Abstract: A security element for authenticating bank notes, credit cards, security passes and the like is disclosed. The security element incorporates a reflective-type diffraction grating, which grating comprises a continuous layer of reflecting material on which is deposited a layer of dielectric material. Non-continuous reflecting layer portions are embedded in the dielectric material. It is practically impossible to lay bare the diffraction grating without destroying it.

Abstract: A method for forming and transmitting information carrying signals in an electrical power distribution network is disclosed. A step-shaped current signal is produced by switching at least two purely ohmic loads between a pair of power lines. The ohmic loads are switched between the power lines in accordance with a predetermined sequence so that a current signal having the desired waveform results. The step-shaped information carrying signal usually has a frequency which is higher than the power transmission frequency of the supply network.

Abstract: A circuit for providing temperature compensation to a Hall element is disclosed. The temperature compensation circuit is used to generate control signals which act on the effective thickness of the current channel of the Hall element in a manner so as to oppose changes in the effective thickness of the current channel produced by temperature variations.

Abstract: A stepping motor is disclosed, which includes an inventive arrangement of stator pole arms. The arrangement of stator pole arms has the effect of smoothing out the drive torque characteristic of the stepping motor.

Abstract: A current transformer equipped with a primary winding (1), a secondary winding (2), as well as a detector winding (3), has a rigid coupling between the secondary winding (2) and the detector winding (3). The coupling factor between these windings (2, 3) and the primary winding (1) is considerably smaller than one, since only one portion of the magnetic flux .phi..sub.1 created in the primary winding (1) by the current I.sub.1 to be measured is detected by the detector winding (3). This partial flux .phi..sub.13 is compensated by the flux which is created in the secondary winding (2) by means of a variable-gain amplifier.

Abstract: A precision measurement voltage transducer is fed from a reference alternating current source and comprises a transformer and a servo amplifier. The transformer comprises a feedback winding, a magnetizing winding and an output winding. The feedback winding and the magnetizing winding together with the servo amplifier form a feedback control regulating system, which adjusts the input voltage of the servo amplifier to zero. The latter comprises two amplifiers, which according to a first embodiment are connected in series and which according to a second embodiment feed the two poles of the primary winding of a second transformer, the secondary winding of which forms the output of the servo amplifier. According to the first embodiment the second amplifier is provided with a positive and an equally strong negative feedback and according to the second embodiment the transfer ratio of the second transformer equals the amplification factor of the second amplifier.

Abstract: The current to be measured (I) within a conductor (1), is branched into two conductors (3, 4) of the same conductor material, which have a resistance differing relatively little from one another and at opposite winding direction form the primary winding of an active current transducer. The secondary current (i) is determined by the resistance ratio of the two individual conductors (3, 4). Through mechanical, and therewith thermal contact between the two individual conductors (3, 4), their resistance-ratio is also maintained at high temperature coefficients and at higher conductor temperatures.

Abstract: A method for the mechanical soft-soldering of heavy metals using a novel fluxing composition is described. The fluxing composition comprises up to 3% by weight of an organic acid based fluxing agent, with the fluxing agent being dissolved in an organic solvent. Succinic acid may be used as the fluxing agent and isopropanol as the solvent. The solution can contain non-ionogenic wetting agents. The solution also contains a carrier component which can be removed by the liquid solder during the soldering process and which effects a removal of the residues of the fluxing agent at the end of the soldering process. The fluxing solution is cleaned through fine-filtration prior to use. The carrier component comprises an ester or an organic acid, said carrier component being liquid at the soldering temperature. Through the use of the carrier component, the formation of bridges and lugs is eliminated.

Abstract: For protecting the surface of a soldering bath a covering means is used which comprises two phases (3,4), which are placed one on top of the other, are not soluble in each other and are liquid at the soldering temperature. The bottom phase (3) is produced by spreading over the top phase (4), which consists of a liquid synthetic polyalphaolefin, a powder of a chemically active component of sebacic acid and/or suberic acid which is solid at room temperature and liquid at the soldering temperature.

Abstract: A compensated measurement transducer for measuring a first current generates a first magnetic field of a predetermined direction which flows in a first circuit including a first conductor; a second current substantially similar to the first current is generated in a second circuit and the first current is measured by obtaining the value of the second current. The second circuit includes a compensating current conductor, which generates a second magnetic field, compensating the first magnetic field, a Wheatstone bridge to which both magnetic fields are applied, and an amplifier connected to the output of the Wheatstone bridge, and coupled to the compensating current conductor. An auxiliary magnetic field is applied to the Wheatstone bridge, which is connected to a current- or voltage-source, and includes four ferromagnetic and magnetoresistive thin film.

Abstract: An apparatus for determining the reactive energy of a circuit includes a mark-space modulator, which has an input terminal normally accepting a first signal input, and an output terminal, a pulse amplitude modulator which has a bipolar modulating terminal normally accepting a second and bipolar signal input, a signal output terminal, and a pulse input terminal, and a delay circuit which has a data input terminal connected to the output terminal of the mark space modulator, and which has an output terminal connected to the pulse input terminal of the pulse amplitude modulator. A predetermined phase angle at an operating frequency of the delay circuit normally occurs between the input terminal and the output terminal of the delay circuit. A regulator is interconnected between the mark-space modulator and the delay circuit so as to maintain the phase angle at the operative frequency as close as possible to 90 degrees, even when the signal input is subject to any level variations or to any interference.

