Abstract: A system for measuring the conductivity of a material-under-test includes a support structure, an upper magnet mounted to the support structure and a free-floating magnet below the fixed magnet. The system includes a diamagnet positioned between the fixed magnet and the free-floating magnet such that the free-floating magnet floats in the air beneath the diamagnet and a rotation detection assembly configured to detect a rotation rate of the free-floating magnet, where the rotation rate is based on a drag torque effect of a material-under-test on the free-floating magnet. The system also includes a conductivity calculation unit configured to calculate at least one of a conductivity or a resistivity of the material-under-test based on the detected rotation rate of the free-floating magnet.

Abstract: A partial discharge detection device for detecting and measuring partial discharges in electric systems or components, which delivers signals having a form much resembling that of the radiated pulse, for improved identification and analysis. The device is of small size, totally insulated and self-powered, and allows measurements to be performed with the highest safety with no need for direct connection, thereby allowing operators to stand at a distance and avoid any system shutdown while making measurements. Furthermore, it can also detect and deliver the sync signal, which is obtained by picking up the supply voltage of the discharge generating components.

Abstract: An antenna device includes a sensor electrode having a capacitance configured to change upon an object approaching or contacting the sensor electrode, a sensor circuit electrically connected to the sensor electrode, an antenna section, and a substrate having the sensor circuit mounted thereon and having the sensor electrode fixed thereto. The sensor circuit is configured to detect the capacitance. The substrate is inserted into the antenna section. This antenna device allows components to be easily positioned during assembly.

Abstract: Disclosed is a proximity switch provided with an actuator unit and a sensor unit. The sensor unit is provided with an antenna coil, a transmitting circuit which transmits electromagnetic waves at a constant frequency to the antenna coil, a receiving circuit which detects external signals received by means of the antenna coil, and control circuits. The actuator unit is provided with an antenna coil, a power supply circuit which rectifies an electromotive force generated in the antenna coil, and a signal processing circuit which receives power supply from the power supply circuit, performs frequency-dividing to the signals received by means of the antenna coil, and transmits the signals from the antenna coil after the frequency-dividing. The control circuit of the sensor unit has memory for registering the frequency of the signals transmitted from the actuator unit.

Abstract: There is provided solution testing equipment which can detect an output variation of a THz oscillation device using a THz wave (h?) by contacting a liquid or cells on an RTD oscillation device, and can reduce the size and weight thereof. The solution testing equipment includes: a THz oscillation device configured to radiate the THz wave Is; a THz detection device configured to receive the THz wave Is; and a solution as a test object disposed on the THz oscillation device, in which the solution is tested on the basis of output characteristics of the terahertz wave varying in response to a relative permittivity of the solution.

Abstract: A seat for a passenger vehicle is provided that comprises a first sensor for detecting the presence or absence of an occupant in the seat and a second sensor for validating the seat occupancy. The seat further comprises a transmitter for transmitting a signal indicative of valid occupancy of the seat. The first sensor may be a non-contact, capacitive sensor and the second sensor may comprise a near-field communication device for receiving a seat validation code. A seat validation system may be established on a passenger vehicle such as a train, wherein a central controller may report on seat occupancy status for the vehicle.

Abstract: Disclosed is an SAR measurement method that is capable of securing sufficient power within a short period of time and always maintaining the intensity of measurement signals irrespective of the measurement frequency. With the SAR measurement method, a plurality of measurement modules each with a control unit for processing location information and SAR measurement values, a memory unit for storing data, an antenna for making signal transception with the external, and a storage battery charged by way of inductive power are prepared. Thereafter, the plurality of measurement modules are arranged and installed within a phantom formed with a homogeneous material that conforms to the electrical characteristics of human body tissue. An electronic product to be measured in SAR is mounted at a predetermined location of the phantom with a predetermined posture. A high frequency of several hundred megahertz (MHz) to several hundred gigahertz (GHz) is scanned toward the phantom.

Abstract: A method of making finger sensor packages may include advancing a flexible circuit tape along a predetermined path of travel. The flexible circuit tape may include a flexible layer and conductive traces thereon defining individual flexible circuits. The method may include, as the flexible circuit tape is advanced along the path of travel, securing a respective finger sensing integrated circuit (IC) and surrounding sensor package frame to each flexible circuit, applying at least one fluid fill material adjacent each finger sensor IC while using the corresponding sensor package frame as a dam to thereby define finger sensor packages, and stamping out the finger sensor packages from the flexible circuit tape to form at least one flush common edge of each sensor package frame and individual flexible circuit.

