Abstract: A method for determining a phase constant for a dielectric medium is provided. The method includes deploying a calibration object with a known free-space spectral response within a dielectric medium of interest, determining the spectral response of the calibration object deployed in the dielectric medium, and determining the phase constant for the dielectric medium using a relationship between the free-space spectral response of the calibration object and the spectral response of the calibration object when deployed in the dielectric medium.

Abstract: A method for impedance measurements, using synchronous detecting and modified rectangular signals. The method comprises introducing a first modified rectangular signal into a bioobject, receiving a response signal from said bioobject, introducing said response signal and a second modified rectangular signal into a synchronous detector, whereas either one or both rectangular signals are modified to remove particular higher harmonics from the signal. In one embodiment, either one or both the first and the second modified rectangular signals are generated by summing at least two modified rectangular signals, wherein at least one of such rectangular signals have a zero amplitude segment introduced between rectangular half periods.

Abstract: A system and method to detect changes in composite structures using RF signal pattern data interpretation. An RF signal is transmitted from a composite material manufactured structure and a plurality of sensors are employed to measure the RF signal. The measured RF signal is compared to a stored baseline RF signal for the particular structure. Deviations in the measured RF pattern for the structure, or for a structurally-similar composite structure, are automatically analyzed to detect non-visually-detectable defects or other changes in the composite structure. A baseline RF signature is developed for a structure by transmitting a reference RF signal from the composite structure. RF signals are detected by a variety of methods, and the detected signals are compiled and translated into reference and/or test RF signal patterns for the structure.

Abstract: A method for measuring electric circuit parameters of a 2-terminal circuit having first and second terminals, includes steps of: terminating one of the first and second terminals with a terminal impedance Z1, to measure reflection characteristics ?1 for the other terminal; terminating one of the first and second terminals with a terminal impedance Z2 different from the terminal impedance Z1, to measure reflection characteristics ?2 for the other terminal; terminating one of the first and second terminals with a terminal impedance Z3 different from the terminal impedances Z1 and Z2, to measure reflection characteristics ?3 for the other terminal; and calculating electric circuit parameters of the 2-terminal circuit based on the resultant reflection characteristics ?1, ?2 and ?3, whereby measuring electric circuit parameters, such as S-parameters, Z-parameters or the like, even of a DUT having a weak ground, in a simple way with high accuracy and low cost.

Abstract: An AC impedance measurement system is used for measuring the impedance of a DUT. A measured voltage is applied to a first DUT terminal by a first digital to analog converter, the voltage appearing at the second terminal of the DUT is monitored through an analog to digital converter and forced by a second digital to analog converter to a desired negligible value, and a digital controller determines the impedance of the DUT from the measured voltage and the current necessary to force the voltage appearing at the second terminal to the desired negligible value.

Abstract: A method for identifying a drifted dose integrator in an implantation system and an implantation system are provided. The implantation system includes a first dose integrator and a second dose integrator. The first dose integrator includes a first input configured to receive a first current generated from charges carried by implanted ions in a wafer, and a first output configured to output a first accumulated dosage value. The second dose integrator includes a second dose integrator including a second input configured to receive a second current generated from the charges carried by the implanted ions in the wafer, and a second output configured to output a second accumulated dosage value. The implantation system further includes a processing unit comparing the first accumulated dosage value and the second accumulated dosage value to detect a drift in one of the first and the second dose integrators.

Abstract: The invention is directed to a spectrometer for measuring submillimeter absorption. The spectrometer may include a solid state exciter generating a submillimeter wave and sweeping a predetermined frequency band, a frequency marker generating unit electrically generating frequency markers, a sample cell to contain a gas, and a solid-state detector detecting a submillimeter absorption of the gas. A spectrometer energizes a solid-state oscillator to generate a submillimeter wave and to sweep a predetermined band of frequency. The submillimeter wave is introduced into a sample cell containing a gas and frequency markers that are electrically generated during the sweep. Outputs of a solid-state detector disposed in the sample cell are read and recorded as a function of time and with the frequency markers. The recorded outputs of the solid-state detector are converted into a function of frequency using the recorded frequency markers.

