Abstract: A clocked direct voltage converter with potential separation includes a control circuit for controlling the switching times of a switching transistor arranged on the primary side of the voltage converter, in which voltage converter voltage proportional to an output quantity is chopped by a controllable switch. The chopped voltage is transmitted by a transformer to the primary side of the converter, is then rectified, filtered and supplied to the control circuit. In order to obtain the largest possible control range for the converter, a further transformer is provided which transmits oscillation signal of an oscillator of the control circuit to the controllable switch on the secondary side voltage converter. By means of this oscillation signal, the controllable switch is controlled.

Abstract: A magnetic-tape apparatus comprises a deck (1) carrying the cylindrical drum system (3), which is provided with at least one rotating magnetic head (7). A supporting member (31) mounted on the deck (1) for rectilinear movement towards and away from the drum system (3) and has at least two mutually spaced tape guides (73 to 76) fixed thereto. By a movement of the supporting member (31) towards the drum system (3) a length of magnetic tape (84) is led to the drum system and is wrapped around a part of the circumference of the drum system. There is provided at least one positioning element (77) which forms part of a non-rotating drum section (4) which positions the tape guides (73 to 76) relative to the drum system (3) in the end position of the supporting member (31) by cooperating with projecting portions (31d) thereof.

Abstract: A class-G amplifier comprises first, second and third terminals connected to a load, first supply voltage (V.sub.1) and second supply voltage (V.sub.2), respectively, where V.sub.2 >V.sub.1. First (T.sub.1) and second (T.sub.2) transistors are series-connected between the first and third terminals with the collector of T.sub.1 coupled via first diode (D.sub.1) to the second terminal. A third emitter follower transistor (T.sub.3) has a B/E junction coupled between a signal input terminal and base of T.sub.1. A first current source (5) couples the third terminal and third transistor. A driver circuit includes a first current path between the third terminal and emitter of T.sub.3 comprising, in series, a second current source (7), a fourth transistor (T.sub.5) and second diode (D.sub.4). A second current path between a junction point (3) and common point (11) comprises, in series, third (D.sub.2) and fourth (D.sub.3) diodes and a third current source (8).

Abstract: A step-and-repeat electron image projector for transferring mask patterns repeatedly from a photoemissive cathode reticle (1) onto a target (3) with high resolution capabilities. Accelerated by a uniform electric field E and focussed by a uniform magnetic field H, a patterned electron beam is projected from the reticle (1) onto an area of the target with unity magnification. The electric field E is established between the cathode reticle and an electron permeable anode grid (2) situated between the cathode reticle and the target. Alignment of the beam and the target is effected by detecting electrons backscattered from reference markers (30) on the target with a backscattered electron detector (D) being located between the grid and the target. After exposing one area, the target is moved stepwise on an X-Y table (100) to expose an adjacent area, this procedure being repeated until the entire target has been exposed.

Abstract: NMR images formed by means of Fourier zeugmatography contain disturbing artefacts which are caused by coherent interference signals (for example, off-set signals, non-ideal 180.degree. reversing pulses). In accordance with the invention, an additional phase difference (.DELTA..phi.=.pi. in the case of even rows, and .DELTA..phi.=.pi.. (m-1)/m rad/sec in the case of m odd rows) is generated and the signal samples taken from the resonance signals are stored in adjacently situated rows of an image frequency matrix. The values in every second row of the matrix are changed to cancel said additional phase-difference, so that the contributions of the coherent interference signals to the matrix are influenced by the additional phase shift; if the additional phase shift is .pi. rad/sec, the values of every second row of interference signals in the direction of the columns are simply inverted.

Abstract: A switching stage receives two levels at its input, i.e. a high selection level and a low non-selection level. The Darlington stage (T.sub.1, T.sub.2) supplies at its output (E) a high current in the selected mode and a considerably smaller current in the non-selected mode. In order to accelerate the evacuation of charges accumulated in the base of T.sub.2 and hence the deselection time of the stage, an auxiliary current source (I), is connected to a point A. Between the base (B) of the transistor T.sub.2 and the point A two diodes (D.sub.1, D.sub.2) are connected in series in the forward direction. Between the emitter (E) of T.sub.2 and the point A a diode (D.sub.3) is connected in the forward direction. In the selected mode, the major part of the current I passes through D.sub.1, D.sub.2 and this current permits the evacuation of the charges from the base of the transistor T.sub.2 when the stage is deselected.

Abstract: An electronic D-type flipflop includes two storage elements and two transmission gates wherein each gate includes only one MOS transistor. In the first gate the MOS transistor is of a first conductivity type and it is of a second conductivity type in the second gate. The MOS transistors each receive the same clock signal at their gate electrode. Because it is not necessary to form an inverted clock signal, problems due to phase differences between the clock signal and its inverse are precluded. Each of the storage cells includes a pair of inverters which are coupled end-around. The transmission characteristic of the forward inverting circuit is adapted in such a way that it compensates for the voltage drop across the preceding transmission gate. Only a small substrate surface area will be required when the flipflop is used in an integrated circuit.

Abstract: A method of manufacturing a semiconductor device, in which there is applied to a surface of a semiconductor substrate a base layer of photosensitive lacquer, which is coated with a top layer of photosensitive lacquer. By means of a first patterned irradiation, there is formed in the top layer a mask of which a contact copy is formed in the base layer during a second irradiation. A material which can be discolored is used for the top layer. During the first irradiation, the top layer is locally discolored, whereupon the layer thus discolored is used as a mask during the second irradiation. By the use of the discoloring top layer, additional processing steps, which would ensure from a wet development of the top layer, are avoided.

