Abstract: A system for transmitting sequences of digital samples encoded by variable-length binary words is formed on the one hand by a transmitter device comprising a statistic encoding circuit for encoding in said variable-length words words of a fixed length appearing at its input in the shape of sample sequences, a synchronizing circuit for forming synchronizing words which define the position of the variable-length words in the sequences and a multiplexer circuit for combining, in view of their transmission, the synchronizing words with the variable-length words, and, on the other hand, a receiver device comprising a demultiplexer circuit for applying from one of its two outputs the variable-length words received to a statistic decoding circuit for recovering the fixed-length words and for applying from the other output the synchronizing word to a processing circuit for restituting, in the event of a transmission error, the position of the samples in the sequence.

Abstract: A device for reproducing digitally presented video pictures includes a restoration circuit for restoring erroneous picture elements. To this end a reference sub-picture is composed from the erroneous picture elements and non-erroneous picture elements, the erroneous picture elements being completely enclosed by the non-erroneous picture elements. The erroneous picture elements are subsequently replaced by zero picture elements. Each picture element is then considered as a sum of weighted versions of picture elements which form part of a prediction field. The set of prediction coefficients associated with this prediction field is obtained by minimizing a prediction coefficient function. This operation is performed for different prediction fields and the restoration process is continued in known manner, this continuation being based on the prediction field yielding the smallest value for the prediction coefficient function.

Abstract: In a flat cathode ray tube display apparatus a line scanning, low energy, electron beam (18) is directed substantially parallel to a faceplate (12) carrying a phosphor screen (14) in a space between a deflection electrode array (22) and an input side of an electron multiplier (16) adjacent the screen where it is deflected by the electrode array (22) in field scan manner towards the screen. The deflector electrodes (23) in the array correspond in number to the conventional raster lines to be displayed and are switched successively between two voltage levels to step the line scanning beam. The electrodes' voltage switching drive circuit (52) may be carried on a substrate adjacent the electrodes thereby reducing the number of leadthroughs in the tube's envelope (15). For color display the screen comprises a pattern of different color phosphor elements and a color selection electrode arrangement (38) is situated at the output side of the multiplier (16).

Abstract: The horizontal definition of an interlaced television signal sampled in anti-phase from picture to picture can be enhanced by using a selection circuit with which a signal sample located horizontally between two successive signal samples from the current field is obtained from three horizontally successive signal samples of two successive pictures, which signal sample can be added between these signal samples from the current field.

Abstract: A method and apparatus for correcting errors in the digital data of a television signal, wherein the digital signals are Golay codes having 23 bits constituted by two parts: a message and a redundance. If there are between zero and three errors to be corrected, there are 2048 possible cases, whose examination one by one would be too time-consuming and/or too expensive in a memory. However, if there are two errors in one of the parts, there cannot be more than one error in the other part. Therefore, in a first case, one of the parts does not comprise errors and serves to recreate the other part (1-8) completely. In the other case, one of the parts comprises only one error: there is started from this part; the different bits susceptible to being affected by the single error thereof are modified in turn (9,12) and there is each tiem verified (10,13,15) whether the other part could correspond to the modified part. The total number of tests is thus strongly limited.

Abstract: A cathode-ray tube and deflection system suitable for a cathode-ray tube.A cathode-ray tube having a deflection system, comprising two switched line deflection coils, a coil being arranged between the deflection coils, and a line deflection system suitable for a cathode-ray tube. The coil reduces the occurrence of "ringing" on the picture screen without necessitating a modification in the design of the deflection system or the enivonment of the deflection system.

Abstract: From a television signal, a data packet transmitted within each line in time multiplex with the picture information is separated by means of a time gate, while in addition to each data packet. a version delayed in time is formed, all the data packets are subjected to a multilevel coding and the information associated with a line and present in multiple are recorded relatively offset in time on different oblique tracks of a record carrier.

Abstract: The invention relates to an optical relay which includes a target plate of an electrically insulating material and allowing the light to pass in a manner dependent on the electric field parallel to the direction of propagation of this light, means for scanning a first surface of this target plate by means of an electronic beam (34) controlled by a wehnelt electrode (34), an anode (38), an optically transparent plate (38) which is electrically conductive and which receives the visual information electric signal from an amplifier which supplies a video signal. The optical relay operates with a further amplifier (52) which applies a small overmodulation supplied by the video signal to the wehnelt electrode in order to enhance the readability. The overmodulation may be automatically controlled by means of a picture integrator.

Abstract: A component television signal is transmitted as a sequence of television frames with each frame having a plurality of television lines substantially all of which have first and second time multiplexed portions. The first portion (DB) forms the data burst and conveys sound/data information in digital form at a given bit rate while the second portion of each line outside the vertical blanking intervals (VBI) conveys vision information (U/V, Y). The second portion of at least some of the lines in the verical blanking intervals (VBI) convey additional information in digital form at a higher bit rate than the given bit rate and which may be twice the given bit rate. This additional information can be the digital channel information for a digitally assisted television signal.

