Abstract: Radio-wave propagation is rapidly predicted by a hybrid computational method that uses Ray Optics techniques to calculate radio field strength above a limiting radio-wave ray, Parabolic Equation techniques to calculate radio field strength below the limiting radio-wave ray and below a predetermined altitude, and a newly created Extended Optics method to compute radio field strength in an area of the atmosphere below the limiting radio-wave ray and above the predetermined altitude. Rays in the extended optics area are initialized from the elevation angle that rays traced through the parabolic equation area make with the predetermined altitude. Where reflected, direct or origin created rays do not exist within the parabolic equation area, the elevation angle for the ray that does exist at the furthest range (optical limit) is used to initiate ray tracing in the extended optics area for ranges beyond the optical limit.

Abstract: A watt-hour meter cover is provided which has an optical coupler including a conduit, lens, and means for engaging an external programmer/reader. The conduit is has improved signal transmission properties. The cover may be designed to disable test mode hardware when replaced after meter servicing. A battery access hatch and module with a reset and scroll actuator is installed through the cover.

Abstract: An optical transformer designed to equip a grounded metal-clad installation, wherein the transformer includes a disk which is disposed transversely to the axis of the cladding and which is provided with openings via which the conductors pass, optical fibers being disposed at the periphery of said openings and being connected to an associated optical interface placed outside the cladding.

Abstract: A method and system is disclosed for indication and prevention of tampering with an electricity meter having control circuitry for automatic remote reading. The control circuitry, provided externally of the meter in a base or base extension, to which the meter is connected, is also used for tamper detection. Embodiments of the invention include use of optical sensing, voltage detection and proximity detection. Ambient light sensing may be performed to detect separation of the meter from the external receptacle. Reflected light to a reflective surface of the meter is sensed to determine if the meter is properly engaged. Presence of a meter connection plug element may be sensed either optically or by position responsive switch. Voltage of the utility supply and meter user output may be monitored to determine tampering.

Abstract: A light source for emitting a pulsed laser beam having an ultrashort pulse width and a voltage detector including the light source therein. The light source includes a laser driving unit for driving the laser source to output the pulsed laser beam while the intensity of the pulsed laser beam is stabilized. A chirp compensator is also included to compensate for a chirp in the pulsed laser beam. A wavelength selector is used to extract light having a desired wavelength from the pulsed laser beam, thereby obtaining a pulsed laser beam having an ultrashort pulse width and a desired narrow spectral band width.

Abstract: A process and a system for measuring the temporal course of a recurring signal at at least one site of, measurement of a sample, the sample being impinged upon by a primary corpuscular beam and a secondary signal being derived from the sample. The process and the system has a primary beam current that is temporally variable. There is interaction between the primary beam and the sample. At least one part of the interaction between the primary beam and the sample is registered and/or recorded. The temporal relationship between a trigger signal, which is in a defined temporal relationship with the signal course to be measured, and the course of the primary wave current is measured. The registered and/or recorded values of the secondary signals are assigned to the points in time of the signal course to be measured according to the temporal relationship measured in the preceding step of the process.

Abstract: A method and apparatus for sensing electric and electromagnetic fields incorporating a fiber-optic transducer which mounts directly on a conventional optical fiber waveguide. The transducer employs a conductive Fabry-Perot microcavity bounded by a conductive, thin and corrugated diaphragm. When the conductive microcavity is placed in an electric field, the electric field is excluded from within the equipotential microcavity and a net electrostatic force acts on the diaphragm. Likewise, when the conductive microcavity is exposed to an electromagnetic wave, the wave exerts a radiation pressure on the diaphragm. In both cases, the diaphragm deflects linearly and uniformly under the influence of the extremely low electrostatic pressures which are induced. The diaphragm deflection modulates the reflectance within the optical fiber by varying the gap of the cavity.

Abstract: A method for electro-optic sampling measurement of electrical signals in integrated circuits, capable of improving the reproducibility of the measurements and calibrating the voltage accurately. The changes of beam intensity of a laser beam reflected from an electro-optic probe is measured by using a low frequency signal of a known voltage level to determine a relationship between the changes of beam intensity and gaps between the electro-optic probe and the integrated circuit, then a proportionality of the change of beam intensity and an absolute voltage level for a desired gap is determined according to the determined relationship. Then, the change of beam of intensity at a desired measurement position with a desired gap is measured by using a high frequency signal and the absolute voltage level of the high frequency signal is determined according to the measured change of beam intensity and the determined proportionality.

