Abstract: Diamond microtip field emitters are used in triode vacuum microelectronic devices, sensors and displays. Diamond triode devices having integral anode and grid structures can be fabricated. Ultra-sharp tips are formed on the emitters in a fabrication process in which diamond is deposited into mold cavities in a two-step deposition sequence. During deposition of the diamond, the carbon graphite content is carefully controlled to enhance emission performance. The tips or the emitters are treated by post-fabrication processes to further enhance performance.

Abstract: Cathode-ray tube comprising a glass envelope composed of a substantially rectangular faceplate, of a flared rear part and of a substantially cylindrical neck, the flared part including an anode button for receiving the high voltage, the outer surface of the said flared part being partially covered by an electrically conducting layer, adhering to the said outer surface, the electrically conducting layer being a metallic layer composed mainly of aluminium. This layer makes it possible to improve the image distortions due to the drop in the high voltage during current spikes delivered by the high voltage.

Abstract: A luminous display device is disclosed as including a transparent or translucent top body part having a rear surface; a bottom body part having a front side, a rear side, and a trough extending along at least part of the front side of the bottom body part to form a pre-defined pattern; in which the rear surface of the upper body part is in fused sealing relationship with the front side of the bottom body part to form a sealed discharge chamber between the trough and the upper body part; an ionizable gas filling the chamber; and two openings in the bottom body part each having a first end communicating with the chamber and a second end communicating with an electrode, the electrodes being energizable to ionize the gas in the chamber to produce light discharge of the pre-defined pattern.

Abstract: In an AC-driven gas discharge display device and especially a plasma tube array type, a return path is provided for alternate discharge current flowing between X and Y driver circuits. The AC-driven gas discharge display device comprises a front-side, transparent substrate and a rear-side substrate sandwiching therebetween a plurality of thin discharge tubes arranged side by side; a plurality of pairs of display electrodes on an inner surface of the front-side substrate; and a plurality of address electrodes, in a direction transverse to the plurality of display electrodes, the rear-side substrate on an inner surface. Striped light-blocking, electrically conductive films are disposed on an outer surface of the front-side substrate at locations between respective ones of the pairs of display electrodes and coupled at their opposite ends to respective points of a common reference potential in the X- and Y-electrode driver circuits, respectively, to provide a return path for alternate discharge current.

Abstract: An eccentric planar fluorescent tube includes an outer planar fluorescent tubular member that extends substantially but not completely about a center point and which is extended by two inner portions that extend from a first peripheral portion of the outer tubular member and on opposite sides of the center point and terminate at ends proximate to an opposite peripheral portion of the outer tubular member and wherein the ends are connected by a leg member for supplying power to the fluorescent tube. In one embodiment, the leg member includes electrical contacts that extend substantially in a plane of the outer tubular member and, in another embodiment, a central adapter may be provided including electrical contacts that extend transversely with respect to the plane of the outer tubular member.

Abstract: An electron emission device includes a first substrate and a second substrate facing one another and having a predetermined gap therebetween. An electron emission region for emitting electrons is formed on the first substrate, and an illumination portion for displaying images responsive to the electrons emitted from the electron emission region is formed on the second substrate. A grid electrode is mounted between the first and second substrates and configured to focus the electrons emitted from the electron emission assembly. The grid electrode is provided with a plurality of electron passage openings, of which at least one portion of the interior wall of at least one of the electron passage openings is formed with an inclined plane relative to the first substrate.

Abstract: An organic layer (1) is applied to a transparent carrier (2) in such a way that different partial regions with different refractive indices are formed in the layer. Owing to deflection at the phase boundaries within the layer, fewer photons remain trapped in the layer as a result of wave-guiding losses than in the case of homogeneous layers.

Abstract: Methods and devices are disclosed for detecting undesired moisture for a luminescence display device. A moisture detector is encapsulated between two shields with one or more display elements, and has a layer of metal placed in a predetermined location close to the display elements that does not affect an operation thereof, wherein the undesired moisture is detected by monitoring one or more moisture-affected material characteristics thereof.

Abstract: An encapsulation structure of organic electroluminescence device (OELD) is provided. The encapsulation structure comprises a substrate, an OELD, a soft protection layer, a moisture absorption layer and a rigid protective layer. The OELD is disposed over the substrate. The soft protection layer is disposed over the substrate, and encloses the OELD. The moisture absorption layer encloses the soft protection layer. The rigid protective layer encloses the moisture absorption layer.