Abstract: An apparatus (2) for measuring electrical conductivity in a material comprises a pair of electrically conducting elements (6), a first electrical conductor (9) coupled to the electrically conducting elements, the first electrical conductor coupling a first transformer core (10) and a second transformer core (12) to form a first current loop (8) and a second electrical conductor (17) of known resistance coupling the second transformer core and a third transformer core (14) to form a second current loop (16).

Abstract: An exemplary method comprises the steps of introducing a reactive current reference square wave, detecting load voltage changes at every change in the reactive current reverence wave, and determining whether the detected load voltage changes exceed a predefined islanding detection threshold value, indicating a loss of mains and an islanding operation of the power generator. With the exemplary loss-of-mains detection, islanding can be detected within a shortest period of time, even if the local islands active and reactive load matches exactly the distributed generators active and reactive power generation. So even without a sudden voltage change, unintentional islanding can immediately be detected and control electronics can safely turn of the distributed power generator.

Abstract: The failure detecting apparatus includes an input circuit 13 connected to a temperature sensor 53 to detect various changes, for detecting the resistance of the temperature sensor 53, a monitor circuit 14 connected in parallel to the input circuit 13 for monitoring the failure of the input circuit 13, and a CPU 1 which is supplied with the resistance of the temperature sensor 53 detected by the input circuit 13 and in detecting failure of the monitor circuit 14, switches its state between the inputting state receiving a signal from the monitor circuit 14 and the outputting state sending the signal to the monitor circuit 14.

Abstract: A directional bridge for measuring propagated signals to and from a source device to a load device where both the source device and load device are in signal communication with the directional bridge is disclosed. The directional bridge may include a first bridge circuit network and a first sensing element in signal communication with the first bridge circuit network. The first sensing element may produce a first measured signal that is proportional to the propagated signals.

Abstract: A differential signaling system is provided. The differential signaling system comprises one or more cable pairs for carrying signals, one or more differential drivers for providing signals to the one or more cable pairs, and one or more differential receivers, the one or more differential receivers being coupled to the one or more differential drivers via the one or more cable pairs. The differential signaling system further comprises one or more test devices for testing the differential signaling system, and at least one switch coupled to at least one of the one or more cable pairs and to at least one of the one or more test devices, the switch being adapted to dynamically switch the at least one of the one or more test devices into a differential interface of the differential signaling system.

Abstract: A technique for testing an electronics assembly for a power short circuit is provided. The technique includes pre-characterizing power off resistance of an electronic component(s) of a first packaging level from at least one power boundary of the electronic component(s). The characterizing of the power off resistance occurs prior to placement of the electronic component(s) into an electronics assembly of a higher packaging level. The technique further includes determining actual power off resistance of the electronics component(s) after placement thereof into the electronics assembly, with the actual power off resistance being determined from the at least one power boundary. Thereafter, the actual power off resistance of the electronic component(s) in the electronics assembly is compared with the pre-characterized power off resistance of the at least one electronic component(s), and a determination is made therefrom whether a power short circuit exists within the electronics assembly.

Abstract: There is provided a differential comparator circuit that is mounted on a test apparatus for testing a device under test outputting differential signals including noninverted signals and inverted signals. The differential comparator circuit includes: a difference signal subtracting circuit operable to compute and output a difference signal indicative of a difference between the noninverted signal and the inverted signal; a first threshold value subtracting circuit operable to compute and output a first threshold voltage indicative of a difference between a first comparative voltage generated based on ground potential of the device under test and a reference voltage generated based on the ground potential of the device under test; and a first comparing circuit operable to compare the difference signal and the first threshold voltage to output a comparison result.

Abstract: A sensor for detecting contact of a fluid delivery probe with a fluid surface and for detecting fluid flow through the probe includes a first electrode disposed along a fluid flow path of the probe upstream from a distal tip of the probe and a second electrode longitudinally spaced and electrically isolated from the first electrode and disposed at the distal tip of the probe. An oscillating signal is transmitted through the first electrode, and at least a portion of the signal is received through the second electrode. Through changes in the received signal due to the distal tip of the probe coming into contact with a fluid surface or due to fluid flow through the conduit between the first and second electrodes, fluid surface contact and fluid flow can be detected. A pressure sensor can be employed to monitor internal fluid pressure within the fluid conduit of the fluid delivery probe as a secondary, redundant mechanism for detecting fluid flow through the conduit.

