Abstract: In a local area network (LAN), of the Ethernet type, one of the segments, i.e. one bus, is replaced by a star coupler connected via optical fibre pairs to a number of stations. Each pair includes a GO fibre and a RETURN fibre. As in the usual Ethernet system, collision detection relies on measuring signal level on the medium, if it is too large then a collision condition exists.In an optical fibre system a similar collision detection technique is used. To detect collision, it is nescessary to be aware of the network's attenuation as "seen" by the station. To do this a low level pilot tone is sent from each station, each station having its own tone frequency. The amplitude of this tone when it returns to its own station indicates the system's attenuation, and this is used to detect collision.In an alternative the pilot signals are pseudo-random bit sequences.

Abstract: Two electrical-to-acoustical transducers (W1, W2) are attached to two contiguous sides of a cube (B) made of optically transparent material. The propagation directions of the two waves delivered by the transducers intersect inside the cube. The frequency of the light beam striking the device is shifted by f.sub.1 -f.sub.2, where f.sub.1 and f.sub.2 are the frequencies of the drive signals for the two transducers. The deflection of the light beam in the two propagation directions of the sound waves is proportional to the frequencies of the drive signals.

Abstract: An arrangement for the remote actuation of a controlled device, e.g. a hydraulic valve, in situations with stringent safety requirements, uses optical power. The optical power, e.g. from a high-power laser, is conveyed via an optical fibre (1) to the controlled device. Here it falls on a heat-absorbent surface (2), as a result of which a volatile fluid (e.g. freon) is evaporated. This via a bellows (4) drives an output rod (5), which operates the controlled device.Alternatives include a bimetallic strip, a thermostat-type capsule, and a memory metal strip, as the heat responsive device.

Abstract: The invention relates to a method of transferring information between microcomputers in a decentralized process control system, particularly for telephone systems. To prevent contention for possession of the information transfer bus without the need for central equipment, a simple bus system consisting of a multiwire data bus and two single-wire control buses is proposed. Bus mastership is passed on after transmission, with the address of the next transmitter being determined by each microcomputer itself and forming part of each message. Bus mastership is determined by communication of the previous transmitter and by calculations performed by the microcomputer itself.

Abstract: The correction filters which are used in manufacturing the structure of phosphor areas on the screens of color picture tubes are made more effective by being silvered or aluminized and provided with optical antireflection coatings. Owing to the resulting reduction of both the exposing and the cooling times, the number of lighthouses required for a certain production volume can likewise be reduced.

Abstract: To permit address-free fault location on digital communication paths with several intermediate repeaters, one or more identification signals must be recognized in the intermediate repeaters with sufficient certainty. The identification signals are digital signals with periodically recurring sections which are marked with a string of successive like bits (e.g., 0 bits) and have different durations for a first identification signal and a second identification signal.The circuit contains a time discriminator (1) which responds when a string of successively received like bits is characteristic of a section of an identification signal. It then provides a pulse equal in length to this section to a frequency discriminator (2) which responds when such pulses recur at a frequency characteristic of an identification signal. The frequency discriminator thus delivers an output voltage whose amplitude is typical of one identification signal or the other because of the different pulse durations.

Abstract: The invention relates to a supply circuit for a variable load, particularly for a line circuit in telephone systems.Conventional supply circuits, in which each of the two supply-current branches to the line wires contains the collector-emitter path of a transistor in series with an emitter resistor, offer a high AC resistance to voice-frequency voltages and longitudinal noise voltages, so that the bridging loss of the line remains small. To achieve a low AC resistance of the supply circuit to the longitudinal noise voltages, special measures in the control circuits of the transistors, particularly the use of a nonlinear element in the form of a CRD current-limiting diode in parallel with the controlled current path of each of the transistors, are proposed. These measures greatly reduce the amplitude of the longitudinal noise voltages at the inputs of subsequent circuits, which are thus protected.

Abstract: An electron-gun system is described in which the segments of the particularly long electrode neighboring the other electrodes are made of a material having a temperature expansion coefficient differing from that of the other electrodes.

Abstract: A sensor responsive to magnetic field strength employs a feedback control loop operating on a piezoelectric stretcher element (13) to maintain a predetermined phase relationship between the optical path lengths of first and second Fabry Perot optical fiber/waveguide interferometer cavities (4, 11) optically in series. The control signal for the loop is derived from monitoring the transmission of the series combination and compensates for changes in optical path length in one of the cavities, the sensor cavity (4), induced by a magnetostrictive stretcher (7). The arrangement is responsive not only to the magnetic field but also to spurious effects resulting from temperature changes and so a reference cavity (5) thermally strapped to the sensor cavity is employed in a similar configuration to provided a second signal for correction purposes.

Abstract: A telecontrol system is disclosed whose substations contain a control unit and plug-in interface modules for entering messages or measured values and delivering commands. Both the control unit and the interface modules are equipped with microcomputers and connected via suitable interfaces to a common serial data bus. Because of the presence of the serial data bus, the parallel buses of the microcomputers need not leave the individual modules, which reduces the susceptibility to interference on the buses. In addition, the serial data bus makes it possible to use any form of protection coding, so that individual modules can even be located away from the substation. Each interface module consists of an invariant portion, which is of the same design in all modules, and a problem-adapted portion, whose design depends on the task to be performed.