Abstract: A wireless in-plane strain and displacement sensor includes an electrical conductor fixedly coupled to a substrate subject to strain conditions. The electrical conductor is shaped between its ends for storage of an electric field and a magnetic field, and remains electrically unconnected to define an unconnected open-circuit having inductance and capacitance. In the presence of a time-varying magnetic field, the electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses. The sensor also includes at least one electrically unconnected electrode having an end and a free portion extending from the end thereof. The end of each electrode is fixedly coupled to the substrate and the free portion thereof remains unencumbered and spaced apart from a portion of the electrical conductor so-shaped. More specifically, at least some of the free portion is disposed at a location lying within the magnetic field response generated by the electrical conductor.

Abstract: Disclosed are systems, devices and methods related to scanners that can be utilized for multiple electrical and/or magnetic field measurements at different locations of a radio-frequency (RF) module. In some embodiments, a scanning system can include a miniature probe such as a magnetic probe, a fixture system configured to hold a device under test (DUT) such as an RF module, an operating system configured to operate the DUT, and a measurement system configured to obtain field strength measurements through the miniature probe at different locations of the DUT. Such measurements can yield a near-field distribution over a plurality of selected areas of the DUT, with each of the selected areas being smaller than an overall lateral area of the DUT. In some implementations, such a scanning system can be utilized to facilitate applications such as electromagnetic (EM) shielding designs.

Abstract: Systems, methods, and devices for an intrusion detection system are described herein. For example, one or more embodiments include transmitting a DSSS signal, receiving a reflected DSSS signal from a target, correlating the reflected DSSS signal and the transmitted DSSS signal, and determining a distance to the target based on the correlation between the reflected DSSS signal and the transmitted DSSS signal.

Abstract: A device for identifying a local coil property of a local coil for a magnetic resonance imaging scanner includes at least one label configured to transmit at least one identity number wirelessly. The device also includes at least one reading unit with a reading-unit antenna. The reading unit is configured to receive the at least one identity number. The device includes an identification apparatus configured to identify a local coil property of the local coil based on the at least one received identity number.

Abstract: An apparatus includes a stable local oscillator, which includes a first control loop. The first control loop includes a first voltage-controlled oscillator configured to generate a first output signal and a first phase-locked loop. The apparatus also includes a frequency up-converter configured to increase a frequency of the first output signal. The apparatus further includes a second control loop configured to receive the up-converted first output signal. The second control loop includes a second voltage-controlled oscillator configured to generate a second output signal and a second phase-locked loop. The second control loop may further include a mixer having a first input coupled to the frequency up-converter, a second input coupled to the second voltage-controlled oscillator, and an output coupled to the second phase-locked loop. A reference frequency source may be configured to generate a signal identifying a reference frequency and to provide that signal to the phase-locked loops.

Abstract: An RF sensing circuit with a voltage-controlled oscillator comprises a low noise amplifier (LNA), a voltage-controlled oscillator (VCO), a frequency demodulating unit, a bandpass filter (BPF) and a digital signal processing unit. The VCO has an injection signal input port and a voltage input port, wherein the injection signal input port is electrically connected with an output of the LNA. The frequency demodulating unit is electrically connected with an output of the VCO and the BPF is electrically connected with an output of the frequency demodulating unit. The digital signal processing unit is electrically connected with an output of the BPF and the voltage input port of the VCO.

Abstract: Disclosed is an electromagnetic wave information detection apparatus, including a photoelectric converter including first and second electrode layers; a charge generation layer that generates positive and negative charges by irradiation of an electromagnetic wave; and a charge transport layer; an electric potential imparting unit that imparts electric potentials to the first and second electrode layers; a detection unit; and a control unit controlling the electric potential imparting unit and the detection unit such that the electric potentials of the first and second electrode layers are equalized during a predetermined period of time between a process of imparting detection electric potentials to the first and second electrode layers to detect information carried by an electromagnetic wave of a previous irradiation and a process of imparting the detection electric potentials to the first and second electrode layers to detect information carried by an electromagnetic wave of a subsequent irradiation.

