Asea Brown Boveri Inc.

Bbc Brown, Boveri & Company, Limited

Bbc Brown Boveri Ag

Euro Emc Service Dr. Hansen Gmbh

Diethard Hansen

Dietrich Konigstein

Niyazi Ari

Hans Schar

Heyno Garbe

Hendrik Hoitink

Dieter Koster

Eva Roth

Thomas Schreiber

Detlef Ristau

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.

Method and apparatus for generating and receiving electromagnetic waves

A reflection-free termination of a TEM waveguide, in which a TEM wave is conducted through an inner conductor (4) and an outer conductor (1) and is absorbed at one end of the TEM waveguide by an RF absorber (5) for absorbing a field energy and by an ohmic line termination (7) for absorbing a conductor-guided energy of the TEM wave, is constructed in such a manner that the line termination (7) is located in a plane determined by the inner conductor (4) and located in the wave direction. The line termination (7) is constructed as an ohmic resistance which produces a gradual, serial damping on the inner conductor (4) and locally compensates for a capacitance loading additionally produced at the line termination (7) by the RF absorbers.

Reflection-free termination of a TEM waveguide

A device for calibrating and testing ring-shaped current clamps comprises a calibration housing with an outer conductor enclosing the current clamp, and an inner conductor passing through the current clamp. The outer conductor encloses the current clamp on all sides and is adapted to the shape of the current clamp. The calibration housing also exhibits, with the current clamp accommodated therein, an impedance Z.sub.L which is predetermined by a measuring system. These measurement make it possible to measure the frequency response of the current clamp precisely, up into the GHz range. The calibration housing exhibits transitions which are conically tapered towards the connections (6, 7).

Device for calibrating and testing ring-shaped current clamps

A method for comparing the quality of RF absorbers uses a TEM cell which is provided with a low-reflection termination, in which cell the absorber wall (5) is equipped with reference absorbers (13). A steep-edged pulse wave is radiated in by means of a pulse generator (9) and a scattered wave reflected by the test absorber (14) is detected by means of a sensor (10). A reflection of the absorber wall is then determined by means of a first calibration measurement. The reference absorber is removed in a test area and a reflection of a metal wall (8) lying behind it is then determined by means of a second calibration measurement. Finally, a reflection of the test absorber (14) arranged in the test area is determined in a comparison measurement.

Method for comparing the quality of RF absorbers

In an arrangement for measuring transfer impedances of coaxial systems (3), a generator (1) is connected via a coaxial, supplying system (2) to a conductor shield (6) of the coaxial system (3) at a first end of the coaxial system (3). A voltage measuring instrument is connected to the first end between the conductor shield (6) and the inner conductor (5) of the coaxial system (3). The electrical contact between the supplying system (2) and the conductor shield (6) is created by a gripping collet (12). The conductor shield (6) and the inner conductor (5) are short-circuited at a second end of the coaxial system (3).

Arrangement for measuring transfer impedances of coaxial cables

In a method for measuring a characteristic impedance and a propagation constant of a two-port network (2), an output port (5) of the two-port network (2) is successively terminated with at least two different finite known impedances (3a, 3b) which are independent of the two-port network (2). An input impedance (ZE1, ZE2) is measured for each residual impedance. From the termination impedances (ZA1, ZA2) of the impedances (3a, 3b) and the corresponding input impedances (ZE1, ZE2), the propagation constant and the characteristic impedance are determined.

Method for measuring a characteristic impedance and a propagation

The present invention relates to a generator concept by means of which, in particular, the effects of so-called nuclear electromagnetic pulses on electrical or electronic devices can be simulated by applying the so-called current injection technique. In the context of the generator concept according to the invention, in particular, a pneumatically controllable very fast spark gap is disclosed. Furthermore, a generator circuit having two spark gaps (40, 41) is disclosed which is capable of generating a voltage pulse having an amplitude which is four times as large as the voltage of its voltage supply. With the exception of the spark gaps, the components 42-49) of the generator circuit only need to be designed for the above voltage of the voltage supply with respect to their continuous loading. The generator circuit according to the invention, in particular in conjunction with the spark gap according to the invention, allows a very fast efficient pulse generator to be constructed.

Emp generator

The device according to the invention exhibits a TEM waveguide (1), which opens out in a pyramid shape and which is closed by a wall (7) of high-frequency peak absorbers (7.1) and which exhibits an asymmetrically disposed, plate-shaped inner line (6), which is connected to a plurality of terminal resistors (8.1, 8.2, 8.3) through the absorber wall (7). The TEM waveguide (1) further exhibits a closed outer line (5). The absorber wall (7) is curved in the manner of a spherical segment, the center of curvature being situated in the region of the tip (2) of the pyramid-shaped TEM waveguide (1).

Device for the EMI testing of electronic systems

Zinc oxide surge arresters are used to replace capacitive elements for voltages below the pick-up voltage of the surge arrester. Advantageously, the surge arresters may be provided in an alternating current network to provide a high degree of protection against transient disturbances without increasing cost.

Zine oxide surge arresters

A gas-filled test cell is used which accommodates the object under test and to which a pulse generator is connected. The test cell is constructed over its entire length as a coaxial line having a ribbon-shaped inner conductor and a round outer conductor. A ribbon-shaped potential plate connected to the outer conductor is arranged plane-parallel to the inner conductor inside the outer conductor at a distance corresponding to at least twice the height of the object under test. The distance is also longer than the shortest distance between the inner conductor and the outer conductor. The ratio between the sum of the width of the inner conductor and its thickness and the diameter of the outer conductor has been selected in such a manner that is between 0.4 and 0.9.

Device for testing electrical or electronic systems with electromagnetic

The present invention relates to a protective device for a load connected to a power supply line of an electric power system, comprising an LC network having low-pass characteristics, connected into the power supply line on the system side preceding the load. So that disturbances with frequencies below the cut-off frequency of the LC network can also be kept away from the load, a switching element controlled by a monitoring device is arranged according to the invention in series with the LC network in the power supply line. The monitoring device is connected to the power supply line on the system side at a junction preceding the switching element and keeps the switching element closed only for as long as the instantaneous value of the time derivation of the voltage on the power supply line deviates from the instantaneous value of a nominal value which is predeterminable in its variation with time, by no more than an equally predeterminable amount.

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Berikon, Switzerland

Diethard Hansen