Abstract: A sensor for detecting contact of a fluid delivery probe with a fluid surface and for detecting fluid flow through the probe includes a first electrode disposed along a fluid flow path of the probe upstream from a distal tip of the probe and a second electrode longitudinally spaced and electrically isolated from the first electrode and disposed at the distal tip of the probe. An oscillating signal is transmitted through the first electrode, and at least a portion of the signal is received through the second electrode. Through changes in the received signal due to the distal tip of the probe coming into contact with a fluid surface or due to fluid flow through the conduit between the first and second electrodes, fluid surface contact and fluid flow can be detected. A pressure sensor can be employed to monitor internal fluid pressure within the fluid conduit of the fluid delivery probe as a secondary, redundant mechanism for detecting fluid flow through the conduit.

Abstract: According to some embodiments, time domain reflectometry based transmitter equalization is provided. For example, a reflection detector in a transmitter may detect a reflection signal associated with a calibration signal that was transmitted via an interconnect. The reflection detector may then provide filter information to a transmitting unit to facilitate a transmission of data to a remote receiver via the interconnect. According to some embodiments, the receiver adjusts a termination impedance before the calibration signal is transmitted.

Abstract: A device for the comparison of two resistors is based upon analog information carried by currents. The device includes a measurement circuit for extracting the currents from the two resistors to be compared, and copies the currents to a parallel analog-digital converter that carries out the division of the extracted currents. The device converts the ratio of the extracted currents into a digital code that is the image of the ratio of the two resistors. The ratio is constantly re-updated as a function of environmental parameters of the circuit, such as the operating temperature. Also disclosed is a system for correcting the value of integrated compensated resistors. The system implements a device of this kind that does not use a reference voltage generator.

Abstract: An improved system for determining the value of a resistive load is provided. The system includes: a reference voltage source; a reference resistor of known value having a first and second terminal, the first terminal connected to the reference voltage source and the second terminal connected to the resistive load; and a software program stored in a control unit connected to the first and second terminal, the control unit operative to read a value of the reference voltage source and a voltage at the second terminal of the predetermined reference resistor and to calculate the value of the resistive load as a function of the readings of the reference voltage source and the second terminal voltages.

Abstract: A comparison circuit for comparing the desired voltage levels of electronic components and for disabling the supply of power to those components if the desired voltage levels are not equivalent. The comparison circuit receives the desired voltage level indication signals and provides a signal indicating whether the desired voltage levels are equivalent. If the desired voltage levels are not equivalent, the comparison circuit provides a signal indicating non equivalency to a power supply, wherein the power supply is disabled from supplying power so as not to damage the computer components from receiving power at a non allowable voltage level. The comparison circuit also provides an output signal indicative of an equivalent voltage level to the desired voltage levels if the desired voltage levels are equivalent. A power supply converter supplies power to the components at a voltage level as indicated by the output signal.

Abstract: Systems, methods, and probe devices for electronic monitoring and characterization using absorbent media confined by a metallic mesh. The mesh allows a stream of liquid or gas to pass through the structure, so that the media will adsorb the material to which it is specific. This changes the permittivity of the media in which the electromagnetic field is propagating. This change in permittivity can be seen through the use of classical microwave methods such as phase shift, amplitude changes, frequency changes in a cavity or the frequency of an unbuffered oscillator. Some embodiments use a two cylinder structure, where an outer cylinder contains a material which selectively removes a chemical which may be in conflict with or would contaminate the sensing of the desired chemical. This outer cylinder does not play a part in the measurement because it is outside the metal shield which contains the measurement adsorbent, and is thus outside the electromagnetic field.