Abstract: An apparatus and method including a current sensor having a radiation emitter, such as an electrical resistor, and a radiation detector, such as an infrared detector, for sensing current flowing to a plasma generating electrode from a radio frequency (RF) power source. The resistor may include a high emissivity infrared coating to enhance efficiency of the current sensor. The infrared detector provides a highly accurate indication of the average or root-mean-square current delivered to the plasma generating electrode without introducing parasitic capacitance into the measurement, or sensing, circuit. A voltage sensor and a second current sensor, such as a torroidal current sensor, provide the voltage and phase angle of the current delivered to the plasma generating electrode to thereby permit calculation of the power delivered to the plasma generating electrode. A processor controls the RF source responsive to the sensed average current, sensed voltage, and sensed phase angle of the current.

Abstract: A hot line indicator for instantaneously indicating the presence of voltage on an electrical conductor in an AC power distribution system includes a unitary one-piece housing having a projecting metallic probe and a hookeye for engaging a conventional lineman's hot stick. Within the housing, the display electrodes of a high impedance liquid crystal display component are coupled to the monitored conductor through the probe and a capacitive coupling to ground to provide an unambiguous "HL" display indicative of the presence of voltage on the conductor.

Abstract: A polarimetric directional field sensor comprises an emitter and receiver (1) of measurement signals, connected by optical fibers (2, 2a, 2b) to a portable probe (3). The probe (3) comprises an optical element (11, 13) sensitive to the field to be measured and means (9, 20) for polarizing the measurement signal. The optically sensitive element (11, 13) is in the form of a birefringent crystal having a crystalline structure which provides at least one plane in which the induced birefringence is modified by a single component of the field to be measured. The crystal is cut and oriented in the probe so that the direction of propagation of the optical measurement signal inside the crystal is normal to this plane, the polarizing means (9, 20) being oriented at 45.degree. to the orthogonal axes in which the crystal's refractive indices are modified by the desired component of the field.

Abstract: Electro-optical in-circuit testing, especially of large circuits such as those assembled on printed circuit boards, is achieved in an automatic test system by disposing an electro-optical sensor in proximity to the circuit conductors, applying test signals to the circuit under test, and measuring an optical property of the sensor at selected regions thereof corresponding to internal nodes, i.e. test points, of the circuit. The sensor may be an optical probe, having a lens and a layer of electro-optical material which is adapted to be applied to the circuit. The electro-optical material may be either a polymer film or a crystal, the latter requiring a flexible coupling medium on the face applied to the circuit under test. The electro-optical material is provided with a reflective coating on one surface to facilitate a polarimetric measurement made transverse to the plane of the material.

Abstract: An electron-beam test probe system (400) in which a pulsed laser-beam source (404) and a photocathode assembly (430) are used with an electron-beam column (426) to produce a pulsed electron beam at a stabilized repetition frequency. A pulse picker (414) allows the pulse repetition frequency of the pulsed electron beam to be reduced to a submultiple of the pulsed laser repetition frequency. A test pattern generator (416) is programmable to apply a desired pattern of test vector patterns to an electronic circuit to be probed, the test vector patterns being synchronized with the stabilized laser-beam pulse repetition frequency. A timebase circuit (412) allows the test vector patterns to be time-shifted relative to the pulsed electron beam. The electronic circuit under test can thus be probed at any desired point in the applied test vector pattern by control of the pulse picker and by time-shifting the test vector pattern.

Abstract: Visual indication of an operational condition on a printed circuit board by utilizing a pair of LEDs for each operational indication and by utilizing each LED of a pair to verify that the other LED can emit light greater than a predefined level. In addition, if an error condition is determined to exist in a pair of LEDs, a central processor is notified of this fact to allow the error condition to be remedied. Further, if a failure is detected in the pair, both LEDs are utilized to indicate an operational condition on the printed circuit board. This increases the probability that the LED pair will be able to indicate the operational condition.

