Abstract: A magnetic tape scanning unit comprising at least one stationary and one coaxial rotatable drum seciton (1, 2), and a rotary transformer (14) comprising two transformer discs (15, 16). One of the transformer discs (16) is mounted on rotatable drum section (2) by means of at least three sleeves (21) of weldable material which are open at one end and closed at the opposite end, the closed ends projecting from the drum section, the sleeves being mounted in angularly spaced axially parallel bores therein. Transformer disc (16) is provided with mounting elements having surfaces associated with the sleeves, and the closed ends of the sleeves (21) are welded to the corresponding mounting element surfaces. Assembly of a transformer disc on a drum section is achieved by supporting the drum section and the transformer disc in a jig in which the bottoms of the drum section sleeves are situated opposite and spaced from the associated transformer disc mounting elements.

Abstract: The invention relates to a tracking radar (17) rigidly connected to the fire tube (11) of a gun and controlling the set motors (14) of the gun in order to, after locking onto a target, cause the radar axis and thereby the axis of the fire tube (11) to follow the target. The invention the tracking radar (17) is contained in a protection envelope (20) which is fixedly mounted on the elevation system (12) of the gun and which at the front end in the fire direction is closed by a radome (21). The protection envelope (20) and radome (21) are dimensioned so as to withstand the forces arising at fire, in particular to prevent the compression waves then arising from deforming the antenna of the radar (17). The accuracy of the radar will thus be substantially maintained during firing of the gun.

Abstract: A receiver for measuring the amplitude of input amplitude modulated signals over an 80 dBm range and producing a digital output. The amplifier comprises a power splitter to which an input signal is applied via a limiter. First and second video detectors are coupled to the power splitter. In the case of the second video detector, an R.F. linear amplifier is connected in the signal path to provide an overall 40 dB's of gain relative to the input of the first video detector. Each video detector comprises a detector stage whose output is connected to an amplifier chain, each amplifier in the chain having a gain of 10. The outputs of the detector stage and amplifiers are quantized and applied to a logarithmic analog-to-digital converter. The outputs of the respective analog-to-digital converters are applied to a combiner.

Abstract: A display tube comprising an evacuated envelope having a display window, a conical portion and a neck, and an electron gun in the neck for generating an electron beam which is focused to form a spot on a display screen on the display window, the electron beam being deflected over the display screen in mutually perpendicular directions by pin-cushion-shaped deflection fields produced by a system of deflection coils. Field shapers are provided at the gun end of the tube which comprise two mutually perpendicular pairs of flat plates of ferromagnetic sheet material, the respective pairs of plates being arranged coaxially around the electron beam and respectively extending in the respective deflection directions. The plates are supported so that the gun ends thereof are at substantially the same distance from the electron gun, and cause the edge fields of the deflection fields to be barrel-shaped so as to prevent defocusing of the beam by the pin-cushion deflection fields.

Abstract: A frequency synthesized multichannel radio apparatus comprising a synthesized tranceiver and a remotely mountable control unit. All the possible channel frequencies available to users in a large geographical area are stored in a PROM mounted in the transceiver said PROM serving as a look-up table. The addresses of those channel frequencies in the PROM which are available to a particular user are stored in an electrically alterable storage means, such as an EAROM or a E.sup.2 PROM, contained in the control unit. In normal operation a channel selector in the control unit selects a particular channel in the electrically alterable storage means which in turn reads-out addresses of predetermined locations in the PROM which supplies data for example synthesizer divide numbers to the frequency synthesizer.

Abstract: A digital multiplex radio transmission system wherein transmission channels between a fixed radio station and a plurality of mobile radio stations may be established by code division multiplex or frequency division multiplex, individual message channels being separated by means of different distributions of the data symbols transmitted therein. In order to synchronize the fixed station transmitter with the mobile station receivers, respective synchronizing symbols are inserted between the successive data symbols transmitted in any channel. The synchronizing symbols used in all channels are the same, and are spaced at the same time intervals in each channel. Consequently, they are received with significantly higher energy than the data symbols, permitting the multi-path profile to be measured and providing reliable synchronization.

Abstract: A level indicator for displaying the decibel values of digital samples of an analog signal with respect to a reference value, each sample having a predetermined number of bits. The indicator comprises a shift register having a smaller bit capacity than the number of bits in the digital signals and for which, a resolution of 2dB, comprises three series-connected flip-flops. The digital signals are applied to the input of the first flip-flop and, together with the outputs of all the flip-flops, to a combinational logic circuit. The output of the last flip-flop is connected to a read-enable circuit. As each bit of a digital signal is shifted into the shift register, the logic circuit generates a logic signal from combination of the output signals of the flip-flops and such digital signal bit, the value of such logic signal indicating how many times a predetermined decibel amount should be applied to the value stored in the shift register in order to attenuate it to the reference value.

