Abstract: The invention relates to a crucible for growing epitaxial layers having a chemical composition formed by several chemical elements, of which at least one is volatile, by the method of epitaxy from the liquid phase, comprising an elongated support (72) on which a movable part (73) slides longitudinally, with the elongated support comprising at least one recess for accommodating a substrate (76) on which at least one epitaxial layer is to be deposited. The movable part (73) comprises at least one cavity (77) receiving a mother source (79) formed by initial material for epitaxy with the cavity having on the surface adjoining the elongated support a lower opening whose dimensions correspond to the dimensions of the substrates (76) present therein. At least one receptacle (80) accommodates a source for each volatile element of the chemical composition.

Abstract: In a transformer (1) comprising an E-I laminated core (2) with transformer windings (7) wound around the central limb (5), at least two metal-strip loops (10, 11) are provided for magnetic screening. The magnetic strips (10,11) extend around the corners (12) of the laminated core (2) at an as constant as possible distance from one another and perpendicularly to the lamination direction of the laminated core (2) and are welded (17) to the laminated core (2) at side areas where the magnetic field strength is low.

Abstract: In the method according to the invention conductive electrodes are provided with the aid of a mask aligned with respect to at least two contact windows present in an insulating layer. First, layers of metal combining with semiconductor material, for example, Pt silicide, are provided in the contact windows. A narrow region of the insulating layer between the two contact windows may have a reduced dimension because in their extreme relative positions the conductive electrodes can only partially cover the contact windows. The invention also relates to semiconductor devices comprising logic (or low-noise) transistors, or transistors for very high frequencies whose structure is improved with respect to their dimensions, their series resistance value and/or their gain.

Abstract: A method for converting m-bit information words into n-bit code words and vice versa. The code words have a limited disparity in order to obtain a d.c. free code. A reduction of the low-frequency content of the spectrum is obtained by selecting the code words in such a way that the sum ##EQU1## remains restricted over all the previously generated bits x.sub.j of the preceding code words.

Abstract: A semiconductor device has a surface zone which forms a planar pn junction with the surrounding substrate, this pn junction being biased in operation in the reverse direction. In order to increase the breakdown voltage, one or more floating zones are located beside the pn junction within the range of the depletion zone, which also form planar pn junctions with the substrate. According to the invention, the floating zones have an overall doping of at least 3.multidot.10.sup.11 and at most 5.multidot.10.sup.12 atoms/cm.sup.2, as a result of which they are substantially depleted at a high reverse voltage.

Abstract: Semiconductor devices including one or more gate-controlled unipolar hot-carrier transistors have a semiconductor barrier region located between laterally-separated first and second region portions of one conductivity type. The barrier region has a net doping concentration of the opposite conductivity type and is sufficiently thin such that the depletion layers formed at zero bias with both the first and second regions substantially merge together to deplete the barrier region of mobile charge carriers. Current flow between the first and second region is at least partially by thermionic emission of charge carriers of the one conductivity type across the barrier region at a major surface of the body. The transistor has a gate in the vicinity of the barrier region and capacitively coupled thereto (for example via a dielectric layer) so as to permit the thermionic emission current to be controlled by applying a voltage to the gate to adjust the effective barrier height of the barrier region.

Abstract: The invention relates to a single-channel digital communication bus system and to a station for use in such system. Only a single physical interconnection between the stations is present for transferring the data. Bit synchronization is effected either in that the data is self-clocking or by a second, clock lead. The data channel realizes an AND-function. The transmission of a message by a master station is answered by an addressed slave by an acknowledge signal train. The acknowledge signal train has a plurality of bits, inclusive of error protection bits. Error protection may be effected by transmitting a series of mutually identical bits, or by means of a CRC signal subtrain. The acknowledge may be positive, negative or a "no acknowledge" signal train.

