Abstract: The invention relates to a method of detecting a shielding defect of a shielded cable mounted in a building which defines between an instrument and the shielding of the cable, a first stray capacitance; the method steps are:placing measurement apparatus in such a manner as to define a second stray capacitance between itself and the building;injecting a high frequency signal into the shielding of the cable, by means of the measurement apparatus, the signal circulating back to the apparatus via the first and second stray capacitances; andmeasuring on the core of the cable, a signal that appears by radiation due to the injection of the high frequency signal, and representative of a defect in the shielding of the cable.

Abstract: A charged voltage between the ground and a positive pole of backup capacitor 5 and a ground-casing voltage developed between the ground and a casing of capacitor 5 are determined. When the ground-casing voltage is smaller than a first value, it is judged that capacitor 5 has an opened circuit on its positive pole side; when the ground-casing voltage is larger than a second value, it is judged that capacitor 5 has an opened circuit on its negative pole side. A difference between the ground-casing voltage and the charged voltage is divided by the ground casing voltage so that a coefficient is obtained. When the coefficient is outside a predetermined range of values, it is judged that capacitor 5 is poor in capacitance, which makes it possible to determine, even in operation, whether capacitor 5 functions properly.

Abstract: A temperature compensation module for use with battery charger/rectifier units. The compensation module is used to vary the battery charger output voltage as a function of temperature. This is done by controlling the series impedance of the charger's voltage sense leads. The impedance is controlled to produce a voltage offset in series with the sense leads. Thus, the charger's output voltage is equal to its adjusted output voltage plus the offset voltage.

Abstract: A method of determining a response characteristic of a microwave device includes coupling a microwave resonator to the device, loading the resonator with microwave radiation, monitoring the time decay of power from the resonator, and comparing the monitored time decay with a known characteristic of the time decay of radiation in the microwave resonator when loaded with radiation.

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: The invention includes a method and device for determining the in-situ density of a porous material. A resistivity measuring device applies an electrical current through an electrode array to measure the resistivity of the porous material. The resistivity measuring device may also be used to measure the resistivity of a pore filling fluid. A formation factor and in-situ density constants of the porous material are determined using empirical methods. In-situ moisture content of the porous material is determined. The above data is applied to a general geophysical in-situ density equation to calculate the in-situ density of the porous material.

Abstract: A process and a system for the operation of a resistive moisture sensor, in particular on the windshield of a motor vehicle, wherein the conductivity of the moisture sensor is measured shortly after a sudden change in a signal fed to the moisture sensor and measured at at least one later time. Information as to the nature and degree of the dirtying of the windshield is obtained by the measured values.

Abstract: A method and device for determining the hydraulic conductivity of porous materials is disclosed. The method uses a general permeability equation for calculating the hydraulic conductivity. The resistivity of the porous material is measured when the porous material is at least partially saturated with a pore filling fluid. Other data, such as a formation factor, permeability constants of the porous material, and in situ moisture content of the porous material may also be derived or measured. The geophysical permeability equation is then used to calculate the hydraulic conductivity of the porous material from the measurements and data. Methods are also disclosed which provide an average hydraulic conductivity over a given area. A device for determining hydraulic conductivity of a porous material is disclosed which utilizes a plurality of electrodes for conducting electricity to the porous material. A resistivity meter may be attached between the electrodes for measuring the resistivity.

Abstract: In a first measurement step, the two test probes of a measurement apparatus are contacted with two of the three phase lines. The measurement apparatus determines the frequency of the three-phase voltage. In a subsequent second measurement step, one of the two test probes is brought into connection with the remaining third phase line. The other test probe is held in contact with the other line. In the second measurement step the voltage level or voltage profile on the third phase line is evaluated inside the measurement apparatus in comparison to the first phase line during one or more time windows of length .pi..

Abstract: Microwave radiation emitted from a single antenna is focused on a targeted material from which reflected radiation is received by the same antenna to provide signal measurement data from which detected material defects are evaluated by determination of void location and size. Antenna position and orientation is adjusted to obtain the signal measurement data from of the microwave radiation reflection along at least two target incidence paths from the same target location, one of which is normal to said targeted surface of the material and the other oblique thereto at a scattering angle at which the signal radiation intensity is minimized.

Abstract: A sensor for the measurement of moisture in a flow of material, especially loose material such as meal material, grains, granulates and similar materials which are to be pressed to form feed pills in presses. The sensor comprises a tube piece of an electrically conductive material with circular cross-section, and an elongated pole which is of circular cross-section and is disposed with its longitudinal axis concentrically and electrically insulated in the tube piece, and which consists of an electrically conductive material. When the moist material flows between the inside surface of the tube piece and the outer side of the pole, the sensor works with the moist material's conductivity as a condenser for the capacitive detection of the moistness, which can be determined on the basis of the detection.

Abstract: A system and a method for moving a measuring device (4, 30) to a plurality of positions above a test object (12), e.g. an electrically or electronically equipped printed board, at which the EMC, of the test object (12) is measured and later stored in a memory together with the position of the measuring device. The system includes a computer (18) and a measuring device (4, 30). The positioning device (8) moves the measuring device (3, 30) across the test object (12) from one position to another, wherein the number of positions and their coordinates are preselected and stored in a computer (18) for a later repetition of the measurement. Each position is assigned with a measurement value which is stored in the memory of the computer (18) together with the coordinates of the measuring device (4, 30). At each position, the power to the control devices is shut-off, in order to minimize interference with the measurements.

