Abstract: A structure with fine details, such as a periodic signal, is displayed on a raster display. To avoid aliasing due to an interference between the details and the columns and row pattern of the raster display each of the points representing the structure to be displayed is allocated to pixels in adjacent columns and/or rows. Allocation occurs by means of a stochastic procedure in which the probability to allocate a point to a pixel is dependent on the position of the point with respect to the pixel. Accumulated pixel-values are converted into a limited number of grey-values by means of an additional procedure that allows for fixed proportions of the pixels to have the same grey-value.

Abstract: In a data processing system including a graphic tablet and a wireless stylus cooperating with the tablet, the stylus transmits an electromagnetic field to be received by the tablet. The stylus has a detector whereby a disturbance of the field, caused by a means external of the stylus, can be detected. The stylus also includes a switch whereby the stylus can be switched to a power-saying standby mode in response to the disturbance. A contactless on/off switch is thus realized for the stylus.

Abstract: The invention relates to a high-pressure discharge lamp provided with a discharge vessel which encloses a discharge space, which has a ceramic wall, and which is sealed at one end by means of a projecting ceramic plug which encloses with clearance a current supply conductor to an electrode arranged in the discharge vessel and is connected to said conductor adjacent an end facing away from the discharge space in a gastight manner by means of a melting-ceramic connection. According to the invention, at least an end portion of the ceramic plug situated near the end facing away from the discharge space is impermeable to light.

Abstract: A data processing apparatus includes a unit (60,68) for modelling a first asynchronous logic circuit as a plurality of circuit elements the functions of which are governed by a set of rules each defining a response to a given condition. For elements functioning as registers, units are provided to apply a constraint (for example an algebraic or Boolean relationship) linking the internal values or output states of two or more of the registers. In response to a change in the internal value or output state of one of the registers, the corresponding one of the internal value or output state of the or one of the other registers is modified to maintain validity of the constraint. Each of the registers has a pointer (VP) to a respective data value or constraint information held in storage (67).

Abstract: A circuit arrangement calculates pseudo-random permutations of a set of numbers. Including compositions of some basic pseudo-random permutations and the inverse permutations of permutations that are calculated. The basic pseudo-random permutations, their compositions and inverses are all calculated by the same generator whose operation is commanded to calculate the appropriate permutation by specifying a set of integer coefficients f.sub.i. The generator calculates the permutations .sigma.(n) of the numbers n=0 . . . m-1 corresponding to ##EQU1## where .alpha. is an integer number which is divisible by all prime factors of m and by four if m is divisible by four, with a potency s(.alpha.) of two or higher. When the same a is used for all permutations it is assured that all compositions and inverses of the generated permutations can be calculated in the same way, by the same generator.

Abstract: A record carrier, a playback apparatus and a system including the record carrier and the playback apparatus. Information has been recorded on the record carrier in the form of variations of a first physical parameter. The playback apparatus scans the record carrier by means of a transducer which is responsive to the variations of the first physical parameter. An information recovering circuit recovers the information from a detection signal received from the transducer. The record carrier exhibits second variations of a second physical parameter, which differs from the first physical parameter, but which second variations are of a type that are detectable by the transducer. A detection circuit detects the presence of a predetermined property of the second variations (e.g., that the second variations exhibit a modulation pattern representing a code) on the basis of a detection signal received from the transducer.

Abstract: A radiation beam is generated by a radiation source such as laser. An optical system focuses the radiation beam at a recording layer (in a disc-shaped carrier) of a type in which an optically detectable change is caused to take place if the recording layer is heated to above a write temperature. The recording layer is scanned by the radiation beam by means of a motor. A control circuit feeds the radiation source with electric power which is converted in the radiation source partly into heat and partly into radiation for the radiation beam. The control circuit operates in a read mode in which the power supplied to the radiation source has a value at which the rise in temperature of the recording layer caused by the radiation beam is insufficient to cause an optically detectable change to take place.

Abstract: A local network for connecting a plurality of stations includes a main ring which is formed by a number of network interfaces coupled via main ring lines, which network interfaces are each coupled to a respective one of the stations, and a first relief ring, which is formed by a number of bridge elements coupled in series via relief ring lines. The relief ring is coupled to the main ring. At least one bridge element is provided for establishing a connection between the first relief ring and the main ring.

Abstract: A colour display tube has an in-line electron gun for generating three co-planar electron beams first and second lens electrode produce a focusing lens field for focusing the electron beams. At least one of the lens electrodes has a correction element for tuning the astigmatism of the lens field. The correction element includes three co-linear apertures for passing the electron beams, the outer apertures of which are funnel-shaped, the wide end of the funnel-shape being directed away from the center aperture.

Abstract: An optical information storage system has a multi-recording layer record carrier and a scanner device for the carrier. The scanner produces a radiation beam which is compensated for spherical aberration for a single height of the scanning spot with the stack of layers. The height of the stack is determined by the maximum spherical aberration permissible for the system. The number of layers in the stack is determined by the minimum distance between layers, which depends on the crosstalk in the error signals due to currently unscanned layers.

