and G are feedback gains of a positive value.

Abstract: A method and system for improving power distribution and/or current measurement on a printed circuit board is disclosed. According to the invention, a first power plane adapted for current measurement includes a first segment to which a current source is connected and a second segment to which other devices may be connected, forming the current load. A third segment is used to measure the current between the first segment and the second segment through two vias that link two points of the third segment to, preferably, two pads of the external layer. In a preferred embodiment, vias are connected to the first segment so that current flow in the third segment is linear, to improve and simplify current determination. The resistivity between the pair of vias may be computed or estimated using calibrated currents.

Abstract: The subject of invention is a portable electromagnetic metal detector, of the type comprising a detection head placed at the end of a support stick, the detection head includes a transmitting coil and a receiving coil. The metal detector has, an electronic command and control box making it possible to implement the detection head. An operator headset is provided for allowing the detector to transmit an audio detection signal to the operator. According to the invention, the detection head comprises all the means for generating a transmission signal and for analysing the signal received. The detection head, the electronic box and the operator headset furthermore comprise radio transmission means for establishing a multipoint wireless communication network between these three elements. This communication network advantageously makes it possible to provide a detector that does not comprise any wired links and to implement the detector according to the invention in various configurations.

Abstract: An apparatus for locating underground cast iron pipe joints having an electrically driven resonant coil generating an alternating magnetic field and two resonant sensor coils disposed within the alternating magnetic field, each of the resonant sensor coils having an independent magnetic reluctance circuit. A device is provided for comparing electrical currents induced in each of the resonant sensor coils and a device is provided for indicating a relative magnitude of the electrical currents.

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 pulse induction metal detector includes a pulse transmitter coil for generating and transmitting a first electromagnetic signal and a receiver coil for detecting and amplifying a second electromagnetic signal emitted by a nearby metal target due to eddy currents generated in response to the first electromagnetic signal. The receiver coil is a coil of wire having multiple loops. At least one switch is coupled with the coil of wire such that when the switch is in its open position, the coil of wire is a broken circuit. In this condition, the inductive properties of the receiver coil are minimized during abrupt transmitter coil turn off. The number of switches per coil loop can be varied to achieve varying levels of sensitivity.

Abstract: A metal detector capable of operating in both a time-domain mode and a frequency-domain mode includes a transmitter component and a receiver component. The transmitter component includes a transmitter coil that can receive both an AC and DC current source for frequency-and time-domain operation respectively. The AC signal is impressed on the DC signal such that while the transmitter coil is charging, frequency-domain sensing is occurring and when the transmitter coil is switched off, time-domain sensing is occurring. The receiver component uses a primary field bucking method to ensure that both time-and frequency-domain modes can operate with the receiver coil.

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: A method of resetting an active emissions system error indictor associated with a vehicle. The method comprises performing a first requesting step and a second requesting step until the active emissions system error indicator resets in response to the first or second requesting steps. In one embodiment, the first requesting step comprises requesting a first type of information (e.g., information from a first vehicle oxygen sensor) from a vehicle computer associated with the vehicle, and the second requesting step comprises requesting a second type of information (e.g., information from a second vehicle oxygen sensor) from the vehicle computer. In a particular embodiment of the invention, an electronic tool, such as a bi-directional scan tool, is used to perform the first and second requesting steps.

Abstract: A metal detecting device for the detection of a metal object concealed in shoe or on a leg of a subject, including: a housing with a platform having an upper surface with indication areas thereon for the correct positioning of each of a subject's feet, left-foot and right-foot electromagnetic coils under the indication areas connected to a power supply via an oscillator and a switch, an electromagnetic shield divider between the left-foot and right-foot electromagnetic coils, a detection system for the detection of the placement of the subjects feet on the indication area, a processing unit for processing signals from the electromagnetic coils and detection system, and a display connected to the processing unit for displaying a warning signal if metal is detected.