Abstract: A method of and an arrangement for controlling a traffic control system comprising at least two measuring points located at a mutual distance along a traffic lane. It is determined whether the speed of a vehicle detected at one of the measuring points is less than a predetermined part of a running weighted average speed of vehicles detected in at least both measuring points. This has, inter alia, the disadvantage that a number of alarm signals are unnecessarily generated, which does not promote safety on the road. To obviate this it is determined at a measuring point, located downstream in the traffic direction, of the two above-mentioned measuring points, whether or not the speed of a vehicle detected there is less than a predetermined part of a running weighted average speed, which is exclusively determined from the vehicle speed detected at the upstream measuring point of these two measuring points.

Abstract: In a two-way radio transmission system, a fixed base station transmits and receives over at least one communication channel a plurality of messages for different types of receivers (TGAx) used in different services (DY). The base station transmits an organization data flow identifying the message type (TGAx) and services (DY). A plurality of different subscriber transmitter receiver sets receive each message type (TGAx) and transmits messages to the base station. The receiver sets decode the organizational data flow, and process only those messages and services which are associated with a given message and service type. In this way, different classes of communication services may be offered, using a common base station.

Abstract: A DC-AC converter for igniting and supplying a low-pressure discharge lamp, e.g. an electrodeless low-pressure gas discharge lamp. The converter has two input terminals (9, 10) for connection to a d.c. voltage source. The input terminals are connected to a series arrangement controlled semiconductor switching element (12), a first coil (14) and a parallel circuit having the discharge lamp 15 in one of its branches. The control electrode and a main electrode of the controlled semiconductor switching element are connected together by means of a secondary winding (21) of a transformer (17) having a primary winding (16) that forms a part of the parallel circuit. The converter includes a starter circuit comprising a resistor (28) connected between a main electrode and the control electrode of the semiconductor switching element and a capacitor (29) coupled between the control electrode and one end of the secondary winding (21) of the transformer.

Abstract: A pseudo-random binary sequence generator comprises at least one shift register (S, T) arranged in a recirculating loop and having a plurality of logic gates (G) for logically combining the outputs of selected stages of the register to provide a pseudo-random sequence, and a multiplexer (M), having a p data inputs and q address inputs all connected to selected shift register stages, and which selects at any instant one of the p data input bits in accordance with the q-bit address word to provide the generator output. The number s of logic gates is especially high and is related to the total number r of shift register stages (r>p+q) by the expression: 2.sup.s .gtoreq.r.sup.2. Some of the shift register stages of the or each shift register are connected to selected data inputs of the multiplexer and others of the stages of the same shift register are connected to selected address inputs of the multiplexer.

Abstract: A flat color selection electrode is tensioned on a supporting frame. In order to compensate for differences in thermal expansion between the supporting frame and the color selection electrode and mislanding, spring constructions connect the supporting frame and the color selection electrode and permit only a maximum tension at the color selection electrode which is smaller than the elastic proof stress of the color selection electrode. Such a color selection electrode may be used in a color display tube having an at least substantially flat display screen.

Abstract: Luminescent rare earth metal phosphate defined by the formulaLn.sub.14-p-x Tb.sub.p Me.sub.x P.sub.6-y Al.sub.y O.sub.36-1/2x-ywherein Ln is yttrium which may be replaced up to 50 mol % by Gd and/or La, wherein Me is at least one of the elements Ca, Sr and Ba, and wherein 0.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.1.5 and 0.1.ltoreq.p.ltoreq.4 is disclosed. The phosphate is useful in a luminescent screen and low-pressure mercury vapor discharge lamp provided with such a screen.

Abstract: A power supply circuit in which the mains voltage which is applied across the primary winding (2) of a transformer (1) to generate a first direct voltage across a first capacitor (C.sub.1) by means of a secondary winding (3) and a first rectifier (D.sub.1) and a second direct voltage is generated across a second capacitor (C.sub.2) by means of a tertiary winding (4) and a second rectifier (D.sub.2). If the mains voltage is not connected, a first direct voltage is supplied by a battery (15) connected in parallel with the first capacitor (C.sub.1). The second direct voltage then is generated from the battery voltage of the battery (15) by means of an inverter circuit (20), a transistor (T.sub.1), the secondary winding (3) and the the tertiary winding (4).