Abstract: Television transmission or data storage system with time-division multiplex encoding. At least two signal sources are coupled via an encoding circuit for time-division multiplex encoding to a transmission or storage channel to which a data receiver including a decoding circuit can be connected. The signal supplied comprises two or more sub-picture signals during the line periods and the signal-compression or expansion time ratios for the different sub-picture signals are different. The decoding circuit is suitable for consecutively supplying signals during a line period of the data receiver, which signals largely correspond to the different sub-picture signals.

Abstract: An electrodeless metal vapor discharge lamp comprising a lamp vessel (1) which is sealed in a vacuum-tight manner and is further filled with a rare gas, which lamp is provided with a core (4) of magnetic material, in which a high-frequency magnetic field can be induced by means of an electric supply unit (7) and a winding (5) arranged to surround the core, an electric field being produced in the lamp vessel (1), the surface area of a cross-section orthogonal to the axis of the winding lying between 20 mm.sup.2 and 60 mm.sup.2, the lamp vessel (1) containing as rare gas krypton and/or argon at a pressure of at most 100 Pa, and the axial length of the winding lying between 8 and 15 mm.

Abstract: A thermal radiation detector comprises detecting means supported by a flexible film.To improve the absorption of incident radiation by the thermal radiation detector, the detector comprises an electrically resistive layer which is immediately adjacent the flexible film, and to which the detecting means are thermally coupled. The optical thickness of transparent dielectric material preceding the detecting means (suitably consisting only of the flexible film) is one fourth of a selected wavelength in a given wavelength range to be detected. The wavelength is selected so that the absorption of incident radiation by the resistive layer is substantially a maximum at the selected wavelength. The resistive layer may be between the flexible film and the detecting means, or it may precede the flexible film. In the latter case, an electrically conductive, reflecting layer is disposed between the flexible film and the detecting means.

Abstract: A printer having a printing head (3) which is secured to a holder (1) and which is movable in a reciprocating manner along an information carrier, the holder (1) engaging with resilient force a first roller (55) and a second roller (57). The rollers (55 and 57) move over two fixedly arranged roll surfaces (59 and 61), as a result of which a guidance substantially without friction of the holder (1) with the printing head (3) is obtained.

Abstract: An infrared intruder detection system has two separate channels A and B. Each channel has its own pyroelectric detector device and threshold level comparator. The comparator is responsive to dual polarity pyroelectric voltage outputs produced by the associated detector device as a result of an intruder-related infrared image moving thereacross. A logic circuit analyzes the comparator outputs and responds to the identification of particular intruder-indicative sequences of comparator outputs in both channels to generate an alarm and/or switching output. The logic circuit may also identify shock-induced comparator outputs. The system offers a high intruder detection capability with immunity from false triggering.

Abstract: A method of manufacturing a drawing die, in which a core of, for example, natural or synthetic diamond is clamped in the cavity intended for this purpose by deforming a tube which is made of, for example, a copper alloy to an annulus, the core being properly centered through the use of a rod-like member by means of which the core is pressed against the bottom of the cavity by a rod-like member having a pressure surface parallel to the bottom of the cavity during the deformation of the cylinder; in this way tilting of the core is precluded and it is not covered with material of the annulus in places where this is undesirable.

Abstract: A method of and an apparatus for providing a bubble-free coating on a fibre, more particularly on an optical fibre. A fibre to be coated is fed into a pressure chamber (61) via an inlet duct (56) with a restricted inlet opening (57) and leaves the pressure chamber (61) through an outlet opening (41) of a nozzle (40). Liquid coating material is supplied to the pressure chamber (61) at such a pressure that the coating material rises in the inlet duct (56) up to a certain level to form a convex meniscus (D). By flushing the surroundings of the inlet opening (57) with a gas having a kinematic viscosity which is lower than that of air, the drawing speed at which the applied coating is still bubble-free can be considerably increased.

Abstract: A digital-to-analog converter in accordance with the dynamic permutation principle in which a weighted series of accurate reference currents are generated by a cyclic permutation of currents which are equal to each other with a smaller degree of accuracy. The a.c. error component can then be eliminated by averaging the output signal of the converter over one full permutation cycle or an integral multiple thereof so that a signal without the error component is obtained by sampling at the end of every period. The setting of the digital-to-analog converter should not be changed during an averaging period.

Abstract: The invention relates to a high-frequency amplifier which comprises only two cascaded differential stages. The collectors of the transistors (T.sub.1, T.sub.2) of the differential input stage are connected to the emitters of two transistors (T.sub.3, T.sub.4) which have feedback between their collectors and bases and which are biased by means of resistors (R.sub.1, R.sub.2). This input stage forms a resonant circuit. The differential output stage comprises transistors (T.sub.6 and T.sub.7) whose emitters are interconnected by a phase-lead capacitor (C.sub.1) and two resistors (R.sub.8, R.sub.9). Such an arrangement enables a high gain to be obtained over the entire operating frequency range of the amplifier and in particular for high frequencies.

Abstract: The invention relates to an electrochemical cell having a negative electrode of a stable hydride-forming material, in which a high power density at a low temperature is obtained by adding from 5 to 45% by weight of LaNi.sub.5 or a comparable high-capacity material having a higher plateau pressure than that of the stable hydride-forming material.

Abstract: In communications systems, such as cordless telephone systems, in which synchronizing signals are transmitted at predetermined intervals on a signalling channel by base stations to say portable, battery-powered receivers, the need to send separate station identification signals is avoided by the synchronizing signals being transmitted from a base station in accordance with a predetermined signalling sequence, for example a pseudo-random sequence, and the receivers using the sequence as a base station identification signal.