Abstract: In a transmission system authorization codes are transmitted to authorize subscribers to receive scrambled signals in an intelligible manner, such a system being a television transmission system. If each subscriber were assigned a unique authorization code an extremely long period of time would be required to transmit these codes for a national broadcast system. With the present arrangement, the authorizing code includes a multi-bit binary code word (18,20) which is unique to a group of subscribers, this code word being followed by a train of binary pulses (19',19";21', 21",) the number of pulses in the train being not less than the number of subscribers in the group. Each subscriber is allocated a unique pulse position in the pulse train (19',19";21',21",) at which position the state of the pulse either authorizes or inhibits the subscriber from receiving the scrambled signal intelligibly.

Abstract: A pyramidal coding circuit comprises a decimation circuit (14.1) which receives the picture consisting of M.times.N pixels to be transmitted and converts it into K+1 auxiliary pictures B.sub.k, the numbers of horizontal and vertical pixels of B.sub.k being smaller by respective factors A.sub.H and A.sub.V than those of the auxiliary picture B.sub.k-1 (k=0, 1, 2, . . . K) preceding in ordinal number. Each auxiliary picture B.sub.k is expanded in an expansion channel 14.4(.) to an expanded auxiliary picture B'.sub.k having the same number of horizontal and vertical pixels as the auxiliary picture B.sub.k-1. In a difference picture former 14.7 (.) the auxiliary picture B.sub.k-1 and the expanded auxiliary picture B'.sub.k having the same number of horizontal and vertical pixels as B.sub.k-1 are subtracted from each other for generating a difference picture D.sub.k-1. The expansion channel has not only a two-dimensional interpolating low-pass filtering function 14.5(.) but also a picture prediction function 14.

Abstract: A digital circuit which receives a serial input signal and which suppresses fast signal variations. The digital circuit includes an integrator circuit (1) which generates a multi-bit signal by integration of the serial input signal. The output signal of the integrator circuit is applied to an evaluation circuit (2) which generates a serial output signal which assumes a first state when the multi-bit signal exceeds a first threshold value and a second state when the multi-bit signal is below a second threshold value.

Abstract: A device for decoding a transmitted sequence of duobinary encoded signals, which provides as an output a sequence of binary signals which most probably matches the transmitted sequence of duobinary encoded signals, estimated as a function of the duobinary signals actually received by the device.

Abstract: A switching device is realized by means of two amplifier paths which are controllable by means of transistors. The collectors of output transistors (T1, T1B) are connected together, without an impedance matching circuit for each path, to a common point (10) being connected to an impedance matching circuit (L5, R7) which is common for the two paths. This switching device is particularly used for selecting signal paths between 1 and 2 GHz in systems for receiving television signals by satellite.

Abstract: An adaptive comb filter employs vertical and horizontal edge detectors to selectively activate a vertical high-pass filter and a horizontal band-pass filter during the occurrence of vertical and horizontal edges in a received television signal, for use in the chrominance/luminance separation process. Artifacts such as "hanging dots" and "crawling dots", inherent in prior art comb filter circuits during the occurrence of vertical and horizontal edges in the composite television signal, are greatly reduced in the process.

Abstract: A pulse train divider circuit includes a first flip-flop (1) whose Q output is connected to the D input of a second flip-flop (2) whose Q output is connected to the D input of the first flip-flop (1). A pulse train to be divided is applied via an input (3) directly to the clock input C of the first flip-flop (1) and via a circuit (4) which delays the pulse train applied to the clock input C of the flip-flop (2) to provide a given phase relationship between the pulse trains at the two clock inputs. The circuit divides-by-two, and the resulting divided pulse trains available at the various outputs have phase relationships depending on the phase relationship of the applied pulse trains at the clock inputs.

Abstract: The invention relates to a phase comparison circuit for determining the phase deviation between an input signal and a reference signal. The input signal is integrated during two consecutive defined integration intervals which are derived from the reference signal. The integral values assigned to the integration intervals are weighted and the difference is formed. The output signal of the phase comparison circuit is derived from the result of forming this difference.

Abstract: A circuit for deriving a synchronizing signal contained in an incoming video signal, having a pulse generator generating the synchronizing signal when the incoming signal reaches a threshold value. This treshold value corresponds to a level located between the peak and reference levels of the incoming signal and is determined with the aid of a keyed integrator, which integrates the video signal during a period of time which at least partly coincides with the occurrence of an incoming line synchronizing pulse and during a period of time after this occurrence, but before the end of the line blanking interval. In the synchronized state of the line synchronizing circuit, the required keying pulses are generated by this line synchronizing circuit; in the non-synchronized state the keying pulses are derived from the delayed output signal of the pulse generator. (FIG. 2).

Abstract: A multiplex circuit includes a cascade connection of flip-flop elements for producing a high data-rate multiplex signal. In order to avoid disturbances caused by parallel loading of the flip-flop circuits, the slave-section of the flip-flop generating the multiplex signal is not parallel loaded, which results in a continuous output signal.