Abstract: An optical scanning unit with an objective for focussing a beam into a scanning spot on the surface of an information carrier and an electromagnetic drive for continuous correction of the position of the objective with respect to the information carrier. The objective is mounted in a movable ring-shaped magnetic body of a permanent-magnetic material which is arranged coaxially about the optical axis and which has magnetic poles at the axial ends. The drive is provided with sets of fixed coils which interact with the magnetic body via an air gap. Each set of coils has a first segmental coil arrangement having two active coil parts extending parallel in the peripheral direction of the magnetic body and located in the vicinity of the axial ends of the centrally positioned magnetic body. The unit is further equipped with at least one second coil arrangement which is positioned at least partially between the active coil parts of the above-mentioned first segmental arrangement.

Abstract: Coma correction means is provided in a color display tube including an evacuated envelope (1) containing an electron gun system (5) of the "in-line" type to generate three electron beams (6, 7, 8) situated with their axes in one plane. The electron beams converge on a display screen (10) provided on a wall of the envelope and are deflected over the display screen in two mutually perpendicular directions by means of a first and a second deflection field. The first deflection field is parallel to the plane. The electron gun system includes at its end field shapers (34, 35) for causing the frames described on the display screen by the electron beams to substantially coincide the field shapers include substantially annular elements (34) of a material having a high magnetic permeability around the two outermost beams. Two elongate flat strips (35) of a material having a high magnetic permeability are provided symmetrically with respect to the axis (37) of the central beam and the plane through the beam axes.

Abstract: A circuit arrangement for A.C. operation of gas discharge lamps comprises a full-wave rectifier (1) connected to an alternating voltage source. The direct voltage is supplied to a combinatorial circuit part (3 to 8) in the form of a direct voltage converter, to which is connected a bridge circuit (9) which comprises four thyristors. The transverse branch of the bridge circuit includes the lamp (5). The full-wave rectifier (1) is followed by a smoothing capacitor (2) and an electronic switching element (14) is connected parallel to the bridge circuit (9). The switching element is switched to the conducting state in the vicinity of the zero passages of the input alternating voltage. As a result shortcircuits in the bridge circuit are avoided.

Abstract: A multi-phase brushless d.c. motor comprises a permanent-magnet rotor (1) and a stator (2) with stator coils (16, . . . , 21) arranged between three power lines (A, B, C). For the purpose of commutation the motor is provided with switching devices (22A, 22B, 22C) for the cyclic disconnection and connection of the power-supply lines (A, B, C) of the motor to a d.c. power source (25). Each switching device (22) comprises a section (42) which is controlled by the rotor-magnet field for deriving the disconnection instants and a section (43) for deriving the connection instants from a voltage change which is produced on the power-supply line connected to the switching device as a result of another power-supply line being disconnected.

Abstract: The invention relates to a tunable magnetron comprising a rotatable tuning element (10) projecting into a ring shaped interaction space between coaxially arranged cathode and anode systems. The tuning element (10) is driven by an electric motor (11) and produces upon rotation a periodic variation of the tuning. The tuning element (10) is situated within the evacuated space of the magnetron and the motor (11) in situated outside said space. The drive torque of the motor is then transferred to the tuning element via a coupling (12) having two active parts situated one on each side of the evacuated envelope (17) of the magnetron. Such a coupling can only transfer a limited torque. According to the invention the magnetron comprises means for limiting the torque which can be transferred to the coupling (12), both upon starting and stopping, for example a torque limiter (21-26) between the motor (11) and the coupling (12), whereby the start and stop procedures can be performed with optimum torque.

Abstract: A flat cathode ray display tube has an envelope divided into front and rear portions by a partition carrying frame deflection electrodes with an electron gun (30) and line scanning deflector positioned in the rear portion, the electron beam being directed initially parallel to a flat faceplate of the envelope, turned through 180.degree. by a reversing lens into the front portion and then deflected by electrodes towards a screen on the faceplate. In addition to the electrodes, other components are also mounted on the partition forming a sub-assembly whereby correct mutual positioning is ensured and assembly facilitated. A spacing structure accurately spaces the sub-assembly from the faceplate and supports also an electron multiplier for beam current amplication.