Abstract: The invention relates to a system for non-invasive data acquisition from a human or animal body 7, comprising an antenna for irradiating a portion of the said body, said antenna being connected to a source and a processor for collecting said data pursuant to said irradiation, wherein the antenna is a leaky wave antenna 1, 2, 3, 4 operable using a dielectric layer, the system being configurable so that the portion of the body 7 is at least partially used for the said dielectric layer.

Abstract: Analyze a hollow fiber filter module for defects by providing a membrane header assembly with a header having a conduit defined there-through by a wall with multiple holes and a hollow fiber membrane inserted into a hole, directing a probe device with a sensor through the conduit, receiving sensory response information with the sensor, the sensory response information containing information sufficient to identify defect in the form of a hole lacking a hollow fiber membrane, a hole that has a hollow fiber membrane inserted to a non-desired depth, or both and then interpreting the sensory response information to detect such defects if they exist.

Abstract: Provided is a touch-sensitive input apparatus including a capacitive sensor with a plurality of adjacent capacitive, touch-sensing regions for detecting a foreign object in close proximity to a surface of the capacitive sensor. The foreign object can be brought into contact with, or at least in close proximity to the surface to enter an instruction for controlling a device associated with the touch-sensitive input apparatus. A controller receives a signal indicative of a capacitance sensed by a first region included in the plurality of touch-sensing regions during application of a shield signal to a second region included in the plurality of touch-sensing regions. The second region is located adjacent to the first region.

Abstract: An apparatus is disclosed for monitoring brushes, such as slipring or commutator brushes, on electrical machines. At least one electronic sensor is configured to be arranged in or on a brush apparatus of an electrical machine. This sensor is measuring the brush position at high speed and high resolution, and characterized in that it receives a brush position signal from the brushes in a contact-less fashion. Data is collected by a central unit which sends the data to a server computer. Client computers can consult data, and real time monitor the status of the machine.

Abstract: A microwave sensor probe includes a probe housing, an emitter body coupled to the probe housing, and an emitter coupled to the emitter body. The emitter is configured to generate an electromagnetic field from at least one microwave signal. At least one electromagnetic absorbent member is configured to absorb at least one of a current transmitted through the emitter and an electromagnetic radiation generated by the emitter.

Abstract: A 4-port strip line cell for generating standard near fields includes an upper conductor, a third port, a first port, a lower conductor, a second port and a fourth port. The third port supplies a power signal to the upper conductor. The first port terminates the upper conductor. The lower conductor is disposed to be spaced apart from the upper conductor. The second port is connected to the lower conductor so as to supply a power signal in the opposite direction of the third port. The fourth port terminates the lower conductor.

Abstract: Wireless electronic devices include wireless communications circuitry such as transceiver circuitry coupled to an antenna resonating element. The transceiver circuitry and the antenna element may be formed on first and second substrates, respectively. In compact wireless devices, transceiver and antenna matching circuits may be formed on the first substrate. During production testing, a radio-frequency test probe with integrated matching circuitry may be used to mate with a corresponding contact point on the first substrate. The integrated matching circuitry may include resistors, capacitors, and inductors soldered in desired series-parallel configurations within the test probe. When the test probe is mated to the contact point on the first substrate, a test unit connected to the test probe may be used to perform radio-frequency measurements to determine whether the transceiver circuitry satisfies design criteria.

Abstract: A sensor head configured for use in a radio frequency operated sensing device, the sensor head comprising a non-planar antenna. The sensor head may further include means for connecting the sensor head to a data conduit. The non-planar antenna may be configured to have a predetermined resonance frequency within the radio frequency spectrum.

Abstract: An RF current probe is encapsulated in a conductive housing to permit its placement inside a plasma reactor chamber. An RF voltage probe is adapted to have a long coaxial cable to permit a measuring device to be connected remotely from the probe without distorting the voltage measurement.

Abstract: A method for position determination, having a first step, in which a first sequence of positions is determined from radio signals of stationary transmitters, and a second sequence of positions being determined from other sensor data by dead reckoning. The first sequence of positions and the second sequence of positions are compared with one another in a second step. A computer program product for carrying out the method is also provided. A position determining device, in particular in a mobile terminal is also provided, having a receiver for radio signals of stationary transmitters, having position determining means for determining a first position of the receiver from radio signals of stationary transmitters, sensors at least for determining a direction and a distance in order to determine a second position by dead reckoning, and a memory for storing a sequence of first positions and a sequence of second positions.

