Abstract: A method and apparatus for transmitting a digital television signal using a single QAM (quadrature amplitude modulated) carrier which provides audio and video data packets at respective complex symbol data rate levels. One purpose of the invention is to provide a digital television signal which resembles the audio vs. video reception characteristics exhibited by conventional analog television (i.e. NTSC). way communication path.

Abstract: The invention relates to a device for recovering a symbol timing for the decoding of received signals formed by code-modulation symbols transmitted in an orthogonal frequency-division multiplexing mode (OFDM). The signals are formatted in symbol blocks of which each block presents redundant information. The invention comprises means for delaying the symbol blocks and for subtracting from a symbol block the delayed symbol block corresponding thereto. In this manner a difference signal e(t) is obtained which is used for controlling a loop formed by a local oscillator operating at the clock frequency, a frequency divider and a phase comparator.

Abstract: In a motion-compensated picture signal interpolation apparatus comprising switched memories (SMX,LM) for furnishing motion-compensated pixel values corresponding to at least two motion vectors (.+-.d, 0), the motion-compensated pixel values are processed by an ordered statistical filter (MED).

Abstract: A method and decoder for decoding a hierarchically coded digital video bitstream which can process a high resolution television picture in real time and which is made, up of a number of individual decoder modules, connected in parallel, which each have less real time processing power than is necessary, but which when combined, have at least the necessary processing power needed to process the bitstream in real time. The decoder includes a system controller which detects the hierarchical code indicating bits and slices and communicates this information to a slice parser which dynamically allocates the bitstream among the digital modules as needed on a per slice basis.

Abstract: Video encoder and decoder, provided with a motion compensator for motion-compensated video coding or decoding in which a picture is coded or decoded in blocks in alternately horizontal and vertical steps. The motion compensator is provided with addressing means (160) and controlled multiplexers (111-119) for refreshing a search area memory (101-109) at each step, in conformity with the direction of the step.

Abstract: An ATV receiver having a decoder which is designed to process a subset limited trellis pre-coded television signal. The decoder processes co-channel interference so as to produce at the filter output of a rejection filter, a residual interference spectrum which is as flat as possible. The filter exploits the fact that only the picture and the sound carriers need to be sufficiently attenuated and cancels NTSC co-channel interference with only a small degradation in performance when AWGN is also present.

Abstract: In a motion-compensated picture signal interpolation apparatus comprising a field memory (FM2) for delaying an input field sequence, a motion vector estimator (ME) for furnishing motion vectors, and a motion-compensated interpolator (MC) coupled to an input and an output of the field memory (FM2) for furnishing a sequence of motion-compensated output fields on the basis of the motion vectors, inputs of the motion vector estimator (ME) are coupled to the input and the output of the field memory (FM2) to estimate the motion vectors by means of the same single field memory (FM2) which is used for the motion-compensated interpolation. (FIG.

Abstract: An adaptive equalizer includes a digital linear filter having adjustable weighting factors and which is connected to a summator and a control unit so as to form two filter loops, one direct and the other recursive, the filter being shared in both loops. The control unit provides a weighting factor which establishes a selected relative proportioning of the data signals which traverse each loop, so that the equalizer is proportioned as to the degree to which it provides direct filtering and the degree to which it provides recursive filtering. Recursive filtering is employed to the maximum extent consistent with operating stability, the relative proportion of direct filtering being increased as necessary in order to maintain stability during equalization of any particular received data signal.

Abstract: In a digital transmission system comprising a transmitter (2) connected to a receiver (6) through a channel (4), this receiver comprises an equalizer (8) which includes an equalization filter (12) with output signals from which a sum weighted with weight factors is determined. The output signal of the equalizer is applied to a detector. According to the inventive idea a correction signal for correcting the coefficients w of the equalizer is derived from w.sub.k =w.sub.k-1 +Ma.sub.k e.sub.k, where a.sub.k is the vector of a plurality of successive detected symbols, and e.sub.k is a difference between the current input signal of the detector and a reconstructed ideal input signal of the detector.

Abstract: A picture display apparatus adapted to pictures having an aspect ratio 16/9, permitting the simultaneous control of the line length and the vertical spacing of the lines. For the reception of pictures having an aspect ratio 4/3, the two control circuits are coupled in such a manner that the length of the lines of the displayed picture is decreased (2, 20) when the vertical spacing of the lines is normal or that the length of the lines of the displayed picture is normal when the vertical spacing between the lines is increased (3, 6). In addition, the control circuits are a continuously variable type, and access of the user to the control circuits is effected by remote control.

Abstract: A system comprising a user interface which can access downloaded electronic programs (e.g. pay per view movies) and information records related to said programs, which can be continually updated and provided over cable or satellite transmission paths or other "fast data" paths, and which can automatically correlate the program information with the preferences of the user, to create and display at least one personalized information database based upon the results of the correlation.