Abstract: Determinations are made related to the presence of a predetermined material in concrete under test using previously obtained model information. In one embodiment, the predetermined material includes a chloride material and the model information is obtained using a number of cured cement specimens. The model information is stored in memory, such as in the form of a look-up table. When the concrete is being inspected, one or more magnitudes of reflections coefficients are measured and such is utilized with the model information to make determinations related to the presence of the predetermined material. In developing the model information, each of the plurality of cured cement specimens is located in a bath containing the predetermined material. The bath may be pressurized. The cured cement specimens are maintained in the bath for different, known time intervals. After the known time interval for a particular specimen, it is dried and one or more magnitudes of reflection coefficients are measured.

Abstract: A sensor for detecting contact of a fluid delivery probe with a fluid surface and for detecting fluid flow through the probe includes a first electrode disposed along a fluid flow path of the probe upstream from a distal tip of the probe and a second electrode longitudinally spaced and electrically isolated from the first electrode and disposed at the distal tip of the probe. An oscillating signal is transmitted through the first electrode, and at least a portion of the signal is received through the second electrode. Through changes in the received signal due to the distal tip of the probe coming into contact with a fluid surface or due to fluid flow through the conduit between the first and second electrodes, fluid surface contact and fluid flow can be detected. A pressure sensor can be employed to monitor internal fluid pressure within the fluid conduit of the fluid delivery probe as a secondary, redundant mechanism for detecting fluid flow through the conduit.

Abstract: A method and system for measuring at least one of a plasma density and an electron density (e.g., in a range of 1010 to 1012 electrons/cm−3) using plasma induced changes in the frequency of a microwave oscillator. Measurement of at least one of the plasma density and the electron density enables plasma-assisted processes, such as depositions or etches, to be controlled using a feedback control. Both the measurement method and system generate a control voltage that in turn controls a plasma generator to maintain at least one of the plasma density and the electron density at a pre-selected value.

Abstract: A system and method for monitoring the conditions in a gas plasma processing system while varying or modulating the RF power supplied to the system, so that resulting signals of the electrical circuits of the system provide information regarding operational parameters of the system or the state of a process. Significant improvements in sensitivity and accuracy over conventional techniques are thereby achieved. In addition, the plasma processing system can be thoroughly tested and characterized before delivery, to allow more accurate monitoring of and greater control over a process, thereby improving quality control/assurance of substrates being produced by the system. The information obtained by the modulation technique can be displayed on a monitor screen, in order to allow an operator to accurately monitor the system/process and diagnose any problems with the system/process.

Abstract: A contactor includes a switching circuit for switching a load between one or more electrical supplies, a current detector for detecting the current flowing through the load, a trip circuit for tripping the current after an interval of time which depends upon how much the current flowing through the load exceeds a predetermined amount, and a pre-trip circuit for providing an indication during said time interval that the current exceeds said predetermined amount for providing ‘pre-trip’ or ‘near-trip’ information.

Abstract: A voltage measurement apparatus is provided for measuring a voltage of each of N power sources connected in series. The apparatus includes N capacitance elements provided respectively corresponding to the N power sources, and connected in series, a first switching section for simultaneously applying a voltage of each power source to one of the N capacitance elements corresponding to said power source, a voltage measurement section for measuring a voltage of each capacitance element, and a second switching section for sequentially connecting each capacitance element to the voltage measurement section.

Abstract: In a light receiving circuit for use in electro-optic sampling oscilloscope which receives first and second optical, photodiodes 51 and 52 are connected in series between a positive bias power supply 50P and a negative bias power supply 50N. The photodiodes 51 and 52 receive optical signals whose polarization state correspond to the voltage of a signal to be measured and convert the thus-received optical signals into electric signals. An amplifier 53 amplifies an electric current appearing in a point of connection P between the photodiodes 51 and 52. A current monitor 54 detects the electric signal converted by the photodiode 51, and a current monitor 57 detects the electric signal converted by the photodiode 52. The electric signal detected by the current monitor 54 is subjected to analog-to-digital conversion by an analog-to-digital converter 55, and the electric signal detected by the current monitor 57 is subjected to analog-to-digital conversion by an analog-to-digital converter 58.

