Abstract: A method and apparatus for introducing a pan and scan feature to a multiple-signal high definition television (HDTV) system, so that a compatible signal received by a standard TV receiver may be a panned version of a wide aspect ratio HDTV signal, and so that high quality recombination of the compatible and augmenting signals by an HDTV receiver is possible. A pan and scan data word representing the relative movement of the compatible portion of the HDTV signal is inserted during the vertical blanking period of each frame of the HDTV signal, for causing panning synchronization between an HDTV transmitter and an HDTV receiver. The pan and scan data word corresponds to the beginning read address of a fixed coefficient memory containing video attenuation coefficients, which determine the degree of signal attenuation, to be applied at each pixel location along an HDTV scan line.

Abstract: In a television transmission system each picture is subjected to a number of picture transforms for limiting the bit rate. In each picture transform the picture is partitioned into sub-pictures of a given size. The sub-picture size is different for the different picture transforms. Each sub-picture is converted into a limited number of predetermined coefficients by use of a sub-picture transform. This number is related to the sub-picture size. With the matrix of coefficients thus obtained for each picture an approximation of the original picture is made by use of an inverse transform and this approximation is subjected to one of the said forward transforms. The matrix of coefficients now obtained is subtracted from this matrix of coefficients which is obtained by subjecting the original picture to the same forward transform.

Abstract: In a pay television system, a program signal is transmitted scrambled to prevent its unauthorized reception, the scrambled signal being accompanied by authorization codes, one for each authorized subscriber, a subscription key and a pay-per-view key. At a receiver, if the appropriate authorization code is received, the receiver functions in the subscription mode in which mode the subscription key provides for the descrambling of the program signal. If the appropriate authorization code is not received, indicating that the subscriber is not pre-authorized to receive the program in an intelligible manner, the receiver is set to function in a pay-per-view mode in which mode, on request, the pay-per-view key provides for the descrambling of the program signal. If there is a delay receiving the appropriate authorization code, the receiver can be set into the pay-per-view mode for at least the period of the delay, so that the scrambled signal is immediately rendered intelligible.

Abstract: A direct coupled switched mode power supply designed for the AC to DC power conversion in for example CAT TV systems and equipment. The power supply is constructed to have a conversion efficiency of between 85 and 90%. It achieves these efficiencies by utilizing a pulse transformer having a duty cycle of greater than 50% in conjunction with an output control circuit, a driver circuit and an output filter circuit all designed to work together to effect increased efficiency.

Abstract: A simple and reliable interpolation filter can be provided by a median filter 9 to which signals of the pixels x.sub.1, x.sub.2 and x.sub.3 are applied and which can supply incorrect output values at high spatial frequencies perpendicular to a connection line of pixels x.sub.3 and x.sub.4 located diametrically with respect to a pixel (.) to be interpolated, in conjunction with an averaging circuit 25 to which signals of the pixels x.sub.3 and x.sub.4 are applied and which will not be disturbed at the said frequencies, but will cause disturbances at high spatial frequencies in the direction of this connection line x.sub.3 -x.sub.4, at which last-mentioned frequencies the median filter 9 will function correctly again.

Abstract: Data are frequently transmitted via a dual bus line by means of differential signals which are evaluated by a differential amplifier, particularly for reasons of protection against interference. However, such a differential amplifier only has a limited input voltage range, or a dead voltage range of the input signals within which it is not capable of operating. To prevent the voltages on both bus lines from getting into this dead voltage range, either due to a common-mode interference signal on the bus lines or due to a voltage dip in the feed voltage of the differential amplifier, the two bus lines are connected in accordance with the invention to an adjusting circuit which changes the voltages of both bus lines by the same amount in the direction out of the dead voltage range. This prevents unspecified conditions of the differential amplifier without significantly influencing the differential signal on the two bus lines. The application for an integrated memory is described.

Abstract: The invention relates to a circuit arrangement for a video recorder, which derives from a video signal the video programming data (VPS data) and generates a test signal that shows whether a television signal is present, whether interference pulses are present, whether VPS data are being transmitted and whether the transmission of the VPS data is free from errors.

Abstract: A matrix display system includes an active matrix display device (10), for example a liquid crystal device, having a column and row array of picture elements (12) defined by opposing electrodes (16,17) with associated switching elements (11), such as thin film transistors, which are selectively operable by switching signals supplied via row conductors (14) to apply data signals supplied via column conductors (15) to the picture elements. The picture elements (12) are arranged in groups of at least two with the picture elements of each group being addressed via one row conductor (14) and one column conductor (15) and their associated switching elements (11) being operable at respective different levels of the switching signal for selective control. In this way, the number of address conductors (14,15) required can be reduced, allowing for example higher picture element densities. The picture elements of each group may be from the same row or adjacent rows.

Abstract: Image processing system for the acquisition and processing of video signals corresponding to a plurality of images. The system provides space-time filtration of similar behavior in the images in both the space direction and the time direction.

Abstract: Picture display device having a display tube (3) and a deflection unit (9) comprising a field deflection coil and a line deflection coil (11). To comply with a predetermined interference radiation standard, the picture display device comprises a first set of (horizontal) interference suppression coils 18, 19 arranged symmetrically relative to the plane of symmetry of the line deflection coil and a second set of (vertical) interference suppression coils 18a, 19a arranged at right angles to the plane of symmetry of the line deflection coil, which coils are oriented in such manner and in operation are energizable in such manner that, measured at a predetermined distance from the picture display device, at least the strength of the local magnetic dipole field is below a desired standard. Each coil of the second set preferably comprises at least two sub-coils arranged parallel to each other at a given distance in order to reduce the energy content of the coil system.