Abstract: Provided is a plasma flat lamp. The provided lamp includes a discharge gas filled in a discharge area of a discharge container, at least two electrodes generating a gas discharge in the discharge area, a low work function material layer located in a discharge path between the electrodes and collided against gas ions that are generated by the gas discharge, and a fluorescent layer generating visible rays by ultraviolet rays that are generated by the gas discharge in the discharge container. The provided plasma flat lamp reduces a driving voltage due to the low work function material layer against which ions are collided, and increases luminescent efficiency by reducing the absorption of ultraviolet rays of the low work function material layer.

Abstract: A Plasma Display Panel (PDP) includes: a front panel; a rear panel parallel to and separated from a front panel; a plurality of first barrier ribs of a dielectric, arranged between the front panel and the rear panel, and adapted to define discharge cells together with the front panel and the rear panel; front discharge electrodes and rear discharge electrodes disposed apart to surround each discharge cell within the first barrier ribs, each of the front discharge electrodes and rear discharge electrodes including main line parts and corner parts adapted to connect the adjacent main line parts, wherein inner surfaces of the corner parts facing each discharge cell, are rounded; a phosphor layer arranged in each discharge cell defined by the first barrier ribs; and a discharge gas filling each discharge cell.

Abstract: A metal halide fill for a discharge lamp is provided that is comprised of mercury and a mixture of metal halide salts which includes magnesium iodide as a full or partial replacement for calcium iodide. The replacement of at least some of the calcium iodide improves the behavior of the molten salt condensate in the arc tube. In particular, the mixture of metal halide salts contains about 1 to about 50 mole percent sodium iodide, about 15 to about 50 mole percent of a rare earth iodide, about 10 to about 30 mole percent magnesium iodide, about 10 to about 25 mole percent of indium iodide, and about 0 to about 25 mole percent calcium iodide, wherein the sum of the amounts of calcium iodide and magnesium iodide in the mixture is from about 20 to about 45 mole percent.

Abstract: An electrolytic capacitor and a ballast choke of a lighting circuit, are disposed on a first face of a circuit board facing a base, and a one-package switch of the lighting circuit is disposed on a second face, facing a fluorescent lamp. The one-package switch comprises field effect transistors contained in a single package and serve as two inverter switches for driving the fluorescent lamp. The one-package switch is a generally rectangular SMD with dimensions of not more than 6 mm respectively in length and width and mounted on the second face of the circuit board by means of terminals of the one-package switch. The one-package switch enhances heat dissipation properties of the circuit, enables the reduction of its dimensions, and increases the mounting efficiency.

Abstract: An electric circuit for igniting a discharge lamp includes a voltage source, and at least one condenser electrically connected to the voltage source. Further, a series chain is provided, electrically connected in parallel with the condenser, of at least one ignition and at least one inductor. A discharge lamp is electrically connected in parallel with the ignition.

Abstract: A method of operating an arc discharge lamp that has first and second electrodes is described. First, the first electrode is heated with a third electrode with a first arc until the first electrode temperature is sufficiently elevated to allow for thermionic emission. Then, a first voltage is applied between the first and second electrode at a voltage less than 1000 volts to create a second arc.

Abstract: There is explained a plasma display panel that is adaptive for improving brightness uniformity of an entire panel. A plasma display panel according to an embodiment of the present invention has a width, a thickness and a gap of a driving electrode, barrier ribs, a black matrix and a dielectric layer etc in a central area set differently from those in a peripheral area of the plasma display panel.

Abstract: A first electrode layer capable of transmitting visible light, a displaying layer, whose optical characteristics alter in accordance with an electric field, an optical switching layer capable of exhibiting electrical conductivity when being exposed to an electromagnetic wave, and a second electrode layer, which is provided with linear electrodes arrayed in parallel and capable of transmitting the electromagnetic wave, are overlaid in this order. A voltage is applied to each of the linear electrodes and in accordance with image information. Scanning with the electromagnetic wave is performed in two-dimensional directions and from the side of the second electrode layer, the optical characteristics of the displaying layer altering in accordance with an electric field formed between the first electrode layer and the optical switching layer, the image information being thereby displayed.