Abstract: A method and apparatus for testing the proper operation of the optical elements in the optical detection circuit of an electronic register in an energy meter. The light emitter circuit is periodically pulsed adequate to turn the emitters to the on condition, and a comparison circuit is provided in which the voltage across a monitor point in circuit with the light emitters and a switching circuit is monitored both before and after each pulse. The absence of a voltage change upon pulsing the light emitter circuitry is used to generate a first error or failure signal. The light detector is read prior to each pulse to determine if unprogrammed light is being received prior to the pulsing of the light emitter as an indication of tampering with the accurate reading of the energy meter, and a second error signal is generated in response to unprogrammed light.

Abstract: An electro-optical control system having a multi-key keypad, an alpha-numeric display, means for periodically generating a pulsed light beam, means for detecting a portion of the light beam to generate an analog signal, means for converting the analog signal to a digital signal and means for subtracting an ambient light level form the digital data to generate a difference signal. The difference signal is averaged and filtered to generate a digital signal level which is displayed on the alpha-numeric display. The electro-optical control system has two output switches which are activated when digital signal level is between programmed upper and lower limits for each output switch. The values of the upper and lower limits are programmable using the keypad. The upper and lower limits are displayed on the alpha-numeric display as they are generated.

Abstract: Method for particle beam testing of substrates for liquid crystal displays (LCD). This invention is directed to methods wherein, given a substrate (SUB1) for a liquid crystal display, either potentials or, respectively, currents are set in defined fashion with a particle beam (S1, S2 and S4) and/or potentials are measured by detecting secondary electrons (S5) at different switch statuses of the switch elements (T) of the substrate (SUB1). The geometrical integrity and the electrical functionability of the substrate (SUB1) are thereby tested, even though, for example, a supplementary plane electrode is not present for forming a capacitor. An important advantage of the method is that faulty substrates can be repaired or can be segregated even before further-processing and, thus, costs can be reduced.

Abstract: The invention relates to an electric field sensor useful in detecting and measuring wideband transient electrical responses by means of an integrated optical waveguide interferometer. Mach-Zehnder devices are produced wherein one waveguide channel has been reverse poled, or has domain inversion, preferably by means of titanium diffusion into said waveguide channel. Also produced is an electrode-less optical interferometer modulator by which an optical output signal is modulated at the same frequency as an applied electric field.

Abstract: In electron beam measuring, it is often also necessary to measure the frequency range in addition to the measuring time range. In order to do this, according to the invented process, the output signal of the local oscillator of a spectrum analyzer, as is known from conventional high-frequency measuring, undergoes a first frequency conversion and subsequently is utilized for modulating the primary beam. Based on the potential contrast as a multiplicative interaction and the modulated primary beam, the under circumstances very high-frequency signal to be analyzed is transformed to an easily detected low intermediate frequency. Subsequently this intermediate frequency signal is transferred into an input frequency plane of the spectrum analyzer by a second frequency conversion. Both the variable input selection frequency or the fixed intermediate frequency of the spectrum analyzer may be the frequency . The measured result appears in the usual manner on the display of the spectrum analyzer.

Abstract: A system for measuring an electrical signal in a frequency range substantially equal to the bandwidth the signal close to the gigahertz includes two laser sources. A first laser source emits a first light wave which is polarized, then amplitude-modulated by the electrical signal through an electro-optic medium. A second laser source emits a second light wave which is polarized, and then is combined with the amplitude-modulated wave to produce a measurement wave characterizing the phase and frequency of the electrical signal to be measured. The beat between the frequencies of the two polarized waves is checked thereby transposing the measurement wave into the frequency range.

Abstract: The device measures the current intensity in a conductor by FARADAY effect in a monomode optic fiber. It comprises a separator-polarizer formed for example by two coplanar half-disks of polarizing foil, whose polarization directions form a required angle, 90.degree. or 45.degree.. Photodiodes formed by a two-quadrant photodetector in the shape of a disk of the same diameter as that formed by the separator-polarizer, are located behind from the separator-polarizer. The photodiodes are connected to an electronic unit.