Abstract: A positioning device comprising a bolt having a transducer and an optical waveguide fixed inside a guide sleeve mounted concentric with the longitudinal axis of the bolt. Supporting members on the bolt for the transducer and the guide sleeve are arranged in a spaced relation. The supporting member for the guide sleeve comprises a semi-cylindrical shell provided with an extended supporting arm on which the sleeve is mounted. A plate-shaped supporting member for the transducer is mounted in the shell. To achieve an improved separation of the heat-flow paths, slots are cut on opposite sides of the supporting arm into the shell.

Abstract: In a stripe-geometry multimode laser having a current-flow-determining stripe, only the flow of electric current is confined to a narrow area, while the heat can flow off through a large area. A window for the flow of electric current is formed by a narrow epitaxial semiconductor stripe which, because of its high doping level and of additionally diffused charge carriers, is highly conductively connected to both the underlying semiconductor and the overlying metal, while next to the stripe, electric conductivity from the semiconductor to the metal is very poor. The thermal conductivity, however, is approximately the same over the entire area.

Abstract: A process for manufacturing a high voltage DMOS (Deep Diffusion Metal Oxide Semiconductor) transistor includes a first ion implantation and drive-in step to form a P-well in a N-substrate, and a second such step to form a N+ region in this well and a channel between this region and the substrate and under a polysilicon gate which is covered with a silicon nitride layer during the first step. By the presence of the latter layer pitting of the gate is prevented and no leakage paths are formed between source and drain.

Abstract: An electromechanical pulse generator includes a toothed disk driven by a rotating shaft to operate two pairs of contacts to generate one pulse output and one direction-of-rotation output. The pulse contacts and the direction-of-rotation contacts operate independently of each other. The toothed disk is rotatable and axially displaceable. The axial displacement is dependent on the direction of rotation via an inclined plane in the form of a screw thread which is rotatable by the rotary shaft. By axial displacement of the toothed disk, the direction of rotation of the shaft is detected, and by rotation of the toothed disk, the pulses are generated.

Abstract: A light-sensitive device is disclosed for separately detecting light of two different wavelength bands. Such a device can be used in optical data communication. The separate detection is accomplished by two separate pn junctions which are disposed on two different sides of a substrate and are optically in series. The pn junction lying in front in the light path responds to light of, e.g., 850 nm, but not to light in the range from 950 nm to 1,650 nm. The substrate acts as a filter and passes the light of longer wavelength while blocking the 850-nm light, so that the second pn junction is only reached by light in the range from 950 nm to 1,650 nm.

Abstract: A relatively shallow arrangement for providing illumination for a light scattering type display cell employs a transparent sheet in optical contact with the front surface of the cell and a matte black sheet out of contact with the rear surface. The assembly acts as a light guide for light launched into at least one of the transparent sheet from at least one strip lamp. The only light escaping from the display, etc. in the direction of the observer is a proportion of that scattered into non-guided directions by regions of liquid crystal layer selectively set into a scattering state.

Abstract: In a sensor head (1), hemispherical in form, a plurality of optical fibers (4) is uniformly distributed over the convexly arched surface area (3), and mounted therein. The other ends of the optical fibers (4) are gathered into a bundle (6) whose end face opposes a detector matrix (8) comprising a plurality of detectors. By a subsequently arranged evaluating circuit, and by assigning the detectors to the individual optical fibers (4), there is determined the direction and, by summing up the individual charges of the detectors, there is also recognized the intensity of the incident radiation.Some additional bundles (15) of optical fibers (16) are disposed by being distributed among the optical fibers (4). From each such bundle (15), an equal number of optical fibers (16) is led to each of several detectors (17). These detectors (17) are provided with individual filters (18, 19, 20) or a common filter (23) having certain wavelength responsive regions.

Abstract: Connection to a tantalum capacitor electrode (17) is effected using a conductive paint layer (15), incorporating pure silver and pure copper particles, which minimizes silver leeching by a tin-containing solder alloy (18) by which the lead wire (17) is connected to the conductive paint layer (15), and thus minimizes power factor degradation.

Abstract: In an optical transmission system in which a plurality of optical signal channels is multiplexed before transmission along a common optical path to a receiver, each channel is produced by means of a respective multimode injection laser, the overall cavity length of each laser being arranged to provide a multimode spectral output with a respective intermode spacing which differs from that provided by the other lasers for channel discrimination purposes. Comb filters are employed for demutliplexing.

Abstract: In addition to the correction magnets commonly used in the electron-gun system of a color-picture tube for color purity and dynamic convergence, one or more additional correction magnets are fixed in or on the electron-gun system. During final adjustment of the color-picture tube, the usual and additional correction magnets are adjusted in turn using the same magnetizer.