Abstract: In a video processing system having an intra-field processing mode which allows a better luminance-chrominance separation, and an inter-field processing mode which allows a better performance in the presence of motion in the color signals, wherein a motion-dependent choice is made between these modes, chrominance-difference signals (Ud, Vd) are derived from chrominance signals (U, V), and a first linear combination of the chrominance-difference signals (Ud', Vd) is derived when the V chrominance-difference signal (Vd) exceeds the U chrominance-difference signal (Ud'), and a second linear combination of the chrominance-difference signals (Ud', Vd) is derived in the opposite case, to obtain a motion signal (M) for the motion-dependent choice.

Abstract: Device for recursive processing of a video signal, comprising a plurality of n branches, for recursive parallel processing of a video signal, comprising at least a MEMORY BANK structure (1, 2, 3, 4) which includes: a demultiplexor for demultiplexing the video signal into a plurality of n temporally adjacent sections T1 . . . Tn having a period of T; a decompressor for temporal decompression of each section T1 . . .

Abstract: A system comprising a user interface which can access downloaded electronic shopping information, which can be continually updated and provided either "over the air", over cable or satellite transmission paths or other "fast data" paths, and automatically correlate this information with the preferences of the user, to create and display at least one personalized shopping information database based upon the results of the correlation.

Abstract: In an arrangement for converting an original picture signal representing a sequence of frames, each of which is composed of two interlaced fields, into a converted picture signal which has a double field frequency with respect to the original picture signal, is for doubling the field frequency, for the purpose of noise reduction, motion compensation and line flicker reduction, a memory arrangement (1, 2) provided for doubling the field frequency, which memory arrangement precedes a motion compensation arrangement (5) whose output signal is applied to a noise reduction arrangement (6), and a line flicker reduction arrangement (7) is provided which receives the output signals from the noise reduction arrangement (6) and the motion compensation arrangement (5), while the converted picture signal is obtained from the output signal of the noise reduction arrangement (6), the line flicker reduction arrangement (7) or the motion compensation arrangement (5), dependent on the position with respect to time of a field

Abstract: The invention relates to the synchronization of a local clock (VCO) with a first clock frequency (Fo) equal to that of time-spaced digital data bursts read from a record carrier which also carries a continuous digital signal (H) of a second clock frequency (F). In accordance with the invention, locking to the desired frequency is assured by a frequency comparator (FD) which detects the frequency shift between the signal (S) of the local clock (VCO) and the signal of the second clock frequency (F). The device also comprises a phase-locked loop (PD) which provides phase locking once the synchronization has locked to the correct frequency.

Abstract: A rejection filter for use at an ATV receiver which is designed to process co-channel interference so as to produce at the filter output of the filter, a residual interference spectrum which is as flat as possible. The filter exploits the fact that only the picture and the sound carriers need to be sufficiently attenuated and cancels NTSC co-channel interference with only a small degradation in performance when AWGN is also present.

Abstract: Receiver (5) for digital signals which comprises a differential decoding circuit deinterleaving and convolution decoding circuit for received digital signals. The differential decoding circuit restores each received symbol to the original phase it had on transmission. This permits the calculation of optimum metrics(M.sub.k.sup.a,M.sub.k.sup.b)which are used by convolution decoding circuit to provide optimum decoding of received symbols.

Abstract: Arrangements for recording and reproducing datareduced videoinformation are described. The recording arrangement comprises a datareduction unit (3) and a formatting unit (4). The formatting unit (4) generates packets (P.sub.i) each having a first, second and third packet portion (PP.sub.1, PP.sub.2 and PP.sub.3). The first packet portion comprises a sync word (SW) and an identification word. The second packet portion comprises datareduced videoinformation of a first and a second datablock (MB.sub.0, MB.sub.1). A datablock comprises DC coefficients (DC.sub.i) and most significant and least significant AC coefficients (MAC.sub.i, LAC.sub.i). The videoinformation comprised in the first and the second datablock are stored in the second packet portion (PP.sub.2), such that the DC coefficients of the first datablock (DC.sub.0) are stored first, the plurality of most significant AC coefficients (MAC.sub.0) of the first datablock are stored next, the DC coefficients of the second datablock (DC.sub.

Abstract: To be able to transmit television pictures in a digital form through a medium having a limited bandwidth, the pictures are subjected to picture transform and to variable-length coding. The picture to be transmitted is converted in this manner into a bit stream comprising code words of variable length. This bit stream is converted into a channel bit stream which is less sensitive to transmission errors. To this end the most significant code words (representing the average luminance and the coarse picture details) of sub-pictures of 8*8 pixels are accommodated at fixed bit positions of the channel bit stream. These code words can be retrieved by simple count-down of the bit positions. The other code words are distributed over the other bit positions. The decoder is relatively simple because the length of each block comprising significant code words is also transmitted. This length is preferably adapted to the extent of picture detail in the sub-picture.