Abstract: An LED control circuit for controlling a plurality of LEDs with different emission colors comprises a counter which increments or decrements a count value at a predetermined clock in response to a count start signal externally supplied, a signal conversion circuit which converts the count value into an analog signal displaying intensity corresponding to the count value and outputs the analog signal as an output signal, a signal generation circuit which generates, based on the output signal from the signal conversion circuit and brightness data externally specified to its corresponding LED, an analog signal displaying intensity corresponding to a product of the output signal and the brightness data, and a driving circuit which drives its corresponding LED according to the analog signal output from the signal generation circuit, to gradually and simultaneously change the brightness of the LEDs in accordance with the count value.

Abstract: A lamp driving system controlled by electrical isolating is provided. The front-end power stage and the back-end power stage of the lamp driving system are electrically isolated each other by an electrical isolator. The lamp driving system includes a PFC controller for outputting a high voltage into a switching circuit. The switching circuit outputs a lamp driving voltage into the primary side of a boost transformer. A loading resonant network couples to the secondary side of the boost transformer, and generates a feedback signal. There are having the primary side of the electrical isolator, the PFC controller, the switching circuit and boost transformer coupled to a primary ground end. The PFC controller, the loading resonant network and the secondary side of the electrical isolator are coupled to a secondary ground end.

Abstract: Methods and apparatus for providing and controlling power to loads including one or more LEDs. In one example, a controlled predetermined power is provided to a load without requiring any feedback information from the load (i.e., without monitoring a load voltage and/or load current). In another example, a “feed-forward” power driver for an LED-based light source combines the functionality of a DC-DC converter and a light source controller, and is configured to control the intensity of light generated by the light source based on modulating the average power delivered to the light source in a given time period, without monitoring and/or regulating the voltage or current provided to the light source. In various examples, significantly streamlined circuits having fewer components, higher overall power efficiencies, and smaller space requirements are realized.

Abstract: A method of driving a backlight unit is provided. The backlight includes a plurality of lamps sequentially turned on/off. Each of the plurality of lamps is periodically turned on for a predetermined period. The method includes applying a first lamp current to one of the plurality of lamps for a first time period within the predetermined period so that the one of the plurality of lamps emits light with a first brightness, and applying a second lamp current to the one of the plurality of lamps for a second time period within the predetermined period so that the one of the plurality of lamps emits light with a second brightness.

Abstract: The present invention relates to systems, equipment and methods that provide emergency lighting and allow the detection of brownout conditions. One aspect of the present invention is an emergency lighting system with an input voltage interface for receiving an input voltage, a brownout detection component for detecting a brownout condition on the input voltage and generating a brownout signal, a switch mode power converter for altering the input voltage; and an emergency lighting control and battery charging component for controlling the charging of a battery pack and receiving the brownout signal. Another aspect of the invention is a method of providing emergency lighting performed by receiving an input voltage; automatically establishing a brownout threshold relative to the input voltage; and detecting a brownout condition.

Abstract: A system and method for generating white light involves using a combination of phosphor-converted white LEDs and non-phosphor-converted color LEDs to produce white light and adjusting the emitted light in response to feedback signals. Generating white light using a combination of phosphor-converted white LEDs and non-phosphor-converted color LEDs produces white light with an improved CRI and a wide SPD. Adjusting the emitted light in response to feedback allows luminance and chrominance characteristics of the white light to be controlled as the performance of the LEDs changes over time. The emitted light can be adjusted on a per-color basis and/or on a per-group basis, where a group of LEDs includes a combination of at least one phosphor-converted white LED and at least one non-phosphor-converted color LED.

Abstract: A brushless motor according to the present invention provided with a recording disk in a rotational member and serving to rotate the recording disk together with the rotational member comprises a first position detecting means for detecting a rotational position of the rotational member, a second position detecting means for detecting a rotational position of the recording disk, wherein a mode for rotating the rotational member at a high speed by a detection signal of the first position detecting means and a mode for rotating the rotational member at a low speed by a detection signal of the second position detecting means are generated. Thereby, the two rotation states whose rotation speeds are different can be obtained in a simplified constitution.

Abstract: This invention is a “four-direction moving” structure that can move in all four directions without turning first. It contains two groups of wheels that are arranged perpendicular to one another, i.e. four rows of wheels form a quadrate. Within each group, the wheels turn in the same direction. The conventional circular wheels are replaced with circular eccentric or elliptical or noncircular (e.g. polygonal) wheels so that one group of wheels will not impede movement when the other group of wheels is turning by virtue of the longer diameter of the turning wheels.