Abstract: A transmission line for carrying digital signals is provided with auxiliary line drivers at the receiver end, which are used in combination with the data line driver at the transmitting end to apply a sequence of sets of test voltages onto the line. The voltage resulting at the receiver input is used to detect open signal conductors and/or shorts in the receiver.

Abstract: A system and method for monitoring the conditions in a gas plasma processing system while varying or modulating the RF power supplied to the system, so that resulting signals of the electrical circuits of the system provide information regarding operational parameters of the system or the state of a process. Significant improvements in sensitivity and accuracy over conventional techniques are thereby achieved. In addition, the plasma processing system can be thoroughly tested and characterized before delivery, to allow more accurate monitoring of and greater control over a process, thereby improving quality control/assurance of substrates being produced by the system. The information obtained by the modulation technique can be displayed on a monitor screen, in order to allow an operator to accurately monitor the system/process and diagnose any problems with the system/process.

Abstract: A method and a communications device are described, comprising a radio telephone (5) with connected antenna path (1) which can be used to locate precisely a defective area (F) in the antenna path (1) in order to be able to repair the antenna path (1) in a selective fashion. For this purpose, initially a wave with a starting frequency (f0) is coupled into the antenna path (1), and the amplitude of the standing wave at an angular position is measured. Then, the frequency of the wave is increased until a corresponding amplitude is detected at the same angular position. From the frequencies present then and from a reading (n) which indicates how often the corresponding amplitude has been obtained, the fault interval (Ed) between the detector (18) and defective area (F) is then calculated.

Abstract: An output power detection circuit of a transmitter, which can accurately detect a power outputted from a power amplifier without depending on a change in ambient temperature is realized. The circuit comprises: a first diode to which a first bias direct current is applied; first load resistors through which the first bias direct current flows; a second diode to which a second bias direct current is applied; second load resistors through which the second bias direct current flows; and a differential amplifier. A first voltage generated in the first load resistor and a second voltage generated in the second load resistor are made substantially the same and are applied to the differential amplifier, a detection voltage obtained by detecting operation of the first diode is added to the first voltage, and a voltage corresponding to the power generated from a power amplifier is detected.

Abstract: A sensor for detecting contact of a fluid delivery probe with a fluid surface and for detecting fluid flow through the probe includes a first electrode disposed along a fluid flow path of the probe upstream from a distal tip of the probe and a second electrode longitudinally spaced and electrically isolated from the first electrode and disposed at the distal tip of the probe. An oscillating signal is transmitted through the first electrode, and at least a portion of the signal is received through the second electrode. Through changes in the received signal due to the distal tip of the probe coming into contact with a fluid surface or due to fluid flow through the conduit between the first and second electrodes, fluid surface contact and fluid flow can be detected. A pressure sensor can be employed to monitor internal fluid pressure within the fluid conduit of the fluid delivery probe as a secondary, redundant means for detecting fluid flow through the conduit.

Abstract: A process and apparatus are provided to determine the characteristic impedance of a transmission line coupled to the output of a buffer. To achieve this, an output resistance of the buffer is initially set to a relatively high value to underdrive the transmission line. The output resistance of the buffer is then decreased until the buffer overdrives the transmission line. The characteristic impedance of the transmission line can then be determined from a ringback voltage which occurs due to the overdriving of the transmission line. In accordance with an embodiment of the invention, the ringback voltage can be detected by noting when a reference voltage is crossed twice during the same time of the driving pulse on the transmission line (the second crossing being the ringback voltage). The characteristic impedance of the transmission line can then be used to set the output resistance for the buffers on the operational buses.

Abstract: Time Domain Reflectometry ("TDR") methods and apparatus for measuring propagation velocities of RF pulses to determine material liquid contents, moisture profiles, material levels and dielectric constants including: i) TDR probes and/or probe adaptors, including series averaging probes and multi-segment probes, all employing remotely operable, normally open, variable impedance devices such as diodes; ii) bias insertion and switching networks for rendering selected normally open variable impedance devices conductive one at a time to establish precise unambiguous timing markers T.sub.1 . . . T.sub.

