Abstract: Method for controlling an antenna of an earth station for telecommunication via satellites, which antenna is provided with means to determine the position of the antenna and with means to ascertain the strength of the received signal, the direction of each change of position to be made by the antenna being derived from the change of the signal strength and the attendant change of position in consequence of the uncontrolled changes of position made by the antenna with respect to the position chosen.

Abstract: Method and device for extracting a synchronizing signal from a digital signal. The synchronizing signal can be a single bit, a word or a subframe. A first circuit searches for the synchronizing signal in a fixed position in the received signal every time it should occur. If this circuit does not find the synchronizing signal when it should, a second circuit starts a search action for it in the received signal. When the first circuit has not found the synchronizing signal a fixed number of times, the loss of synchronism will be signalled to the equipment that follows. If in the mean time the second circuit has found the synchronizing signal a fixed number of times in the same position in the received signal, then the first circuit will be synchronized with the second circuit. This synchronism only occurs if the second circuit has found the synchronizing signal a greater number of consecutive times than the first circuit within the same period of time.

Abstract: Belt type conveyors for letters and the like, having a switching device between them, which device comprises a roller having a flattening on its circumference i.e. a segmented roller, driven by means of a one-rotation coupling when a letter is sensed on the conveyor approaching the switching device.

Abstract: Method and device for eliminating the background brightness variation of a video signal, in which the background brightness in each line of the frame of a video signal has its low frequency brightness signal a(t) limited, as well as being limited by its deviation from the limited brightness of the preceding line of frame. This can be expressed mathematically by stating that .vertline.V(t)-a(t).vertline. is minimized by means of a(t) on the marginal conditions.vertline.a(t)-a(t-T).vertline..ltoreq..epsilon. and.vertline.a(t)-a(t-.DELTA.).vertline..ltoreq..epsilon.,in whichV(t)=the video signal V at the moment t;a(t)=an estimation of the background brightness variation a(t);T=the duration of a line;.DELTA.=h/b T/k, in which h/b=the height/width ratio of the image and k=the number of lines per frame, and.epsilon.=the maximum value of the derivative of a(t) multiplied by .DELTA..

Abstract: Device for protecting electric systems, particularly telecommunication systems, against overvoltage, comprising the combination of a tube of conducting material and permitting a passage through the wall with an overvoltage protective circuit placed in the tube and comprising at least two diverting components, in such a way that a voltage peak, even with a steepness of 5kV/nsec, can be diverted step by step.

Abstract: Optical reading head, particularly for reading luminescent code bars on documents and the like, which reading head is provided with a source of light for irradiating the bars, with a detector including a hollow optical guide means for collecting the rays emitted by the bars, said guide means being made of a filter material transmitting ultraviolet radiation at least at the end of said guide near the point where the rays are collected.

Abstract: Filter chain comprising at least two cascaded duals, each provided with two acoustically coupled resonators, only one of the two resonant frequencies of each of the duals falling within the filter pass band; the duals are convex at least on one side so as to render the acoustic coupling between the resonators so strong that the distance between the two resonant frequencies of the dual is as great as possible.

Abstract: Calculating device provided with scales for calculating radioactive doses and intensities, in which the scales are arranged for calculating the product of the intensity in a radioactive area at a given instant and a dose factor to be determined by experiment. This dose factor depends on the moment when the contaminated area is entered and on the time spent in the area.

Abstract: Method and device for transmitting binary signals by means of digital self-synchronizing scramblers, the information of the storage elements used being utilized, in combination with that of the input signal, for detecting the degenerative condition of a long series of identical bits.If the said condition is still existing after a number of consecutive clock periods, a change is made in it by inverting one bit of the input signal.The detection and the inversion also take place at the receiving end, thus ensuring an unerring working of the system.

Abstract: A system for reducing the time for repeating erroneous signals through a series of interconnected ARQ-circuits (automatic error correction circuits), in which the durations of the repetition cycles of the ARQ-circuits, as compared to one another, are not equal. The system comprises means at a connection point and capable of storing a number of signals related to each propagation time of a circuit located before the connection point, when a circuit located behind the connection point goes through a repetition procedure including means for generating a special signal to indicate when a repetition procedure is in process in one of said ARQ interconnected circuits to prevent the other interconnected ARQ circuits from also going through their repetition procedures.

Abstract: A printer, comprising a printing element which, when in operating position, is placed in a magnetic field, and is connected to a secondary winding of a transformer. This transformer has two additional secondary windings and two primary windings which are connected to a circuit so arranged that after a start pulse, two current pulses of opposite directions are successively supplied to the transformer of which only the second pulse effects movement of the printing element. The two primary windings are each connected to an amplifier, each of which supplies one of the current pulses. The input of the circuit and the amplifiers are coupled in such a way that the start pulse controls one of the amplifiers which in turn, through the two additional secondary windings and a blocking circuit, controls the other amplifier to produce the second pulse.