Abstract: A circuit configuration for supplying the control electronics in an electrical machine is specified, which includes a passive transformer circuit, which is powered by a phase current IP of the electrical machine and which generates an auxiliary voltage VA that is used for supplying the output stage of the electrical machine if no battery is present or if the battery is defective or discharged.

Abstract: A method is specified for operating a rotating electrical machine, in which the rotating electrical machine is connected in terms of phase to a converter circuit, having a DC voltage circuit, for connecting at least two voltage levels, and the phases of the converter circuit are connected to the DC voltage circuit in accordance with a selected switching state combination of switching states for power semiconductor switches in the converter circuit.

Abstract: A control circuit for a cooling fan is provided that adjusts input power and drive a cooling fan. The control circuit comprises a temperature detector for detecting temperature; a power controller for controlling driving power to the cooling fan based on the input power and supplying the driving power; a proportional electric power block supplying control power proportional to temperature variation of the detected; and a fixed electric power block supplying control power at a fixed level when the detected temperature is lower than a predetermined level. The control circuit for a cooling fan is configured to detect temperature variation and to operate with less noise by controlling rotational velocity of the cooling fan in proportion to variation in temperature variation to reduce noise generated when operating the cooling fan.

Abstract: A method and a device for providing field-oriented regulation of a synchronous machine excited by a permanent magnet, in which a direct-axis voltage component and a quadrature-axis voltage component of the control voltage for the synchronous machine are determined from a quadrature-axis current component setpoint value thus determined and from rotational speed information using a stationary machine model in a decoupling network. These voltage components are converted into triggering pulses for the synchronous machine. The regulating system does not require any information regarding the phase currents of the polyphase system.

Abstract: A method for attenuating switching noise from back electromotive force (EMF) observations in a motor is described. The motor is controlled by pulse width modulation (PWM) signals provided at a PWM frequency. The method comprises sampling back EMF observed in the motor at a sampling frequency at least two times greater than the PWM frequency to obtain over-sampled back EMF readings; and filtering the over-sampled back EMF readings to remove switching noise and obtain cleaned back EMF observations. A system implementing the method is also described.

Abstract: A wiper system using two wipers and two wiper motors, which drive the wipers and of which at least one first wiper motor forms a sub-assembly with an electronic control unit. The second wiper motor is a rotary motor having only one sensory system for detecting the absolute and relative rotational position of its driven shaft, which generates corresponding signals for the control unit of the first wiper motor, and the first wiper motor, in the rotational speed and the rotational position of its driven shaft, is regulated by the control unit as a function of the rotational position and the rotational speed of the driven shaft of the second wiper motor.

Abstract: The maximum power point (MPP) of a photovoltaic array that can be coupled to power inverter is determined. A capacitor on a DC-bus side of the inverter is used as a load from which I-V characteristics of the photovoltaic array can be generated. The photovoltaic array is connected to the capacitor, which has been previously discharged by a bleed down resistor. Short circuit current, open circuit voltage, and values of current and voltage as the capacitor charges are determined and used to generate I-V characteristics of the photovoltaic array. From the I-V characteristics, the MPP can be calculated.

Abstract: A high-power permanent-magnet generator in which a stator winding is divided into a first winding part and second winding parts to keep a number of turns less, and capacitors are installed between any different phases to store a current therein to raise a voltage and thereby yielding a high output. The first and second winding parts of independent from one another are both made in a three-phase arrangement of U-phase, V-phase and W-phase. The first and second winding parts are wound in a way staggered one another by one or two slots separating any two adjacent teeth of the successive stator teeth. Further, output lines of three phases are connected across respective capacitors to the remaining other output lines of different phases. The output lines of the first winding part and the second winding part are all installed with respective switches.

Abstract: A single inductor multiple-input multiple-output (SI-MIMO) switching converter time-multiplexes different input power sources through only one inductor to provide multiple regulated output voltages, which can be used to power up different blocks of a portable electronic device (or whatever else it is used for) and at the same time to charge up a rechargeable battery. Power multiplexing is achieved by input switches that are also the switching elements of the switching converter, thus eliminating an additional power multiplexer.