Abstract: The present disclosure relates to a measuring bearing currents in an electrical machine. According to exemplary embodiments, radio frequency signals that are generated by electric discharges are detected by an antenna near the bearing. A synchronizing signal is combined with the origin of the bearing current and signal triggered by the synchronizing signal is measured.

Abstract: A primary device for inductive power transfer to a secondary device is disclosed. The primary device includes a primary coil, the primary device being configured to (i) operate in a first mode during which the primary coil transfers power through inductive coupling to the secondary device, and (ii) operate in a second mode during which a foreign object is detected. The primary device further includes a primary controller configured to operate the primary coil (i) using a first frequency during the first mode, and (ii) using a second frequency during the second mode. A method to detect a foreign object which is in proximity of an inductively coupled environment of a primary device is also disclosed.

Abstract: A tunable proximity sensor and a method of manufacturing the same are disclosed. The proximity sensor includes a cap with different sections having different dielectric constants, shapes, and/or thicknesses. As the cap is rotated with respect the sensing element, these non-uniform sections induce a different loading on the sensor element from the electromagnetic field, allowing the proximity sensor to be tuned.

Abstract: An apparatus for ascertaining and monitoring a fill level and includes a transmitting/receiving unit and a delay circuit. The delay circuit includes at least a sampling clocking oscillator, which produces a sampling signal having a sampling frequency, a transmission clocking oscillator, which produces a pulse repetition signal having a pulse repetition frequency, and a frequency converter, which produces by means of sequential sampling a difference signal. The apparatus further includes a control/evaluation unit, which determines on the basis of travel time the fill level. Provided on the control/evaluation unit is an external clocking input, which is connected via a clocking line with a first clocking output of the sampling clocking oscillator or with a second clocking output of the transmission clocking oscillator. A stabilized and cost-favorable control circuit for producing an intermediate frequency signal with a highly accurately determinable, transformation factor results.

Abstract: Provided is a method and an apparatus for controlling an electric device. The apparatus includes a cabinet defining a recess, and a sensor disposed within said recess for sensing the presence of a foreign object in close proximity to the sensor. A veneer at least partially conceals the sensor disposed within said recess from view when observed from an ambient environment of the cabinet. A controller is responsive to a signal transmitted by the sensor indicative of the presence of the foreign object adjacent to the sensor to transmit a control signal for controlling operation of the electric device operatively connected to communicate with the controller.

Abstract: A system and method for soft-field tomography data acquisition are provided. One system includes a plurality of transducers that correspond to a plurality of channels, and an excitation driver coupled to generate excitation signals for the plurality of transducers. The system also includes a single reference excitation source from which excitations are generated and one or more derived excitation sources. The one or more derived excitation sources derive excitations from the single reference excitation source that are applied to each of the plurality of channels. The system further includes a response detector and a reduced bit digitizer in each of the plurality of channels configured to digitize a measured response difference between the measured response at one or more of the transducers and at least one of an excitation of the single reference excitation source or an excitation derived from the single reference excitation source or a separate reference.

Abstract: A wireless power transfer foreign object detector having, at least one secondary receiver coil, an adjustable load electrically coupled to the at least one secondary receiver coil, and at least one temperature sensor providing at least one temperature detection signal, wherein the at least one temperature sensor responsive to at least one thermal state of the at least one secondary receiver coil, and wherein foreign object detection is based at least in part upon the at least one temperature detection signal.

Abstract: A device (300) for the relative positioning of an electromagnetic probe network (100) and of an object being tested (200). The device includes at least a sliding element (301) to provide for the relative sliding of the object being tested (200) or of the electromagnetic probe network (100), to move the object being tested (200) or the probe network (100) along at least one sliding direction included in a plane of the probe network (100), and on which is provided a rotation device (320) for the relative rotation of the object being tested (200) and of the probe network (100) about a main rotation axis perpendicular to the sliding direction.