Abstract: A method is disclosed for determining a direction of a target formation with respect to an instrument in a wellbore. The target has an electrical conductivity different than earth formations surrounding the wellbore. The method includes inducing time varying electromagnetic fields in the formations surrounding the wellbore. The electromagnetic fields have at least some components along mutually orthogonal directions. Voltages induced by the time varying electromagnetic fields are detected. The detecting is performed to have at least some component along mutually orthogonal directions. The direction of the target is calculated from the detected voltages.

Abstract: A Surface to Underwater Viewing Device Attachment for a Metal Detector. A tube, with clear sheet glass cut to shape and inserted and sealed in one end to make it waterproof, the other end being left open. The tube is long enough to keep the opened end out of the water. The tube is mounted a small distance from, and attached to, the body of the metal detector. The tube is positioned parallel, or almost parallel, at angles that allow the operator to see through the tube, while holding the metal detector. The operator may now see clearly below the surface of the water and see where the search coil on the metal detector has passed over.

Abstract: The invention relates to a metal detector with at least one driver circuit 2, at least one transmitter winding 4 having two external terminals 4a, b, and at least one receiver winding 5 having two external terminals 5a, b. The efficiency is increased in comparison to conventional metal detectors by providing at least one tap subdividing the transmitter winding 4, whereby a transformed electrical AC voltage is provided at the external terminals 4a, b of the transmitter winding 4 by the driver circuit via the tap 4c.

Abstract: A hand tool has a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which an inductor is positioned and connected to metal detection circuitry. A pulse generator applies current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type. Signal variations resulting from temperature changes when the probe is inserted into soil are compensated for by detecting a signal proportional to the coil current during the pulse and subtracting a scaled portion of that signal from voltage samples.

Abstract: A process for the detection of a defect of an automotive vehicle battery includes analyzing the time dependence of the discharge voltage across the terminals of the battery. This process has the steps of measuring at least two successive values of the discharge voltage of the battery, during the phase of cranking the engine of the automotive vehicle, for at least two consecutive top dead center points, taking a difference of the measured voltage values, and deducing therefrom whether the battery is charged or defective. The process is built into an electronic computer carried on board the automotive vehicle.

Abstract: A hand tool has a handgrip attached to a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which at least one inductor is positioned and connected to metal detection circuitry. The preferred circuitry has a pulse generator applying current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. An asymmetric magnetic field pattern about the probe is aligned with a direction pointing indicium on the handgrip and provides directional sensitivity. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type.

Abstract: A hand tool has a handgrip attached to a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which at least one inductor is positioned and connected to metal detection circuitry. The preferred circuitry has a pulse generator applying current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. An asymmetric magnetic field pattern about the probe is aligned with a direction pointing indicium on the handgrip and provides directional sensitivity. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type.

Abstract: A hand tool has a handgrip attached to a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which at least one inductor is positioned and connected to metal detection circuitry. The preferred circuitry has a pulse generator applying current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. An asymmetric magnetic field pattern about the probe is aligned with a direction pointing indicium on the handgrip and provides directional sensitivity. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type.

Abstract: A hand tool has a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which an inductor is positioned and connected to metal detection circuitry. A pulse generator applyies current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type. Signal variations resulting from temperature changes when the probe is inserted into soil are compensated for by detecting a signal proportional to the coil current during the pulse and subtracting a scaled portion of that signal from voltage samples.

Abstract: A hand tool has a handgrip attached to a groundpiercing probe, which is manually insertable in the soil. The probe has a chamber in which at least one inductor is positioned and connected to metal detection circuitry. The preferred circuitry has a pulse generator applying current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. An asymmetric magnetic field pattern about the probe is aligned with a direction pointing indicium on the handgrip and provides directional sensitivity. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type.

Abstract: A hand tool has a handgrip attached to a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which at least one inductor is positioned and connected to metal detection circuitry. The preferred circuitry has a pulse generator applying current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. An asymmetric magnetic field pattern about the probe is aligned with a direction pointing indicium on the handgrip and provides directional sensitivity. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type.

Abstract: A hand tool has a handgrip attached to a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which at least one inductor is positioned and connected to metal detection circuitry. The preferred circuitry has a pulse generator applying current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. An asymmetric magnetic field pattern about the probe is aligned with a direction pointing indicium on the handgrip and provides directional sensitivity. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type.

