Abstract: A liquid crystal display cell having a compensation layer of (polymer) material deposited from the gaseous phase. To obtain a smaller angle dependence, the birefringence of the compensation layer is rendered complementary to that associated with a given voltage across the liquid crystal cell by giving the optical axis of the compensation layer an angle to the direction transverse to the cell.

Abstract: A semiconductor device for microwave frequencies with a substrate which is provided at a first side with a semiconductor element, a passive element, and a pattern of conductive elements, while the opposed, second side is provided with a metallization which is connected to the elements present on the first side through windows formed in the substrate. The substrate consists of a silicon layer which is present on a layer of insulating material, the semiconductor element being formed in the silicon layer, and the metallization being provided on that side of the layer of insulating material which is remote from the silicon layer. The silicon layer may here have a very small thickness of, for example, 0.1 to 0.2 .mu.m. In such a thin silicon layer, bipolar and field effect transistors capable of processing signals of microwave frequencies can be formed. Since the silicon layer is thin, the influence of the conductivity of silicon on passive elements is small.

Abstract: A signal processing system comprising a source apparatus coupled to a destination apparatus, the source apparatus being arranged for supplying the destination apparatus with a signal comprising video data, a time-stamp and synchronization data representing a time-value of an instant of said supplying, the destination apparatus being arranged for receiving the signal, synchronizing a time-value of a clock in accordance with the synchronization data, detecting when the time-value of the clock corresponds to the time-stamp and for thereupon presenting the video data at an output. The system includes a bus operable according to a time-slot allocation protocol, the source apparatus supplying the signal to the destination apparatus via the bus, the source apparatus including a first interface unit for buffering the signal until an allocated time-slot is available on the bus, the source apparatus setting the synchronization data according to an instant the signal is supplied to the first interface unit.

Abstract: A method and apparatus is disclosed for determining a masked threshold curve as a function of frequency from an information signal.

Abstract: A controller for supplying a switching drive voltage signal to a semiconductor power switch includes a wave-shaper circuit that generates a piece wise linear (PWL) waveform that slows the rate of change of the drive voltage supplied to the control electrode of the semiconductor power switch. As a result, the radiated electromagnetic interference generated by the apparatus can be appreciably reduced.

Abstract: The invention relates to an optical switch which is switchable by means of light. The switch includes a directional coupler having four gates, the first gate of which forms part of an input of the switch for receiving an optical data pulse series, the second gate forms part of an output of the switch and the third gate and the fourth gate are interconnected by means of a waveguide structure. This waveguide has a non-linear optical portion at an asymmetrical position in the waveguide. A control pulse signal is also introduced into the waveguide via the first gate of the directional coupler. The waveguide is asymmetrical for the data pulse series and symmetrical for the control pulse signal.

Abstract: A method of manufacturing a device provided with a body with a surface, at least a portion of the surface being provided with a radiation-sensitive layer, after which portions of the radiation-sensitive layer are exposed to radiation through a mask, a first portion of the layer being irradiated directly using a first part of a radiation beam projected through the mask and a second portion of the layer being irradiated indirectly using a second part of the radiation beam projected through the mask and reflected onto the second portion, the radiation beam being substantially collimated.

Abstract: Circuit for multiplying data in accordance with a Booth algorithm, in which the coding of the control signals is adapted to the characteristics of symmetry of a trigonometric function. The values of the function which relate to a single quadrant are stored in a memory and a converter unit makes it possible to utilize the circuit whatever the quadrant. The values of the trigonometric function may be obtained through interpolation. Application to the calculations of Fourier transforms or DCT transforms.

Abstract: A record carrier on which a first information volume and an additional information volume are recorded. The first information volume includes audio information, preferably recorded in accordance with the Compact Disc Digital Audio standard. The additional volume includes additional non-audio information related to the audio information recorded in the first information volume. The additional volume also includes control information for searching for information in both the first and the second information volumes. A dedicated data reading apparatus for such a record carrier firstly accesses the additional information volume. On the basis of the control information, the dedicate data reading apparatus can also access the audio information in the first information volume. An audio reading apparatus which can not handle the additional non-audio information automatically accesses the first information volume.

Abstract: The linear guide arrangement comprises two bodies having respective guide surfaces. The guide surfaces face one another and are spaced from one another by two parallel rollers. The rollers are positioned by means of a number of steel bands secured to the bodies.