Abstract: An apparatus is disclosed for testing concrete having an unknown water/cement ratio and an unknown compressive strength. The apparatus includes a transmitter assembly for transmitting microwave signals at one or more predetermined frequencies. A receiver assembly receives each microwave signal reflected from the concrete under test. The reflected microwave signals, together with the transmitted microwave signals, are used to determine a reflection coefficient magnitude for the particular microwave frequency. A processing unit uses the reflection coefficient magnitude to determine a value related to concrete strength. In one embodiment, the processing unit relies on a logarithmic function that correlates the reflection coefficient magnitude and a water/cement ratio. A value related to the compressive strength of the concrete can also be obtained using the value of the water/cement ratio or the value of the reflection coefficient magnitude.

Abstract: An instrument for measuring the dielectric constant of samples with complex or uncertain geometries that can include unusually shaped single sample pieces or collections of differently shaped sample pieces such as powders. The premise of the measurement technique is that a reference capacitor plate and a sample capacitor plate are exposed to a dynamically-changing solvent mixture. When the capacitance of these two fixtures become equal at the point at which a particular solvent mixture is reached, the dielectric constant of the sample is then known.

Abstract: Time Domain Reflectometry ("TDR") methods and apparatus for measuring propagation velocities of RF pulses to determine material liquid contents, moisture profiles, material levels and dielectric constants including: i) TDR probes and/or probe adaptors, including series averaging probes and multi-segment probes, all employing remotely operable, normally open, variable impedance devices such as diodes; ii) bias insertion and switching networks for rendering selected normally open variable impedance devices conductive one at a time to establish precise unambiguous timing markers T.sub.1 . . . T.sub.

Abstract: A method and apparatus for detecting grain direction in wood by means of microwave radiation. A sample of timber is exposed to a polarized microwave beam emitted by a transmitter (11). A polarized receiver (12) evaluates the microwave energy that has been affected by the timber. The receiver and transmitter polarization planes are locked at either 0 or 90 degrees respect to each other. Both are rotated synchronously and the received energy is plotted versus angle. The energy maximum or minimum gives indication of the grain direction in the timber sample under evaluation.

Abstract: A multipath component detector detects the correlation between a received signal and a reference signal in a training period of the received signal and estimates and outputs the multipath received component levels at a plurality of timing points. A component ratio calculator calculates the ratio of each received component to the overall received power. By this, the level ratio of a specified received component can be detected. Power dissipation can be minimized by switching the detector to a differential detector or an adaptive equalizer in accordance with the result of the delay spread measurement.

Abstract: A flexible and efficient integrated circuit chip that includes pad drivers for driving an impedance of a transmission line, wherein the integrated circuit further includes all additional circuitry to automatically adjust a matching impedance of the pad drivers. The integrated circuit chip includes a set of selectively activatable pad drivers and a counter coupled with the drivers for selectively activating an initial number of members of the set of the pad drivers to drive the transmission line with a test pulse. The integrated circuit chip further includes a comparator having a first input for sensing a voltage amplitude of the test pulse and a second input coupled with a voltage reference for comparing the voltage amplitude of the test pulse with the reference voltage. An output of the comparator is coupled with the counter for increasing the counter's initial number of selected members of the set of the pad drivers if the voltage amplitude of the test pulse is less than the reference voltage.

Abstract: Apparatus which determines the water cut of a sample petroleum stream irradiates the sample stream at two different locations with microwave energy. The distance that the microwave energies pass through the sample stream are also different. A receiver receives the microwave energies and provides corresponding received signals. The water cut is determined in accordance with the received signals.

Abstract: For extending the dynamic range in measurements carried out with a directional coupler, such as antenna measurements, a signal is supplied to the object under analysis, such as an antenna, through a first port of the measuring directional coupler, part of the signal leaking as a leak signal through a second port of the measuring directional coupler directly towards a measuring device. The signal returning from the object under analysis is measured by the measuring device. To enable the measuring of signal levels lower than before, spurious signals, such as the leak signal, summing to the signal to be measured are eliminated by supplying a phased compensation signal through a second directional coupler to the measuring line.