Abstract: An antenna loop layout method for an electromagnetic sensor board is provided. The electromagnetic sensor board has a plurality of inductive antennas which are arranged abreast of each other. One end of the inductive antennas is coupled to each other, and the other end of the inductive antennas have a switch. The method comprises the following steps: first, a pre-determined interval value is provided. Then, the switches are closed in sequence by the pre-determined interval value to form a plurality of physical antenna loops. The pre-determined interval value can be changed dynamically.

Abstract: This invention relates to a hybrid passive agent system impedance monitoring station and method. The method of monitoring impedance of an electrical system includes the steps of providing an impedance monitoring station adapted to test and monitor system impedance, solving for system impedance in a time domain, solving for system impedance in a frequency domain, and determining a time domain driving point impedance and a frequency domain driving point impedance to identify the impedance of the system.

Abstract: Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

Abstract: A method for manufacturing a measuring apparatus for capacitive determining and/or monitoring of at least the fill level of a medium. The measuring apparatus has a probe unit and an electronics unit. During a measurement, the electronics unit supplies the probe unit with an exciter signal and receives from the probe unit a received signal, from which the electronics unit ascertains a capacitance value. The probe unit is coated with an insulation layer, the coated probe unit is connected with the electronics unit and inserted into a container containing a calibration medium, the coated probe unit is covered completely by the calibration medium and an associated received signal is gained, and, with the associated received signal, at least one adjustable component of the electronics unit is set.

Abstract: A bi-directional bridge includes a forward bridge portion, and reverse bridge portion and a shared portion that enables the simultaneous measurement of power flowing in both directions while reducing insertion losses, providing better impedance matching and/or providing improved directionality. In some embodiments, additional attenuation is provided to reduce the common mode rejection requirements of detectors used with the bridge. In other embodiments, multi-tap attenuators and steering circuits may be integrated into the forward and/or reverse bridge portions to reduce common mode signal levels while still maintaining high levels of sensitivity for measuring small input signals.

Abstract: A sensor device is provided, with a first electrode structure and a second electrode structure, wherein the first electrode structure has a transmitting electrode, a compensation electrode and a reception electrode and wherein the second electrode structure has a number of field sensing electrodes. The first and the second electrode structure are coupled with an evaluating device. The evaluating device has a signal generator for supplying the transmitting electrode and the compensation electrode with an alternating electrical signal. The reception electrode, the transmitting electrode, the compensation electrode and the field sensing electrodes are arranged in relation to each other in such a way that a first alternating electrical field emitted at the transmitting electrode may be coupled into the reception electrode and into one of the field sensing electrodes and a second alternating electrical field emitted at the compensation electrode may be coupled substantially only into the reception electrode.

Abstract: The invention relates to a shielded double-coil multilayer assembly intended to be used in an inductive detector. This multilayer assembly comprises a plurality of stacked parallel separated layers, namely: a layer (C1) comprising a first shielding element for a first coil, a layer (C2) comprising all or part of a first coil, a layer (C3) comprising all or part of a second coil, a layer (C4) comprising a first shielding element for the second coil.

Abstract: A sensor for sensing proximity or touch of an object includes a sensing region, an oscillating signal generator for generating an oscillating signal having an oscillation period, a gating signal generator for generating a gating signal having a gating duration, a controller for controlling the oscillation period or the gating duration and a processor for determining a number N of oscillation periods over the gating duration. The number N is indicative of the object's contact with, or proximity to, the sensing region. The sensor is calibrated by determining an optimal value for the oscillation period or gating duration such that an optimal number N over the gating duration is expected.

Abstract: An antenna system for electromagnetic compliance testing within a frequency range includes a driven element mounted on a boom and including opposed first and second length-adjustable conductors. A length-adjustable passive element is mounted on the boom and spaced apart from the driven element and including opposed third and fourth length-adjustable conductors. An RF input connector is coupled between a feed path to a feed end of each length-adjustable conductors in the driven element. The feed path is configured to minimize stray reactances and stub effects within the frequency range.