Abstract: As the dielectric constant and the halfwave voltage of electro-optic crystals having a fourfold axis of rotary inversion are oppositely dependent on the absolute temperature, but their product is nearly independent of temperature, temperature compensation in an ac voltage measuring system utilizing such an electro-optic crystal is provided by measuring the time averaged current through the crystal. Good electric isolation is achieved by a current sensing circuit which produces a pulsed light signal having a pulse rate proportional to the time averaged current through the crystal. The pulsed light signal is converted to an electrical signal for input to a digital computer which calculates therefrom, and from a reference current and voltage measured at a reference temperature, and a time averaged voltage measurement, a temperature correction factor which is applied to the crystal halfwave voltage used by the computer in calculating the instantaneous value of the voltage to be measured.

Abstract: A system for detecting a fault occurred within a substation and judging a location of the fault including optical current sensors each having a Faraday element arranged on a top of an insulator post of a bus disconnecting switch, a magnetic core arranged to surround a terminal plate of the disconnecting switch to generate a magnetic field corresponding to a current passing through the terminal plate, a laser diode for emitting a laser light beam, an optical fiber for guiding the laser beam to the Faraday element, a photodiode, and an optical fiber for guiding the laser beam transmitted through the Faraday element to the photodiode. The photodiode supplies a signal representing the current passing through the terminal plate to a fault location judging circuit in which the fault location within the substation is judged from the signals from the photodiodes.

Abstract: A method and system for accurate remote reading of an electricity meter including an optical detection arrangement, including a light emitter and sensor, have positioned in the light path therebetween a cutout portion of the meter shaft. Rotation of the shaft affects the amount of light passed to the sensor. Registration errors which may occur in a linear transition operating range are avoided by provision of detector threshold hysteresis. A microprocessor sets timing pulses for emitter energization, establishes a detection period of uniform length of time for each energizing pulse and produces, during each detection period, a digital signal having a logic level indicative of the presence or absence of light transmitted to said sensor, whereby a correlation between light transitions and power usage can be made.

Abstract: In the case of a fiber optics arrangement for measuring the intensity of an electric current while utilizing the Faraday effect in which the magnetic field surrounding the conductor 1 through which the current flows affects the polarization condition of the light, the path of which leads through the core of an optical fiber 2 which surrounds the conductor 1 in the form of a coil, the light coupled out of the optical fiber 2, by means of a beam splitter 9, being divided into two partial light beams, the intensities (I.sub.1, I.sub.2), after passage through one polarizer 12, 11 respectively, being measured by one photodetector 14, 13 respectively, the object of expanding the measuring range of the arrangement is achieved by the fact that the polarizers 12, 11 are rotated symmetrically with respect to one another in comparison to the conventional angle of 45 degrees, the angle (.alpha.

Abstract: A method of measuring C-V characteristics of a semiconductor wafer without forming an electrode on an oxide film thereof. An electrode 201 for C-V measurement is held above a semiconductor wafer 100 across a gap Ge of 1 micrometer or less, and a total capacity including that of the gap Ge is detected. The gap Ge is measured by utilizing the tunneling effect observed in total reflection of light wave. Parallelism of the electrode 201 to the wafer is adjusted by measuring the width of the gap or measuring the capacity of the gap at three different locations on the periphery of the electrode 201.

Abstract: An electromagnetic field intensity measuring apparatus capable of measuring an electromagnetic field intensity accurately and sensitively without affection by any disturbance, including a measuring light generating section for emitting a measuring light containing first and second polarized light components which are orthogonal to each other and slightly different in frequency from each other; an optical input polarization-maintaining fiber for receiving one of the first and second polarized light components in the direction of X-axis polarization and the other polarized light component in the direction of Y-axis polarization, the optical input polarization-maintaining fiber conducting the measuring light to the electromagnetic field measuring place; a sensor section disposed in the electromagnetic field measuring place, the sensor section receiving the measuring light from the optical input polarization-maintaining fiber and modulating the phase of the incident measuring light depending on the electromagneti

Abstract: An apparatus and method for providing a specified amount of heat on a test specimen, a portion of a specimen, or multiple specimens, under space-like conditions. This system includes a vacuum chamber in which one or more test specimens are placed. This chamber is evacuated to the necessary vacuum. One or more external sources of high intensity light is used for providing the necessary temperature. One or more reflectors are used for concentrating the high intensity light. A fiber optic light guide is used for receiving concentrated light from the reflector. A port in the vacuum chamber wall is used so that the second end of the light guide can extend into the chamber so that light exiting the second end impinges on a selected area of the test specimen. A positioning apparatus is used for locating the second end of the light guide within the housing adjacent to vary the test specimen area subjected to the light.