Abstract: Method for detecting, in a combined digital signal, the presence of two signals differing in frequency, amplitude and phase and having frequencies occurring in a known series. Samples of the combined signal are multiplied by samples of only one derivative of each of the frequencies of the known series. This derivative is formed by the product of a modulating factor formed by the samples of a frequency which is the sum or the difference of (a) a fixed frequency of 2000 Hz and the frequency to be detected in the known series and (b) a factor allowing a filtering at the said fixed frequency and formed by the samples of the sine of the fixed frequency shifted by 45.degree.. These products are alternately stored in accumulators until after a certain time the presence of certain frequencies is deduced from the sum of the products in the accumulators by means of comparison.

Abstract: A ground station system for automatically monitoring a predetermined plurality of carrier frequencies for radio communication calls from aircraft which transmit and receive traffic over one of said carrier frequencies, wherein the aircraft transmits a calling code signal for a selected ground station, and each of the ground stations has a separate receiver for each of said carrier frequencies. Each receiver is connected to a decoding device which detects only complete and correct calling code signals for that particular ground station. In addition to each of the calling code signals having a first calling part for the pre-selected ground station, each calling code signal also may have a second or an information part indicating the direction sector of the aircraft with respect to the called ground station, the way of modulation or modulation scheme, e.g. A-M or S.S.B., and the company or party being called at that station.

Abstract: Detection device for detecting movements by means of a source of light and a photo-detector, which device is provided with: (1) a pulse generator for supplying the source of light with a proportionally very large amount of energy during a very small part of the time; and (2) with a comparator, synchronized with the pulse generator, for comparing a signal received from the photo-detector with the preceding signal during the said time and for delivering a signal to a counter in case a difference is ascertained. The device can be utilized in a manual sorting device comprising one or more sorting-cases. Movements of the upper surface of the stack in a pigeon-hole can be detected by means of reflection. The detection devices in the pigeon-holes are connected via multiplexers and demultiplexers to a central processing unit that has been provided.

Abstract: Omnidirectional antenna provided with a rotation-symmetrical reflector and a concentric radiator, to be mounted around a mast, which radiator has an uninterrupted annular exit edge. All the diametrical cross sections of the radiator along the axis of the antenna are uniform. The path followed by the radiation in the radiator beyond the part deflecting from the axis of the antenna, is turned up in the direction of the reflector.

Abstract: A system for generating a special calling signal to be transmitted from an aircraft to a ground station comprising two parts of repeated groups of 7-unit binary code signals, each of which parts or groups has a constant ratio of 1 and 0 value bits, but has a different ratio for each part or group. The first part or group comprises alternating signals of "idle time" with two successive signals representing the tens and units digits of the call number of one of a hundred different ground stations to be called. This alternate sequence of tens and units signals is repeated a sufficient number of times so as to avoid any error in the reception of a signal from this part and also to place the receiving ground station in phase and synchronism with the calling station in the aircraft. Then the second part or group of the whole calling signal is transmitted which second part comprises three successive separate message signals which are alternately repeated in succession every fifth signal interval.

Abstract: The invention relates to a method for the automatic recognition of characters, preferably of figures, which may be hand-written on an information carrier provided with an arrangement of demarcated rectangles- one for each character. These handwritten characters are projected on to a matrix, where a camera tube ensures the scanning of the matrix, and the information thus read is recorded in a store and subsequently handled by a processor.A device for carrying out this method comprises a character pattern manipulator connected to the store in the processor, the output of which manipulator is connected to a number of properties of signals derived from scanning the characters. This manipulator comprises means for copying or transferring the information stored in the processor to other storing matrices, rotating the information stored therein in successive 90.degree. turns, shifting and dividing the stored information, and erasing undesired information parts from the rectangles.

Abstract: Device for marking or writing a parallel bar code onto a document such as a postal article, comprising a number of parallel separately electromagnetically selected printing-styli and cooperating spring, crank, lever, and stop means for moving the end of each selected stylus toward and across or along the surface of the document to write or mark a bar thereon.

Abstract: System for transmitting a series of bits with an indefinite length by transmitting and receiving between two stations parts of the series in balanced blocks and maintaining automatic synchronization of said blocks by generation of two types of similar framing blocks recognizable by a special signal in a fixed place in each framing block. These framing blocks also include the code number of the channel then to be transmitted. One type of framing block is generated when a loss of phase is detected in said bits at one station, which one type of framing block is continuously transmitted to the other station whereupon receipt thereof causes the generation of the other type of framing block at the other station. This other type of framing block then is continuously transmitted back to said one station, until it is detected at said one station indicating that reframing or synchronization has occurred, so traffic or information blocks can be and are resent again from said one station.

Abstract: A method for indicating the free-line state of a subscriber's line connected to a terminal exchange in a binary data communication system comprising generating and transmitting to the exchange a special code word or byte of a plurality of a fixed number of "0" and "1" bits, such as alternate "0" and "1" bits. This special code word is sent after the closing signal at the end of the communication or traffic, which closing signal comprises a byte of only one "1" bit and nine "0" bits, and before the start-again-of-traffic signal, which start signal comprises a byte of only one "0" bit and nine "1" bits. The special free-line state code signal or byte not only indicates the line is free but also can, by the frequency of its alternate bits, indicate to the exchange terminal its modulation rate so that the subscriber can be automatically connected for the next traffic at this rate.