Abstract: Transmitter station for transmitting, and receiver for receiving a plurality of television programs via respective transmission channels. A teletext page with tuning data (F) which are representative of the transmission channels used by the transmitter station is transmitted by means of one of the programs, for example a local television program. Moreover, further signal processing data are incorporated in the teletext page, which data are representative of the transmitted television programs, such as a station name (NAM), a system code (S) and a predetermined teletext page number (PDC). When the television receiver is tuned to a television program, the respective signal processing circuits are controlled by means of the corresponding signal processing data.

Abstract: An electrical actuator comprises a first actuator body (1) and a second actuator body (3). The first actuator body comprises two diametrically opposed magnetic poles (N) and (S). The second actuator body is made of a soft-magnetic material and comprises three inwardly directed radial teeth (19, 20 and 21). In order to obtain a maximal ratio between the delivered torque and the applied electric power, only two teeth (19 and 21) are provided with exciter coils (29 and 31). In order to minimize detent torques the three teeth are identical to each other and the first actuator body is suitably diametrically magnetized.

Abstract: A technique for making a microwave, high power SOI-MOFET device is set forth together with such a device. An important aspect of this structure is the presence of high conductivity metal gate fingers for the device.

Abstract: A method for manufacturing a ridge in a channel laser diode in II-VI materials by etching grooves to form an active mesa flanked by support mesas. The method involves using certain etchants for certain compositions of the II-VI layers so that the grooves can be formed by wet chemical etching using only a single photolithographic process.

Abstract: Apparatus and methods for transmitting and receiving a digital data signal. At the transmitter side, packets of p m-bit digital words in a digital signal are error protection encoded to produce error protection encoded packets of n m-bit digital words making up an error protection signal, where n>p. The error protection encoded packets are converted into converted packets of digital words to form a channel encoded signal, which signal is supplied to a transmission medium. The conversion involves use of a generator for supplying a fixed auxiliary packet of n digital words; a calculation unit for calculating in a Galois field GF(2.sup.m) a converted digital word in accordance with the formula DW.sub.i +.alpha..FW.sub.i, where DW.sub.i and FW.sub.i are the binary values corresponding to the i-th digital words in the packet to be converted and the auxiliary packet, respectively, .alpha.

Abstract: The invention relates to a position sensor including at least two sensor units which measure in a contactless manner a position x of an element which is movably arranged relative to the sensor units. Using limited circuitry, the invention precludes sources of errors during the processing of the sensor signals in that from the sensor signals there is formed a measuring signal from the phase position of which relative to the clock signal there can be determined the position x. The position x may be, for example an angle or a length position.

Abstract: A current memory for balanced current inputs comprises two coarse and two fine current memory cells each of which comprises a field effect transistor having a switch between its gate and source electrodes. Parasitic gate-drain capacitances are neutralised by capacitors connected between the gate and drain electrodes of opposite pairs of transistors. Other current transport errors can be compensated by providing appropriately dimensioned extra capacitance added to each of the neutralising capacitors.

Abstract: A device for processing digital data comprises a memory, error detection means and control means which selects addresses for the writing of the data in the memory on the basis of errors detected in the data, and which selects further addresses for the reading of data from the memory. Thus, only reliable data is read so that a high picture quality is achieved in a digital video system, despite the presence of errors in the data.

Abstract: A power amplifier stage for producing a rectangular signal across a load, which may be predominantly capacitive, by means of a "bridge" amplifier comprises a first pair of transistors which operate alternately as an emitter follower and a second pair of transistors which alternately closes the circuit of the load. The four transistors of the bridge amplifier are respectively driven by identical four current sources in order to minimize the impedance of the circuit of the load for direct current. The transistors of the second pair are alternately connected as diodes. To control the signal amplitude, a generator supplies a control voltage whose value corresponds to a fixed component equal to 2.V.sub.BE, plus a variable component corresponding to the desired amplitude of the signal. Such a power amplifier stage can be used for driving a piezo-electric transducer, particularly for a telephone bell.

Abstract: A recording and/or reproducing apparatus comprising a guide roller for guiding and diverting a magnetic tape. The guide roller includes a roller member, which is rotatably and pivotably mounted on a shaft, and a guide flange for the magnetic tape, which guide flange is disposed near the shaft bearing location, the lower edge of the magnetic tape being pressed against the guide flange. In order to reduce the force exerted on the lower edge of the magnetic tape a stationary roller member is interposed between the rotatable roller member and the guide flange, and the two roller members are movable relative to one another in the direction of the bisector of the wrapping angle of the magnetic tape.