Abstract: Internal test sites on integrated circuit chips may be tested with minimal input/output pad or chip area overhead by providing transient interconnections to the internal test sites using an optically activated photoconductive layer which is formed over the active device layers of the integrated circuit to be tested. The photoconductive layer may be optically activated using an optical mask or hologram, to electrically access the desired internal test sites. Different test sites may be tested using different masks or holograms. The photoconductive layer is preferably hydrogenated amorphous silicon which is highly compatible with standard integrated circuit processing.

Abstract: An apparatus measures the intensity of an electric field with a compact sensor equipped with a light modulater of a Mach-zender interferometer type and a condenser-type antenna. The sensor modulates coherent measuring lights propagated through branched two optical paths according to the voltage induced on the surfaces of plates of a condenser-type antenna of the sensor. The modulated lights are merged and interfered with each other and result in merged light different in intensity from the original measuring light. A waveguide-type optical integrated circuit formed in the sensor calculates the intensity of the merged light having the intensity dependent on the intensity of the magnetic field.

Abstract: A sensor for detecting the firing of a spark plug while maintaining electrical isolation of electronic equipment is disclosed. In the preferred embodiment, a conductive element is attached to one electrical lead of a neon bulb. A wrap secures one end of an optical fiber to the neon bulb for collecting the light from the neon bulb. The optical fiber carries the light from the neon bulb to a data logging device. During use, the conductive element is secured to an insulated spark plug wire and, when the spark plug fires, a voltage between the leads of the neon bulb is induced, causing the neon bulb to produce a pulse of light. The light pulse from the neon bulb is carried by the optical fiber and monitored by the data logging device. By providing an optical fiber to link the data logging device to the neon bulb, electrical isolation is accomplished.

Abstract: An apparatus and method for testing an integrated circuit (12) generally comprises an input pad (14) and output pad (15) having photo-sensitive sensors (20, 46) formed thereon for eliminating the need to come into direct contact with a probe card for testing the integrity of an integrated circuit.

Abstract: An excellent optical magnetic-field sensor having a magnetooptical element, a polarizer, an analyzer and a substrate is provided which can decrease light loss as well as temperature dependency of the modulation rate and prevent displacement and detachment of the magnetooptical element from the polarizer and the analyzer, wherein a synthetic resin adhesive agent is filled in a space between the magnetooptical element and the polarizer and in a space between the magnetooptical element and the analyzer, and the magnetooptical element, the polarizer and the analyzer are respectively adhered or bonded to the substrate.

Abstract: In a fiber-optic sensor for alternating electric fields or voltages, the interference in a bimodal fiber (3) is measured passively. To this end, the mutually phase-shifted near-field and remote-field signals are separated by optical means (15) at the exit end of the bimodal fiber (3), and passed to appropriate detectors (17a, b, c), and the electrical signals created are evaluated by electronic means (18).

Abstract: A system for transducing a signal voltage into an optical signal, transmitting the optical signal via an optical fiber to a remote location in the form of light attenuation frequency and interpreting the light frequency at the remote location to the amplitude and wave form of the signal voltage. The electro optic modulator includes an elongated piezoelectric member which changes length when an electric field is imposed across it. A mirror is attached to a free end of the piezoelectric member and strains or alternately moves toward and away from a partially reflecting surface at the end of an adjacent optical fiber. Light is introduced into the fiber with a portion reflected back by the movable mirror and part by the end of the fiber. A detector at the second end of the optical fiber receives the reflected light.

Abstract: An Electric Power Line Monitoring System in which a single line measuring system station can measure all of the power parameters of both voltage and phase angle plus ambient and line temperatures. The measuring station can be secured to the power line without the need for shutting down the line. The measured data is transmitted from the measuring station on the power line to a ground receiving and data processing station. The system measures true RMS voltage and current values, RMS phase angle along with ambient and line temperatures which are digitized and transmitted through a digital fiber optic data link. The fiber optic data transmission line can be a flexible fiber optic cable assembly or a rigid fiber optic bushing assembly for supporting a long phase conductor that also contains a long resistive link of a voltage sensor voltage divider.