Abstract: A method for completely characterizing coupled transmission lines by short-pulse propagation is described. The complex frequency-dependent propagation matrix, impedance matrix and admittance matrix for a set of n parallel transmission lines can be determined by comparing the properties of two sets of coupled transmission lines of different length. Each transmission line set has two conductors of unequal length and ground conductors to form a coupled transmission line system. Each transmission line set can have uncoupled ends. An input pulse is provided at at least one node of each transmission line set. The complex frequency dependent propagation matrix of each transmission line set is determined by a comparison of the output pulses at the remaining nodes of each transmission line set which involves ratioing to cancel out the effect of the pad-to-probe discontinuity and the uncoupled ends which make it unnecessary to do any embedding.

Abstract: An apparatus and a method for the measurement of the complex dielectric constant of a material by evaluating the amount of detuning introduced by the presence of the material. In order to simplify the circuitry required for measurement and evaluation according to the invention there are provided two rf resonators (8, 8') of the same construction, each of them comprising a dielectric solid state resonator (1, 1') in a case having a first conductive section (2, 2') and a second section (3, 3'), which is permeable for alternating fields. Both the rf resonators are positioned to each other in such a way as to provide a shielding effect by their conductive case sections (2, 2') against mutual interference and to have their sections permeable for electromagnetic fields (3, 3') facing towards the material to be measured.

Abstract: A sensor and method for identifying the surface properties of a workpiece includes a microstrip sensor for transmitting and receiving microwave signals and surface properties determining means for determining the surface properties of the workpiece, including the type of material from which the workpiece is constructed, based upon the strength of the detected microwave signals. The surface properties identifying sensor also includes a microwave generator for producing microwave signals at a predetermined frequency for transmission by the microstrip sensor and a detector for detecting the microwave signals received by the microstrip sensor from the workpiece. Thus, workpieces comprised of a conductive material, an insulative material and a conductive material coated with a radar absorbing material can be readily distinguished by the surface properties identifying sensor and method.

Abstract: A surface condition sensing system includes a frequency controlled source of electromagnetic power adapted to produce a band of selected frequencies which are directed to a surface under examination. A monitoring circuit compares transmitted and reflected electromagnetic power as a function of frequency from the surface, and generates a plurality of absorption signals representing the difference between the amplitude of the transmitted signal with the corresponding amplitude of the reflected signal. An evaluator circuit generates a surface condition signal representing the results of a comparison between the plurality of absorption signals with known surface models. A control circuit generates a status signal representative of the surface condition. The system can be configured as a road condition sensor or as an aircraft ice detection sensor.

Abstract: Time Domain Reflectometry ("TDR") methods and apparatus for measuring propagation velocities of RF pulses to determine material liquid contents, moisture profiles, material levels and dielectric constants including: i) TDR probes and/or probe adaptors, including series averaging probes and multi-segment probes, all employing remotely operable, normally open, variable impedance devices such as diodes; ii) bias insertion and switching networks for rendering selected normally open variable impedance devices conductive one at a time to establish precise unambiguous timing markers T.sub.1 . . . T.sub.

Abstract: The means and method of the present invention includes a source of microwave energy and associated elements which provide microwave energy to a petroleum stream. Other circuitry include elements which receive microwave energy from the petroleum stream. Electronic apparatus provides at least one outputs utilizing the provided microwave energy, the received microwave energy and known values for 100 percent oil, percent surfactant and 100 percent water, corresponding to a ratio of surfactant to oil/water mixture.

Abstract: An apparatus and method to measure the unburnt carbon content of fly ash. A microwave signal is transmitted through or reflected from a fly ash sample and the attenuation or phase shift of the signal received by a detector/detectors is determined with respect to the incident signal and is used to provide a measure of unburnt carbon content. The detectors may be antennae means which also launch the incident signal or may be a completely separate means. A preferred embodiment comprises a microwave oscillator for launching the microwave signal into a fly ash sample in a microwave resonant cavity. Detectors determine the attenuation of phase shift of the received signal with respect to a signal from a reference microwave resonant cavity by the fly ash sample, and a measurement of the unburnt carbon content is obtained.