Abstract: A time switching method and apparatus for exchanging data words from a sequence of time slots in an incoming time-division multiplex frame to any other sequence of time slots an outgoing time-division multiplex frame. A data word in a given time slot s in an incoming frame is stored in a memory at an address A(s) which is equal to the number of time slots D.sub.j in an outgoing frame for which j is less than s and for which D.sub.j exceeds D(s). The data word already in the memory location address A(s) and the data words in addresses higher than that address are each shifted to the next higher address. Data words at memory addresses lower than A(s) are maintained at such addresses.

Abstract: Connection of a plurality of peripheral apparatus (APT) and a telephone station (PT) is achieved by a bus (BUS) which transmits analog signals and digital signals which are common to all of the apparatuses. Thus, each apparatus is supplied at each instant with information indicating the actual use of the telephone line to which the telephone station is connected.

Abstract: In a television signal memory write circuit which is synchronized by horizontal and vertical synchronizing signal patterns obtained from the television signal to be entered, the mutual positions of these patterns being measured with the aid of a measuring circuit; and depending on this measurement, the vertical synchronizing signal pattern is delayed by a variable delay circuit such that in practice the patterns are prevented from coinciding, thereby preventing a change in the position of a predetermined line number in the television signal memory circuit. This renders the circuit less sensitive to interference.

Abstract: An apparatus for playing optical discs is described, in which for a smoother locking-in of the focus servo control the focussing error signal is initially derived from the amplitude of the h.f. signal, followed by a gradual change-over to a difference signal derived by means of subdetectors. In this way the focus control point with the servo loop closed is shifted towards the desired in-focus point.

Abstract: For the decoding of a data stream which is word-wise protected against errors by a double Reed-Solomon code with symbol-wise interleaving over the code words, first the reliability information for the constituent symbols is aggregated for a code word. Therefrom the strategy is determined, entailing the number of erase symbols and the maximum number of error symbols to be corrected. The correction result is compared with a reliability code and on the basis thereof all symbols obtain an at least trivalent secondary reliability indication for decoding in the second code.

Abstract: A bulk diffuser for rear projection television screens which exhibits a Gaussian intensity profile. By appropriately selecting the indices of refraction of the substrate and the spheres therein and the range of diameters of the spheres, the intensity half-angle is made equal to the energy half-angle.

Abstract: A dispenser for launching radar deflecting elements from dispensing cassettes which are detachably supported in respective cells of the dispenser, each cassette supporting therein at least two cartridges containing the deflecting elements. Each cassette comprises guide means which cooperates with guide means in the cell in which it is inserted so as to correctly position the cassette therein, means cooperating with locking means in the cell to retain the cassette in such position, and means for electrically coupling firing pins of the cartridges to fire control means in the dispenser.

Abstract: With the aid of a traffic simulator telephone exchanges can be tested, the simulator imitating the traffic conditions in the exchange. To that end, the traffic simulator of the invention comprises, in addition to circuit means for simulating subscriber and line behavior, a program-controlled control arrangement connected thereto which generates random variables such as call distances, call durations and reaction periods, controls the test run and checks the reactions of the exchange, and also mixes the exchange-technical parameters. To obtain a realistic picture of the traffic conditions, a plurality of subscriber and line simulation are provided which are changeable in dependence on the reaction of the exchange. On the basis of the exchange reaction (signifying an event) a realistic picture of the external conditions of the exchange are obtained by linking such reactions with random variables and event instants.

Abstract: A transmit amplifier which also stabilizes the line direct voltage of the audio transmission circuit of a telephone set with respect to a reference voltage, the amplifier gain being adjustable to a high value by means of a resistor which does not affect the further properties of the audio transmission circuit. Variation of the line direct voltage by the offset current of the microphone pre-amplifier preceding the transmit amplifier, and by temperature fluctuations of the reference voltage, is greatly reduced by increasing the reference voltage and adding a temperature-dependent current source to a voltage divider which is comprised in the amplifier.

Abstract: The invention relates to a circuit arrangement for a home-entertainment apparatus which, by means of a memory and a timer, ensures that the apparatus can operate correctly only if a date has been entered. If this is not the case, the timer will disable the apparatus after a specific time interval.

Abstract: The noise-dependent volume control in accordance with the invention is capable of distinguishing between the real background noise and speech in a space (8). The gain (A) of the amplifier (1) is corrected only depending on the level of the background noise, so that once a difference in level between the background noise and a desired signal has been set this is maintained. The volume control is based on repeated measurements of the acoustic signal in the space (8). If it appears that in at least one frequency range the measured energy content (E.sub.i) has fallen at least N times within a range of values .DELTA.M around a value (M.sub.i) stored in a memory (26) the gain factor is adapted.

Abstract: A compact-disc-digital-audio-system has bandwidth reduced in order to extend the playing time, for example for the reproduction of 10 hours of speech. This is achieved without significantly modifying the existing players and without affecting the standard EFM coding, by multiplexing a plurality of information channels in such a way that they can be reproduced consecutively by repeatedly playing the entire CD disc.