Abstract: A wireless in-plane strain and displacement sensor includes an electrical conductor fixedly coupled to a substrate subject to strain conditions. The electrical conductor is shaped between its ends for storage of an electric field and a magnetic field, and remains electrically unconnected to define an unconnected open-circuit having inductance and capacitance. In the presence of a time-varying magnetic field, the electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses. The sensor also includes at least one electrically unconnected electrode having an end and a free portion extending from the end thereof. The end of each electrode is fixedly coupled to the substrate and the free portion thereof remains unencumbered and spaced apart from a portion of the electrical conductor so-shaped. More specifically, at least some of the free portion is disposed at a location lying within the magnetic field response generated by the electrical conductor.

Abstract: A system has a battery serving as a DC voltage source for electrical equipment of the system, a sensor for sensing an electric field (e-field) generated by the DC voltage source, sensor signal processing circuitry connected to the sensor for receiving a sensor output signal therefrom, and an e-field indicating device coupled to the sensor signal processing circuitry for receiving a processed DC e-field signal therefrom. The sensor outputs the sensor output signal, which is dependent upon a distance between the sensor and the DC voltage source. The sensor signal processing circuitry derives a processed direct current (DC) e-field signal from the sensor output signal. The e-field indicating device outputs the e-field indicating signal in response to the processed DC e-field signal indicating that the e-field exceeds an e-field threshold level.

Abstract: Embodiments include methods and apparatus for characterizing a tuner. For a given tuner, a processing system is adapted to measure scattering parameters for a plurality of characterization points that are non-uniformly distributed across a Smith chart, and to store the scattering parameters in a tuner characterization file. Interpolation and extrapolation processes are performed to determine additional scattering parameters for a plurality of additional characterization points, which are also stored in the tuner characterization file.

Abstract: An electronic circuit with a plurality of connections for a plurality of sensor elements is provided, wherein the electronic circuit is configured to detect, with at least one multiplexing method, the presence of an object in at least one observation area of the sensor elements and to distinguish between the sensor elements. Also a method for determining the position of at least one object situated in at least one observation area of sensor elements relative to the sensor elements is provided, whereby with a multiplexing method an electric variable for each sensor element is detected, which is indicative for the presence of the object in the respective observation area.

Abstract: An antenna loop layout method for an electromagnetic sensor board is provided. The electromagnetic sensor board has a plurality of inductive antennas which are arranged abreast of each other. One end of the inductive antennas is coupled to each other, and the other end of the inductive antennas have a switch. The method comprises the following steps: first, a pre-determined interval value is provided. Then, the switches are closed in sequence by the pre-determined interval value to form a plurality of physical antenna loops. The pre-determined interval value can be changed dynamically.

Abstract: Wireless electronic devices include wireless communications circuitry such as transceiver circuitry coupled to an antenna resonating element. The transceiver circuitry and the antenna element may be formed on first and second substrates, respectively. In compact wireless devices, transceiver and antenna matching circuits may be formed on the first substrate. During production testing, a radio-frequency test probe with integrated matching circuitry may be used to mate with a corresponding contact point on the first substrate. The integrated matching circuitry may include resistors, capacitors, and inductors soldered in desired series-parallel configurations within the test probe. When the test probe is mated to the contact point on the first substrate, a test unit connected to the test probe may be used to perform radio-frequency measurements to determine whether the transceiver circuitry satisfies design criteria.

Abstract: Methods and systems are provided for determining the surface electromagnetic impedance of a conductive element and applying the diffuse field reciprocity principle using that surface electromagnetic impedance to determine electric fields induced in the conductive element. An exemplary method involves determining a surface electromagnetic impedance matrix for the conductive element based on its physical dimensions and an excitation frequency for an incident electromagnetic wavefield, applying diffuse field reciprocity to determine a metric indicative of an induced field based on the surface electromagnetic impedance matrix and an energy metric for the incident electromagnetic wavefield, and displaying a graphical representation of the metric on a display device.

Abstract: A system and method for soft-field tomography data acquisition are provided. One system includes a plurality of transducers that correspond to a plurality of channels, and an excitation driver coupled to generate excitation signals for the plurality of transducers. The system also includes a single reference excitation source from which excitations are generated and one or more derived excitation sources. The one or more derived excitation sources derive excitations from the single reference excitation source that are applied to each of the plurality of channels. The system further includes a response detector and a reduced bit digitizer in each of the plurality of channels configured to digitize a measured response difference between the measured response at one or more of the transducers and at least one of an excitation of the single reference excitation source or an excitation derived from the single reference excitation source or a separate reference.