Abstract: The present invention relates to a current divider for a measuring transducer. The current divider includes two conductors. The first conductor, which is operable as a shunt, comprises two generally flat legs which extend parallel to one another. Each leg defines one aperture into which the core of the measuring transducer extends. The second conductor is z-shaped having two arms and a bridge extending between the two arms. The arms are electrically connected to one of the legs and the bridge crosses the aperture therein, so that the bridge is surrounded by the core.

Abstract: A document includes a substrate which has an outer surface and defines a plane, and a coordinate system which is defined with respect to the plane. A diffraction-optical authenticating element covers at least part of the outer surface, and generates at least one color pattern constituting a visually testable feature which verifies the authenticity of the document. The diffraction-optical authenticating element provides a color pattern moving at a predetermined velocity along a predetermined track when the document is illuminated from a first direction and viewed from a second direction, as defined with respect to the coordinate system, upon the document being rotated within the plane along a prearranged sense of rotation, and at a prearranged velocity.

Abstract: A transducer free of any magnetic core for contactless measurement of a current includes an electrically conducting strip adapted to carry the current in a predetermined direction. The current thus generates a first primary magnetic field which has a direction at right angles to the predetermined direction near one side of the strip, and a second primary magnetic field near the other side of the strip, which has a direction opposite to the predetermined direction. A first magnetic field sensor near one side measures the first primary magnetic field and provides a first output signal, and a second magnetic field sensor near the other side of the strip measures the second primary magnetic field, and provides a second output signal. A circuit connected to the first and second magnetic field sensor processes the first and second output signals, and generates an output signal proportional to the measured current.

Abstract: An apparatus for embossing a high resolution relief pattern such as a phase hologram or diffraction grating from a mold onto a thermoplastic material is disclosed.The apparatus comprises first and second adjacent disks adapted to rotate in opposite senses, the disks serving to define an embossing zone therebetween in which the circumferences of the disks exert pressure on one another. The first disk serves to transport the thermoplastic material to the embossing zone. To preheat the thermoplastic material, a preheating band of limited length is mounted under tension on the circumference of the first disk, the preheating band being resistively heated by a longitudinally flowing electric current. A resistively heated band-shaped embossing mold is mounted on the circumference of the second disk. The embossing mold and the thermoplastic carrier come into contact with one another in the embossing zone.

Abstract: In an apparatus and a method for examining the authenticity of a document, which includes at least a machine-readable authenticity feature in the form of an optical microstructure for diffracting at least one component of a beam of light rays which has a wavelength of a first predetermined value and impinges on the microstructures along a predetermined direction, a light source for emitting the beam of light rays, and wherein the components of the light rays diffracted from the microstructure have an intensity distribution defining an effective center line of "gravity" along one direction of diffraction, a light-sensing device for sensing the light rays diffracted from the microstructure and for generating electrical signals from the sensed light rays, and an evaluator for processing the electrical signals generated by the light sensor, and for deriving from information contained in the processed electrical signals a YES/NO decision whether the document is authentic or not, there is provided a control connect

Abstract: A security blank is formed with a light-redirecting spatial structure including a deterministic component establishing at least one authenticating feature, and a stochastic component superimposed on the deterministic component, and sufficiently obscuring the deterministic component so as largely to frustrate recognition of the function of the authenticating feature by intensity measurement of light reflected therefrom. Recognition of the function of the authenticating feature is made possible by a method and an apparatus measuring the degree of coherence of two narrow bundles of light rays obtained from light reflected from the spatial structure upon its illumination by light of a selected wavelength.

Abstract: In an apparatus for the measurement of electrical power, including a multiplier which receives on an input thereof an electrical signal proportional to the voltage component of the electrical power, and which is subjected to an external magnetic field proportional to the current component of the electrical power, an auxiliary magnetic field is applied to the multiplier. The multiplier is a Wheatstone bridge including four ferromagnetic and magnetoresistive thin films, and the magnetic fields have a direction along the direction of the hard magnetic axes of each of the thin films. The thin films are so positioned that the magnetization of two electrically oppositely disposed thin films resulting from the application of the external magnetic field thereto is rotated in a direction opposite to that of the correspondingly resulting magnetization of the remaining thin films, following application of the auxiliary magnetic field to the films.

Abstract: A current to pulse-sequence transducer for transforming a current to be measured into a sequence of pulses which has a certain mark-to-space ratio, includes a first transforming device for transforming the current to be measured into a measurement magnetic field, a second transforming device for generating a reference magnetic field, and magnetic field comparison device including a magnetoresistive thin film comparator normally providing a zero output when the fields are equal, but generating an impulse when the strength of one magnetic field exceeds that of the other, and an impulse processing device. The impulse processing device includes a differentiator amplifier connected to the output of the magnetoresistive thin film comparator and a Schmitt trigger circuit postcoupled to the differentiator amplifier.

Abstract: In an apparatus for synchronizing received binary signals, the duration of each bit of the received signals to be synchronized is an integral multiple n of the duration of an original bit, and each original bit has a reception quality factor which is stored in time succession, in respect of the individual original bits, in a common quality factor memory. Quality factor differences of successive original bits are formed by means of a differencing means, and the quality factor differences of those original bits which have the same serial number within a reception bit are added by means of adding circuit. The maximum of the summed quality factor differences of n successive original bits is determined by means of a maximum decision circuit. The addresses of the original bits are continuously adapted in such a way that that of the original bit having the maximum summed quality factor difference receives a given, constant and predetermined value.