Abstract: Picture display device having a display tube and a deflection unit comprising a field deflection coil and a line deflection coil. To comply with a predetermined interference radiation standard, the picture display device is provided with one interference suppression coil or system of interference suppression coils is orientated and can be energized in such a manner that, measured at a predetermined distance from the picture display device, the strength of the dipole component is below a desired standard.

Abstract: A high definition television signal with a sequential scan with the standard number of lines per frame and double the frame frequency is processed to generate a single MAC line having a duration substantially equal to that of four sequential lines of standard duration. Each MAC line has two luminance components having different compression ratios. For the remaining two lines, compressed line difference signals are transmitted, thereby allowing reconstruction of all luminance lines at the receiver. Each MAC line further has a U chrominance component and a V chrominance component, alternatively compressed 1:4 and 1:2. The remaining parts of each MAC line are taken up by data signals and audio as well as the necessary clamping. The luminance and chrominance signals are prefiltered to prevent artifacts. The filtering is geared to the visual characteristics of the human visual system, i.e.

Abstract: A method and apparatus for coding a signal for transmission in order to achieve improved reduction in the bit rate. A signal is a transform coded in order to form a sequence of zero coefficients and non-zero coefficients, and run lengths of zero coefficients together with preceding or subsequent non-zero coefficients are grouped as events and coded.

Abstract: A television signal for a television transmission system conveys a motion information signal in addition to the vision signal. At the transmission side each field of a picture is subdivided into a plurality of regions and up to a given number of the most dominant motion vectors appropriate to a region are generated. These motion vectors are transmitted as the motion information signal and in a receiver are separated from the television signal in a decoder (12). The spatially offset pixels are identified in a first spatial offset circuit (14) from a vision signal delayed by a picture memory (16) and compared in a picture information comparison circuit (17) with pixels in the corresponding field of the current picture to identify the motion vector indicating the pixel of corresponding magnitude.

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 of erroneous and correct picture elements, the erroneous picture elements being entirely enclosed by the correct picture elements. Before restoring the erroneous picture elements, a correction function is determined, starting from the correct picture elements of the reference sub-picture, and by means of this correction function a correction value can be determined for each correct picture element in the reference sub-picture such that the difference picture elements obtained by subtracting the associated correction value from each correct picture element represent a signal whose mean value is zero. A known method of restoring erroneous picture elements can now be used for these difference picture elements.

Abstract: A receiver for a PSK-signal includes a demodulator for obtaining a demodulated data signal which after regeneration is applied to a remodulator for PKS-remodulation of the received PSK-signal to produce thereby a carrier component that is applied as an input signal to a phase-locked loop in which a local carrier generator is included. The reliability of the carrier recovery for low SNR-values can be improved by the generation of delayed and advanced versions of the regenerated data signal, and by providing the receiver in addition with a clock tracking unit, responsive to the received PSK-signal, the local carrier and the delayed and advanced data signal versions, for generating a control signal for a local clock generator connected to the regeneration means.

Abstract: A water-proof outdoor tap distributor of cable TV network system electrical signals wherein the electro-pin of a tap connector is designed with two different size sheets, a shorter one being assembled in the middle of a longer one and the longer one being stretched up to the end side as a transmission point; the exposed electro-pin of the connector being covered by a super design glue and every connector being also covered with a second glue to prevent water leaks into the inside of the PCB and internal cavity.

Abstract: In known color-under video recorders intertrack chrominance cross talk is eliminated by comb-filtering of the back-converted chrominance signal. However, if the delay circuit needed in the comb filter is a CCD delay line this will give rise to problems both in respect of production engineering and circuit design. These problems are mitigated by the novel comb filter. Comb filtering is applied to the down-converted chrominance signal. The signal path in which the signal is delayed includes a clocked CCD delay line and a phase correction circuit having a linear frequency response and whose dimensioning is such that the overall delay of the chrominance signal corresponds to the signal periodicity imposed by the signal standard and that the phase shift which occurs in the down-converted signal as a result of the recording standard in conjunction with the signal standard is eliminated.

Abstract: A charge-coupled memory of the SPS type, in which the input of the series input register is coupled so as to be switchable to an n-bit shift register. The data can thus be read in directly or with a certain delay via the shift register. If an uninterrupted flow of bits is supplied, for example video information, a pause, during which no bits appear at the input of the input register, can be obtained by switching on the shift register in the supply of information to the input register, without information being lost. This pause can be utilized to transport information already read in to the parallel section. As a result, a matrix organization can be given to the memory, in which event the dissipation is lower, the transfer losses are smaller and at the same time a gain in surface area is obtained.

Abstract: A receiver comprising a multi-path detector which comprises a frequency noise peak detector, an AM-detector and a weighting circuit. When noise peaks and amplitude modulations occur in an antenna input signal selected by a diversity switch on account of a control signal of the weighting circuit one of a number of antennas is switched to. This switching is audible to an annoying degree. By inserting a threshold arrangement (31, 32) in the detector, by means of a low-pass filter and a rectifier circuit, an instantaneous threshold voltage is generated varying with the frequency swing of the modulating signal. With a large swing, corresponding with a large amplitude of the modulating signal, switching is audible to a less annoying degree. On the other hand, at moments when the modulating signal has a small amplitude, switching may take place more frequently and is less audible because of the small amplitude of the modulating signal.