Abstract: Circuit panels, such as LCD panels, are inspected in-process and after final assembly to identify defects. Prior to final assembly, panels identified as having sufficiently few defects are repaired. Similarly after final assembly, panels identified as having sufficiently few defects are repaired. The inspection and repair systems are linked through a repair file. The inspection system identifies each defect by type and location and includes such information in the repair file. The repair system accesses such file and follows a prescribed repair method for a given type of defect at the location of such defect. Simple matrix panel defects include open line defects and line to line shorts. The inspection system includes an automated non-contact capacitance imaging system. The repair system may include a pair of lasers and a film dispenser. A first laser is used to selectively remove material and cut lines. The dispenser is for applying a liquid organic metallic film in the defect area.

Abstract: A lightwave component analyzer including at least an internal optical receiver and preferably also including an internal optical source which are selectively connectable by switches configurable by means of an instrument controller for calibration and performance of electro-optical, opto-electrical, and optical measurements. Transmission measurements of E/O devices are corrected for source match errors, and transmission measurements of O/E devices are corrected for load match errors, in addition to frequency response and cross-talk error correction. Response and match error correction provides for improved measurements of test devices with an electrical port having an impedance different from that of the measurement system impedance.

Abstract: A fiber optic voltage sensor is described which includes a source of light, a reference fiber for receiving a known percentage of the light and an electrostrictive element having terminals across which is applied, a voltage to be measured. The electrostrictive element is responsive to the applied voltage to assume an altered physical state. A measuring fiber also receives a known percentage of light from the light source and is secured about the electrostrictive element. The measuring fiber is provided with a cladding and exhibits an evanescent wave in the cladding. The measuring fiber has a known length which is altered when the electrostrictive element assumes its altered physical state. A differential sensor is provided which senses the intensity of light in both the reference fiber and the measuring fiber and provides an output indicative of the difference between the intensities.

Abstract: An unassembled simple matrix liquid crystal display (LCD) panel, with strips of highly-conductive material, is tested by extracting a two-dimensional image of the capacitance distribution across the surface of the panel under test (PUT) through illumination of a modulator placed adjacent the surface, such as an NCAP modulator or other liquid dispersed polymer-based device. The light modulator is disposed to allow longitudinal probing geometries such that a measurement of capacitance is developed across a gap between the surface of the panel under test and the opposing face of the modulator which causes a power modulation in the optical energy which can be observed through an area optical sensor (such as a camera) for use in directly produce a two-dimensional spatially-dependent power modulation image directly representative of the spatially corresponding capacitance state on the surface of the panel under test.

Abstract: A solid state speed indicator for railroad locomotives is provided with a plurality of indications in addition to speed. These include an acceleration indicator and an overspeed indicator. In addition, the speed indicator is provided with a dual range speed function having at least one particular use in drag operations. A variation of the solid state speed indicator is a retrofit design that replaces the meter movement in existing speed indicator equipment with a solid state display.

Abstract: The optical absorption edge of a semiconductor is shifted toward lower photon energies in an electrical field. The method of the invention utilizes this electro-absorptive effect in order to measure electrical signals of microelectronics in an optical way. A plate-shaped member arranged immediately above the component and scanned by a laser beam serves as a measuring sensor. This plate-shaped member is composed of a carrier crystal which is transparent for the radiation employed, of a conductive layer which is likewise transparent, and of a semiconductor which is dielectrically mirrored at the specimen side, the absorption behavior thereof being influenced by the electrical stray fields emanating from the interconnects. The measured quantity is the intensity of the laser radiation reflected at the dielectric mirror and deflected in the direction of a photodiode.

Abstract: A voltage detecting device using an electro-optical material with a refractive index which is changed by a voltage at a part of an object comprising a light source, comprises an electro-optical material for changing the optical path of the light beam from the light source in accordance with the refraction index of the electro-optical material and a slit or optical fiber extractor at a predetermined position at the output of the electro-optical material for extracting the quantity of light of the light beam at the predetermined position and a detector detecting a voltage at the part of the object from the quantity of light extracted.