Abstract: A method of selecting low-pressure mercury discharge lamps comprising a luminescent layer, the luminescent layer being excited and the low-pressure mercury discharge lamps being selected in dependence on the emission spectrum of the visible light emitted by the luminescent layer. The luminescent layer is excited by a light source arranged outside the low-pressure mercury discharge lamp and which generates ultraviolet radiation having a wavelength above 300 nm. This makes it possible to use the presence of a blue-luminescent substance in the luminescent layer as a selection criterion for both leaky and intact low-pressure mercury discharge lamps.

Abstract: An optical communication system includes a directly modulated semiconductor laser (10), the output of which results in pulse shortening of light pulses corresponding to high level bits of a high frequency electrical digital modulating signal. A travelling wave laser amplifier (14) coupled to the laser provides an amplified modulated light signal to an optical channel (16), and an optical detector (18) converts a light signal received from the optical channel into an electrical signal. The amplifier has an overshoot characteristic which provides an extended output when overdriven by a high level optical input pulse, and the modulated laser is arranged to provide such high level pulses. The overshoot characteristic of the amplifier thus compensates for pulse shortening produced by the modulated laser in the case of isolated high level bits and the initial bit of a stream of high level bits. The invention also relates to a transmitter and to a repeater for use in such an optical communication system.

Abstract: A semiconductor device is provided with an organic material which is formed by a solid-state mixture of organic donor and organic acceptor molecules. A semiconducting solid-state mixture is known with molar ratios between donor and acceptor molecules of 1.3:2 and 1.66:2. The known solid-state mixture has the disadvantage that its electrical conductivity is comparatively high, so that it is not possible to manufacture switchable devices from the mixture. Here the material includes an n- or p-type semiconductor material, the n-type semiconductor material having a molar ratio between the donor and acceptor molecules below 0.05, and the p-type semiconductor material having this ratio above 20. These solid-state mixtures may be used for manufacturing switchable semiconductor devices. The n- and p-type organic solid-state mixtures can be used for manufacturing transistors, diodes, and field effect transistors in a same manner as, for example, doped silicon or germanium.

Abstract: A method of manufacturing a programmable semiconductor element in the form of an anti-fuse, comprising a thin layer of silicon oxide between two electrode regions, such that a connection can be formed between these electrode regions through electric breakdown in the oxide. In the method, a nitrogen implantation is first carried out at the area of the oxide to be formed, so that a thin layer comprising nitrogen is formed at the surface, which has an oxidation-decelerating effect. Then the oxide is provided through thermal oxidation. Owing to the oxidation-decelerating effect of the layer with nitrogen, an extremely thin oxide layer, for example 5 nm thick, may be obtained in a reproducible manner in a sufficiently long oxidation time.

Abstract: In the market, there is a tendency towards picture tubes with a super flat screen. Due to the flat screen, it is becoming increasingly difficult to meet the even tighter specification on North/South raster distortion (N/S distortion), the tighter specification being caused by a growing importance of text display and high resolution displays. A deflection correction circuit is provided which compensates for a N/S distortion by inducing a correction current (Icv) through a vertical deflection coil (Lv). The correction current (Icv) can be injected in the vertical deflection coil (Lv) via an injection transformer (Ti) coupled in series with the vertical deflection coil (Lv). The injection transformer (Ti) is driven via an output stage (3) by a waveform generator (1,2). The waveform generator (1,2) generates a voltage waveform (M) built up out of substantially straight line sections. The deflection coil (Lv) integrates the voltage waveform (M) into a current waveform (Icv) having substantially parabolic sections.

Abstract: In a communication system comprising different apparatuses which are coupled together by a bus, a control instruction, for example, a remote control command may be passed on by a plurality of apparatuses to the apparatus performing the instruction. In order that the apparatus performs such an instruction only once, the control circuit in the apparatus memorizes from which source the performed instruction has been received. The identical control instructions received from the other apparatuses are ignored for a predetermined period of time.

Abstract: An electromagnetic deflection unit (5) comprising a coil holder (6) with a flange (8) whose inner side supports coils (10a, 10b) for (line) deflection of electron beams. At the flange side of the coil holder (magnetized) preformed elements (14) are arranged within these coils so as to influence the magnetic field of these coils (10a, 10b), thereby reducing spreading errors, caused during manufacture, throughout the display screen. For the purpose of automatic mounting of the preformed elements, an annular support having predetermined locations (in particular from 12 to 36) for accommodating preformed elements is used. The preformed elements (14) are accommodated at a plurality of these predetermined locations and, if made of a permanent magnetic material, produce magnetic fields having magnetic strengths measured at a distance of some mm above the heart of the elements in the range between 1 and 1000 .mu.T.

Abstract: The electric lamp has a lamp vessel (1) having seals (4, 5) onto which respective bases (20, 21) are secured. Each base comprises a cylindrical insulator body (22) in a free end of which a contact member (30) is accommodated, having a contact face (31) and a protruding portion (33) which has a connection area (32) to which a current supply conductor (8) of the lamp is secured. The contact member (30) is a body made from metal foil.