Abstract: The invention describes a method and an apparatus for generating and receiving electromagnetic waves for test purposes and is applicable particularly for measurements, investigations and tests of electromagnetic compatibility. For testing the immunity, the test piece is acted upon with defined field parameters and, during the emission measurement, the electromagnetic radiation emitted by the test piece is measured. It is an important distinguishing feature of the invention that a cell, constructed as a TEM waveguide, is rotated about the test piece. The apparatus is characterized in that the lid and bottom of the pyramidal cell are constructed so as to be electrically conducting and in that two-dimensional septa, which consist of individual wires of equal length, are disposed in each case symmetrically at a small distance from the lid and the bottom.

Abstract: A microprocessor control (10, 24) has one or more temperature responsive thermistor sensors (20, 26, 28) used to provide temperature inputs to control operation of a temperature control system. The microprocessor control subjects the thermistor sensors to a series of diagnostic tests prior to reading the thermistor sensors, the tests including short and open circuits, shorts to ground or power and leakage paths to ground. The thermistors, along with a reference resistor (R11, R26) form an RC charge circuit with a capacitor (C6, C6'). The capacitor is charged through each thermistor and reference resistor for selected open and short tests while a watch dog timer is used to determine the time taken to charge the capacitor via a timer capture port coupled to the capacitor.

Abstract: An apparatus for demonstrating and testing the operation of an arcing fault detector. The apparatus comprises an electrical circuit including line and neutral conductors connected between a power source and a load. A selector switch is movable between a first position and a second position in order to selectively route load current across either an arcing fault detector or standard circuit breaker. A pair of electrodes is positioned between said selector switch and the load for producing an arcing condition on the line conductor.

Abstract: A hand-held ignition voltage tester for detecting voltage on a spark plug wire in an ignition system, such as a distributorless ignition system. The tester includes a housing, positive and negative power cables and a capacitive probe for capacitively coupling to the spark plug wire. The capacitive probe generates a voltage signal which is representative of the voltage on the spark plug wire. A plurality of voltage level indicators are mounted to the housing to form a bar graph, with each indicator corresponding to a selected voltage level. A measurement circuit is coupled to the power cables and the capacitive probe for activating the voltage level indicators in response to the voltage signal.

Abstract: An apparatus for medical diagnosis and/or therapy, includes an electromagnetic obstacle sensor. Due to variations of the ambient temperature and humidity and/or due to the hanging of, for example a cloth around the sensors (16,18), drift of the zero point of the control may occur, so that the approaching of an obstacle by a movable part (6) of the apparatus could be incorrectly interpreted by the apparatus. In order to compensate for such drift there is provided a control unit (25) for automatically controlling the output signal V.sub.o of the receiver (27) back to the zero value in the absence of an object in the vicinity of the movable part (6). This control preferably takes place at a comparatively high speed when a cloth or moisture is moved into the vicinity of the sensors, and at a comparatively low speed upon removal of the cloth or the moisture.

Abstract: In estimating the residual capacity of a battery according to the maximum output estimating process, a reference point is established in advance at the intersection of a plurality of current/voltage characteristic linear curves corresponding to various residual capacities of the battery or in an area in the vicinity of the intersections of the curves. A current/voltage characteristic linear curve is determined so as to pass through the reference point and a measured operating point of the battery which corresponds to the present discharging current and output voltage values measured when the battery is discharged. Then, a maximum transfer power value of the battery is determined from the current/voltage characteristic linear curve thus determined, and the present residual capacity of the battery is estimated from the maximum transfer power value.

Abstract: A method and apparatus for fast response and distortion measurement of a signal transfer device. A computer processor generates a multitone test signal of predetermined duration and stores it in a memory. The test signal is read out, converted to analog form, if necessary, and applied to the input of a device under test. The output produced by the device under test in response to the test signal is acquired and digitized, if necessary, and a Fast Fourier Transform is performed on the acquired data to determine its spectral characteristics. Frequency response, harmonic distortion, intermodulation distortion, phase distortion, wow and flutter and other signal transfer characteristics are measured by the CPU by analysis of the output signal.

Abstract: A particle detector is designed to detect particles such as cells and blood corpuscles, and this particle detector includes means for passing and recovering a multilayer flow consisting of an inner layer A of conductive liquid specimen, a middle layer B of conductive first sheath liquid, and an outer layer C of nonconductive second sheath liquid surrounding them, in an orifice 12, and a pair of electrodes disposed on both sides of the orifice so as to contact the conductive liquid respectively. A detector circuit 44 is connected to the pair of electrodes so as to detect a particle signal on the basis of difference of electric impedance between the electrodes. The diameter of the orifice 12 is substantially the diameter of the middle layer. By varying the flow rate balance of the conductive liquids and nonconductive liquid, the diameter of the middle layer may be freely changed. Accordingly, the diameter of the orifice may be apparently changed as desired.