A metal detector detects when a target that is a desirable metal object is located within a medium. A signal is transmitted into the medium. A response signal is received from the medium. The response signal includes a secondary medium response signal from the medium and includes a secondary target response signal from the target when the target is located within the medium. The response signal is amplified to produce an amplified signal. Compensation circuitry perform transmit coil transfer function compensation on the amplified signal to produce a compensated signal. A notch module removes a resistive component of the secondary medium response signal from the compensated signal.

A sensor system for sensing the contents of a bore including a plurality of coils disposed behind a non-metallic lining. An oscillator circuit may be used to drive the coils to generate oscillating electromagnetic fields, and a detection circuit generates output signals from each coil representing a parameter of the electrical oscillations that depends on the contents of the bore. The coils may include a primary coil and a one secondary coil, wherein the oscillating electromagnetic field generated by the secondary coil has a lesser degree of interaction with the contents of bore than the oscillating electromagnetic field generated by the primary coil. The sensor system may use the output signal from the secondary coil to compensate the output signal from the primary coil for environmental effects.

An antenna arrangement. The arrangement uses four conductive loops, each within a distinct plane from the other conductive loops. The four conductive loops have a common center point. Each loop is within a dipole magnetic field, and detects a component thereof. By balancing the signals received between matched pairs of the conductive loops, the difference between the signals can be used to guide the antenna arrangement to a null point—that is—a point in the magnetic field where each pair of conductive loops is balanced. The antenna arrangement can further be used to determine the depth of the dipole field source using the magnitude of the field.

A metal object detecting device for a wireless charging device is provided and includes an object detection coil, a relay and an object detector circuit. The wireless charging device has a transmitter coil, a first digital signal processor and a receiver coil. The object detection coil is disposed above the transmitter coil. The relay is connected to the object detection coil. The object detector circuit is connected to the relay and the first digital signal processor. The transmitter coil transmits a power signal to the receiver coil within a power supplying time. The relay is turned on during an object detection time such that an oscillation signal is generated from the object detection coil and the object detector circuit as a basis for determining whether or not a metal object is close to the wireless charging device.

A system for metal detection comprises a single aperture comprising two or more sets of detection coils that surround the perimeter of the aperture. A flow path of materials passes through the aperture. Each set of detection coils comprises a transmitter and two receiver coils, with the transmitter coil located between the two receiver coils. Each set of detection coils is at a different angle relative to the flow path.

For near field communications, inductive coils coupled to each communicating circuit are brought close together so that there is inductive coupling between the two coils. Data signals can then be relayed between the two circuits without any direct connection between them. However, the system is susceptible to common mode noise, such as ambient EMI. In addition to the “active” coil pairs used for transmitting and receiving data, a pair of “passive” coils is provided, proximate to the active coil pairs, that is only used for detecting the ambient EMI. The EMI signals detected by the passive coils are processed by a noise detector/processor, and the noise detector processor then controls the transmitters and/or receivers to at least partially compensate for the detected EMI signals. Transmit power or receiver thresholds may be controlled by the noise detector/processor to improve the signal-to-noise ratio, or other compensation techniques can be used.

A programmable universal probe comprises a housing having a controllable electrical power source installed therein to provide the assemblies of the probe with a supply voltage, a controller which includes a system of accelerometer sensors, a microcontroller and a temperature sensor, an antenna assembly in the form of a ferrite transmitting antenna, and a radiated power meter, consisting of a current sensor with an amplifier. The antenna assembly is equipped with power switches and an input signal amplifier. The ferrite antenna is designed as a transceiver antenna which is capable of receiving the operating parameters of the probe in a programming mode and transmitting information to a receiver in an operating mode. The receiver and the programmable probe have a compatible data reception and transmission protocol.

Man-portable locator systems for locating buried or otherwise inaccessible pipes, conduits, cables, wires, and/or inserted transmitters using magnetic field antenna arrays and signal processing to analyze and display information about multiple buried utilities simultaneously are disclosed.

A programmable universal probe comprises a housing having a controllable electrical power source installed therein to provide the assemblies of the probe with a supply voltage, a controller which includes a system of accelerometer sensors, a microcontroller and a temperature sensor, an antenna assembly in the form of a ferrite transmitting antenna, and a radiated power meter, consisting of a current sensor with an amplifier. The antenna assembly is equipped with power switches and an input signal amplifier. The ferrite antenna is designed as a transceiver antenna which is capable of receiving the operating parameters of the probe in a programming mode and transmitting information to a receiver in an operating mode. The receiver and the programmable probe have a compatible data reception and transmission protocol.

A metal detector (1) has a drive coil (L61) and at least one detection coil (L62, L63) that detect fluctuations in a magnetic field generated by the drive coil, caused by metallic particles present in an inspected object. A multi-frequency transmitter unit (10) has a converter (4) with a plurality of drive switches (S41, S42; S43, S44) driven by a drive controller (2). The drive switches alternately conduct a drive current through the drive coil to generate an electromagnetic field with two or more different frequency components. A waveform of the drive current is determined, as is at least one pulse-modulated (PXM) signal corresponding to the determined waveform. The determined PXM-signal is determined online or is stored in a memory module (231; 232). The determined PXM-signal is generated and applied to control the drive switches. The drive current can be applied to the drive coil through an admittance unit (5).