Abstract: The continuous conduction mode (CCM) boost voltage power factor correction apparatus with an average-current control mode of the present invention uses resettable integrators to integrate the difference voltage signal outputted from the voltage error amplifier and the input current signal obtained from detection. The integration results are then compared to control the duty cycle of the switch. Thereby, the input current and the input voltage in the AC/DC electrical power converter have a proportion relation and their phases are the same as each other. The components used in this control method are simpler than the PFC circuit of the prior art. It is easy to integrate in one chip with fewer pins. The apparatus of the present invention has a high power factor and a low total harmonic distortion (THD).

Abstract: A switched regulator circuit provides step-up and step-down operation at high efficiency during light load conditions. Switching loss is reduced in a four switch arrangement by limiting bottom MOSFET switching frequency. The possibility of overcharge in boost mode operation has been avoided by automatically changing to a buck mode operation in response to sensed parameters.

Abstract: A regulator set point circuit. The circuit includes a voltage regulator configured to produce an output voltage. An adjustable voltage source is coupled to the voltage regulator via a feedback circuit, and is configured to generate a voltage adjust signal to control the output voltage.

Abstract: An electric-field meter provided with a housing, an electrode assembly, a shield assembly, a movement assembly, a position detection assembly, a charge measurement circuit, and a leakage current compensation circuit. The electric-field meter can be characterized as a field mill, an induction voltmeter, an electrostatic fluxmeter or an agrimeter. The electrode assembly is selectively exposed to the electric field. The shield assembly alternately covers and exposes the electrode assembly to the electric field. The movement assembly has a source of motive force and a linkage operably connected to one of the shield assembly and the electrode assembly for alternately covering and exposing the electrode assembly to the electric field. The charge measurement circuit receives charge on the electrode assembly. The charge measurement circuit provides a charge detection signal indicative of the charge induced on the electrode assembly as the electrode assembly is selectively exposed to the electric field.

Abstract: A distributed active transformer on a semiconducting substrate is provided. The distributed active transformer includes an outer primary, a secondary disposed adjacent to the outer primary, and an inner primary disposed adjacent to the outer primary and the secondary. A plurality of first three terminal devices is coupled to the outer primary at a plurality of locations. A plurality of second three terminal devices coupled to the inner primary at a plurality of locations, and each second three terminal device is disposed opposite from and coupled to one of the plurality of first three terminal devices. A plurality of power control actuation circuits is also provided, where each power control actuation circuit is coupled to one of the first three terminal devices and the second three terminal devices.

Abstract: A magnetic field generated by a primary winding (1) in which the current (i1) to be measured flows is balanced by a magnetic field of opposing direction generated by a secondary winding (2) in which a compensating current (i2) flows. The device includes a member (3) sensitive to the field resulting from the addition of the magnetic fields of opposing directions to regulate the compensating current (i2) in closed loop mode. According to the invention, the, sensitive member (3) is sensitive only to the direction of the resultant field and, in return, controls the reversal of the direction of circulation of the compensating current (i2) in the secondary winding (2). This sensitive member (3) can be formed by a Hall effect probe with bipolar output signal. The device is suitable for the measurement of a current inautomotive electronics.

Abstract: A wide bandwidth attenuator input circuit for a measurement probe has a Z0 attenuator circuit coupled in series with a compensated RC attenuator circuit. The series attenuator elements of the Z0 and the compensated RC attenuator circuits are coupled via a controlled impedance transmission line to the shunt attenuator elements of the Z0 and the compensated RC attenuator circuits. The shunt element of the Z0 attenuator element terminates the transmission line in its characteristic impedance. The junction of the series and shunt attenuator elements are coupled to the input of a buffer amplifier. At low and intermediate frequencies, the compensated RC attenuator circuit attenuates an input signal while at high frequencies, the compensated RC attenuator circuit acts as a short and the Z0 attenuator circuits attenuates the input signal.

Abstract: A sensor body for use in a pig for determining characteristics of a pipeline wall though which the pig passes includes a circuit board and a single coil wrapped around the circuit board. A microcontroller is mounted to the circuit board and connected to the single coil and configured to induce a waveform on the coil to thereby create an eddy current in the pipeline wall adjacent the sensor body. The microcontroller is also configured to measure changes in a characteristic of the induced waveform on the single coil that correspond to the presence of anomalies on an inside diameter of the pipeline wall. The sensor body also includes a sensor body cover molded about the circuit board, the microcontroller and the single coil. The sensor body cover consists essentially of a wear resistant, non-conductive material that includes a polymer material.