Abstract: A hand tool has a handgrip attached to a ground-piercing probe, which is manually insertable in the soil. The probe has a chamber in which at least one inductor is positioned and connected to metal detection circuitry. The preferred circuitry has a pulse generator applying current pulses to an inductor for inducing eddy currents in a buried target object. After the pulse terminates, the decaying coil voltage is sampled at different times to detect both the presence and range of the object, as well as the type of metal in the object. An asymmetric magnetic field pattern about the probe is aligned with a direction pointing indicium on the handgrip and provides directional sensitivity. The coil voltage samples are applied to signaling circuitry, which provides an audible signal which is a series of bursts of an audio tone. The pitch of the audio tone signals the presence, range and bearing of the buried metal object, while the pulse rate of the bursts signals the metal type.

Abstract: Sensors, systems and methods for measuring magnetic field strengths in both AC and DC magnetic fields by using CMR material in tunable, radio-frequency LC oscillators are disclosed.

Abstract: A metal detector that is to be attached to a human appendage and preferably the wrist and hand of a human. A metal detector includes a housing which is to be worn strictly by the human hand or the hand and the wrist. One version of the metal detector would be in the form of a glove. The second version would be in the form of a flexible base which is mounted between the hand and the wrist by a strap arrangement. Within both versions, there is a search coil located in the palm area of the hand. A metal detection circuit battery source is mounted on the portion of the housing that is located directly against the backside of the hand.

Abstract: An oscillator 12 outputs a constant frequency as a metal object is brought close and this frequency forces oscillation of an oscillating circuit 11 which is sensitive to this metal object, at a level significantly below the critical natural frequency of the oscillating circuit. The oscillating signals S1, S2 are applied to the two inputs of a phase detector 15, such that they can be changed over by means of an inverter device 17, so that the detector can be configured in ferrous mode or in non-ferrous mode.

Abstract: An object sensing system (10) employs a resonant sensor (20) that receives drive energy coupled from an oscillator (12) operating at a frequency equal or close to the resonant frequency of the resonant sensor. The resonant sensor preferably includes an planar winding (60) that maximizes its distributed inductive and capacitive components, which are sensitive to a proximal conductive, nonconductive, magnetic, or nonmagnetic object (22). The resonant sensor is electrically connected in one leg of a voltage divider that produces a changing output signal voltage in response to resonant frequency changes caused by the object in proximity to the resonant sensor. The signal voltage is amplified, filtered, and processed to extract relevant data indicative of the presence, distance, movement, or proximity of the object.

Abstract: A compact hand-held metal detector that detects small ferrous and non-ferrous metal objects, that has a detection pattern in three planes, and that includes a plurality of detection alarm indications including visual, audio, and tactile detection alarm indications is provided. The invention includes a single small detection coil combined with an electronic control circuit that permits the coil and associated electronic components to be mounted adjacent each other in a compact enclosure. The coil provides a spherical detection pattern that is active in all three planes which detects metal objects in any orientation with respect to the coil. Upon detection of a metal object, the detector provides a visual and audio or tactile alarm indication.

Abstract: An integrated circuit for measuring the distance houses an oscillator in a package. Further, a plane inductor is provided on the surface of the package housing the oscillator. The plane inductor is connected to the oscillator so as to specify a frequency of the oscillator. If conductive material approaches the surface of the package, the frequency of the oscillator is varied by means of the plane inductor. The approaching distance of the conductive material is detected by detecting the frequency of the oscillator. The conductive material is mostly metal, however, the integrated circuit for measuring the distance can measure the approaching distance of non-metal conductive material such as conductive liquid.

Abstract: The invention relates to an exercise mine system for training in mine detection. The invention including a passive oscillating circuit tuned to a certain frequency. This circuit being designed to be detected by another active oscillating circuit carried by an individual or vehicle.

Abstract: A universal inductive proximity detector including an oscillator, whose oscillating circuit is powered by a current source. A fixed frequency master oscillator 16, which controls the current source 18, is coupled to the oscillator 10 so that the current source excites the oscillating circuit with a pulsed direct current.