Abstract: A method and system for detecting radio frequency emissions in an electrical machine, by: sensing the radio frequency emissions and deriving a light signal modulated by the radio frequency emissions; conducting the light signal via an optical conductor to a location remote from the site of the emissions; and converting the light signal from the optical conductor into an electrical signal representative of the modulation of the light signal by the emissions.

Abstract: A method and apparatus for measuring an electro-optic voltage signal generated in response to an applied voltage signal at a select dot contact of an electro-optic crystal. The applied voltage signal is time averaged along one path to generate an average reference voltage signal, and electro-optically measured along another path to provide a corresponding electro-optic voltage signal. The electro-optic system is fine offset calibrated during a run, with the electro-optic voltage signal measured after the calibration. During the fine offset calibration, the electro-optic voltage signal and the average reference voltage signal are input to an integrator generating a responsive offset signal. The timing correlation between the applied voltage signal the electro-optic voltage signal is randomized during this calibration so that the generated electro-optic voltage signal is an average. The feedback forces the electro-optic signal to the average reference voltage signal level.

Abstract: A Pockels effect electric field sensor includes, as a sensitive element, a crystal with electro-optic properties traversed by a luminous beam with specific polarization and propagation directions. The crystal is cut into the shape of an ellipsoid (14) and has a crystallographic symmetry being either uniaxial 622, 422 or 42m or cubic 43m or 23, the three perpendicular axes of the ellipsoid being orientated along three trirectangular crystallographic axes with the highest symmetry of the crystal.

Abstract: An optical d.c. voltage transformer having an electrooptic medium to which a d.c. electrical field or voltage to be measured is to be applied. The electrooptic medium affects the polarized light from the polarizer by an electrooptical effect to a degree proportional to the strength of the electrical field or voltage. The transformer includes a photodetector for producing an optical signal proportional to the affected light received from the electrooptic medium, a device for converting the optical signal from the photodetector into an electrical signal, a chopper for pulsating the electrical field or voltage to be applied to the electrooptic medium, in terms of time, a detector for demodulating the electrical signal from the converting device in synchronism with the pulsated electrical field or voltage, and an output unit for visually presenting the demodulated electrical signal similar in polarity to the electrical field or voltage to be measured.

Abstract: A proximity detector apparatus that uses the Faraday Effect to detect position changes of a target. The proximity detector includes a permanent magnet having a magnetic field that changes as the target moves to or from a predetermined position. A self-referencing optical sensor is provided that detects the changed magnetic field. The optical sensor includes a magneto-optic material positioned near a node of the magnet. Means are provided to transmit polarized interrogation light along an optical path that includes the magneto-optic material. The optical path is bi-directionally addressed and is non-reciprocal. The optical sensor transduces the changed magnetic field into a modulation of the interrogation light's intensity. Means are provided to detect variations in the interrogation light intensity and to determine a ratio such as the difference over the sum ratio for two interrogation light samples that traveled the optic path in opposite directions.

Abstract: A meter (10) for measuring extremely-low-frequency radiation includes a coil circuit (22) whose output is filtered by a sharp-cut-off high-pass filter (24) to pass standard house-current frequencies but suppress the frequency components that would predominate as a result of movement of the meter with respect to the earth's magnetic field. An integrator (26) compensates for the frequency response of the coil circuit (22), an RMS circuit (35) converts the signal to its root-mean-square value, and a display circuit (28) provides a display determined by the resultant signal.

Abstract: An apparatus and method for non-contact sensing electrical potentials of selected regions on the surface of a sample are provided. A typical sample is an integrated circuit, electronic device, or semiconductor material. The sample is positioned within a vacuum chamber and irradiated with an ultraviolet light beam so that the material emits electrons by the photoelectric effect. The electrons have kinetic energies which are variable according to the electrical potential of the surface of the material. Emitted electrons having kinetic energies within a predetermined range are selected by an electron energy analyzer. An electron detector receives the selected electrons and produces electrical signals corresponding to the energies of said selected electrons. In another embodiment of the invention, a modulated light beam other than the ultraviolet light probe beam irradiates the material in order to produce time varying modulation of the photoelectron energy spectrum.