Abstract: An eddy current detection system configured in accordance with an example embodiment of the invention employs a high frequency rotary eddy current probe that is capable of detecting very shallow surface imperfections, including imperfections originating at scribe lines located near lap joints on an aircraft fuselage. The rotary eddy current probe includes a differential sensing coil arrangement surrounded by a reflection coil, both of which are located within the probe tip housing of the rotary eddy current probe. The differential sensing coil arrangement and the reflection coil are positioned off-axis within the rotary eddy current probe. In addition, the rotary eddy current probe employs a partial electromagnetic shield that does not completely surround the differential sensing coil arrangement.

Abstract: A magnetic resonance imaging system includes a high-frequency magnetic field generating unit for generating and applying a high-frequency magnetic field to a subject placed in a static magnetic field, a gradient magnetic field generating unit for generating a gradient magnetic field to be superimposed on the static magnetic field, and a sequencer for controlling the high-frequency magnetic field generating unit and the gradient magnetic field generating unit to acquire, within a specified part of the heartbeat of the subject, MR data that pertains to a plane through which an axis substantially identical to the body axis of the subject in a k-space extends, and to cause the plane to rotate, at every heartbeat, about the axis substantially identical to the body axis.

Abstract: The present invention includes a method for MR imaging of a biological matter having H2O17 content by performing T1?off imaging of said H2O17 content in said biological matter. The T1?off imaging is performed by applying an RF pulse with a resonance frequency offset to said biological matter to create off resonance spin locking conditions in said biological matter. Thus, parts of the biological matter having different H2O17 concentrations are differentiated because of their different T2/T1 ratios.

Abstract: A magnetic resonance imaging apparatus comprising an imaging condition setting unit, a gradient coil, a radio frequency coil, a data acquisition unit, an image reconstructing unit and an image data generating unit. The imaging condition setting unit sets a first imaging condition and a second imaging condition at least. The data acquisition unit acquires first magnetic resonance signal data corresponding to the first imaging condition and second magnetic resonance signal data corresponding to the second imaging condition. The image reconstructing unit reconstructs first three dimensional image data in accordance with the first magnetic resonance signal data and second three dimensional image data in accordance with the second magnetic resonance signal data. The image data generating unit combines the first three dimensional image data and the second three dimensional image data to generate third three dimensional image data.

Abstract: A magnetic resonance apparatus has a scanner having a basic field magnet, a stationary gradient coil unit, an antenna system for acquisition of magnetic resonance signals, and a second gradient coil unit that can be introduced into an examination chamber of the scanner. The second gradient coil unit is arranged on a displaceable mounting attached outside of the examination chamber. The mounting is fashioned as a C-arm that can be moved along one axis.

Abstract: A galvanic resistivity tool with one or more measurement electrodes and guard electrodes, and one or more shielding electrodes. The potential difference between the measurement electrodes and the guard electrodes is controlled to minimize current flow between the measurement electrodes and the shielding electrodes. This provides improved focusing and avoids effects of contact impedance.

Abstract: A device and method for testing seal tightness of a fuel tank system of a motor vehicle, wherein excess pressure is built up in the fuel tank system by an electrically operated pump and electric current consumption of the pump is compared to reference values in order to determine whether the seal tightness of the fuel tank system is sufficient, and wherein the fuel tank system includes a filler neck with a locking fuel tank cap. A control line is connected in parallel to the power supply line of the pump, the control line being guided across an electric tank cap switch, which assumes a different switch state when the filler neck is closed properly than when it is not closed properly. In at least one of these lines, an electric resistor is installed, which allows a determination of the switch state of the tank cap switch.

Abstract: In the measurement of partial discharge, a voltage detected by an antenna is input to a spectrum analyzer and a phase difference between an operating voltage and a power supply of the spectrum analyzer is obtained by phase domain analysis using the spectrum analyzer. Based on the phase difference and the voltage phase shift associated with the input impedance of a signal converter circuit, the time axis displayed on the screen of the spectrum analyzer is compensated. After the compensation has been carried out, the voltage detected by the antenna is input into the spectrum analyzer and the partial discharge pattern which synchronizes with the operating voltage is measured by phase domain analysis using the spectrum analyzer.