Abstract: A digital data modulator includes a source of a plurality of digital data signals having a common data bit period. A plurality of encoders each encode a corresponding one of the plurality of digital data signals using a variable pulse width code having edges occurring in respective non-overlapping intervals within the data bit period. A plurality of pulse signal generators each generate respective pulses representing the edges of the corresponding one of the encoded plurality of digital data signals. A carrier signal generator generates a carrier signal having carrier pulses corresponding to the respective pulses.

Abstract: A control interface for the bit rate of digital data to be recorded as well as a control interface for the bit rate of digital data emanating from a reading device, particularly when the digital data constitutes a high bit rate uninterrupted data stream such as a video data stream in the MPEG II format. Each control interface comprises a memory circuit for storing the data to be recorded or to be read and a device for storing the data to be recorded or read in the memory circuit so as to fill the memory circuit to a predetermined level. The storing device includes a gauge for generating an information item giving the fill level of the memory.

Abstract: A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information and a pilot component includes an input analog-to-digital converter (19) for producing a datastream which is oversampled at twice the received symbol rate, and a digital demodulator (22; FIG. 3) with a data reduction network (330, 332) in a phase control loop. A segment sync detector (24; FIG. 4, 5) uses an abbreviated correlation reference pattern to recover a twice symbol rate sampling clock for the digital converter (19). A DC offset associated with the pilot component is removed (26; FIG. 6) from the demodulated signal before it is applied to an NTSC interference detection network (30; FIG. 7). The interference detection network includes a comb filter network (710, 718) responsive to a twice symbol rate sampled data datastream, and exhibits a sample delay dimensioned to avoid aliasing in the combed frequency spectrum (FIG.

Abstract: The invention relates to a process for coding digital data from a sequence of video images carrying out a coding of the difference in luminance (7) between an image segment to be coded and a corresponding segment of an image predicted from a so-called reference image, characterized in that the prediction is made as a function of a luminance compensation (12) of values of luminance of the reference image. The field is that of the compression of digital video data.

Abstract: A sample rate conversion system converts data of a first sample rate to data of a different second sample rate. The system involves an interpolator, operating at the first sample rate and includes a first interpolation network and a delay network. The first interpolation network interpolates the first sample rate data to provide upsampled interpolated data samples according to a first sample spacing. The delay network interpolates the upsampled interpolated data to provide delayed upsampled interpolated data samples, according to a second sample spacing of higher resolution than the first sample spacing, and preceding and succeeding an original sample position. The system also includes a digital filter operating at the second sample rate for filtering the higher resolution data samples to provide the second sample rate data.

Abstract: In noise measurement for video sequences it is difficult to distinguish between picture content and noise. In order to improve the measurement reliability the results of two different noise level computing methods are combined. One computation relies on the analysis of displaced field or frame differences, the other is based on the values of the field or frame differences over static picture areas.

Abstract: In an OFDM system, the so-called self-noise component, which represents that noise component of the respective carrier which is caused by the carrier itself and is mapped onto itself, can be estimated and corrected by shifting all the carriers back in the receiver by multiplication by a factor which is determined by averaging. The so-called external-noise component, which is caused by adjacent carrier interference from the so-called leakage effect of the Fast Fourier transform (FFT2) used in the receiver for demodulation cannot be corrected using this method. In addition to the demodulation FFT, a further FFT (FFT1) is used in the receiver to estimate the self-noise component (&psgr;e). The estimated self-noise component is used to reproduce the orthogonality between the carriers by correction before the demodulation FFT, to thereby prevent crosstalk. The additional FFT (FFT1) may have a shorter length than the demodulation FFT (FFT2), so that the additional complexity is negligible.

Abstract: A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information and a pilot component includes a carrier recovery network (22; FIG. 3) that produces a demodulated baseband signal. The carrier recovery network additionally responds to a locally generated control signal (Ph. Offset; 360) representing an unwanted phase offset of the pilot signal due to multipath distortion, for example. The control signal is used to compensate for the pilot phase offset before the demodulated signal is equalized. The control signal is produced by correlating received sync values with both a reference sync value (362) and a Hilbert transform of the reference sync value (363). The output of the carrier recovery network signal is phase compensated twice.

Abstract: Video signal compression apparatus generates residues representing pixel value differences between predicted and real pixel values of a current frame of a video signal. Noise reduction circuitry, in the form of nonlinear processing functions, attenuates lower amplitude residues greater than higher amplitude residues and is responsive to a noise estimate. The processed residues are transformed to provide a compressed video data output. The nonlinear processing functions attenuate noise and reduce image distortion.

Abstract: In the radio transmission method according to the invention, which operates with a mixed frequency and time division multiplex method FDMA/TDMA, in which a relatively broad frequency band is divided according to the FDMA method into a plurality of carrier frequency ranges, namely the so-called main channels, and a plurality of time slots, namely the so-called sub-channels, distributed in a frame structure, are formed on each carrier frequency level according to the TDMA method, a grouping, that is to say a so-called cluster, of subscriber stations is assigned a limited number of main channels. A main channel signal is divided into one or more sub-channel signals which are associated with a cluster and which are transmitted using the TDMA method.

Abstract: A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information includes an input analog-to-digital converter (19) for producing a digital datastream. A symbol timing recovery and segment sync recovery network (24; FIG. 3, 4) develops a properly timed sampling clock for the digital converter (19). The symbol timing recovery network (310) responds to an output from the segment sync recovery network (328), which in turn responds to an equalized signal from an adaptive channel equalizer (34). A controlled oscillator (336) generates the sampling clock for the digital converter. A control network (340, 344, 348; FIG. 3) shifts the frequency range of the oscillator to maintain desired linear operation to enhance symbol timing acquisition.

Abstract: In a method for fractal coding of signals, in which a domain block d is investigated for a range block r to be transmitted from an original signal, so that, after using the calculation rule r*=v·d+b, an approximated range block r* is generated, v·d being a linear function and b being an offset vector, the offset vector b in general has different components b=(b1, b2, . . . , bn) the offset vector b preferably being composed of weighted orthogonal basic functions of an orthogonal transformation.

Abstract: A carrier recovery process for a received signal comprises estimating the signal carrier frequency, and estimating the signal phase after frequency estimating. During frequency estimating, signal equalizing is performed, during which an equalizer comprising a direct adaptive filter and a recursive adaptive filter adapts only the coefficients of the recursive adaptive filter. During phase estimating, the equalizer adapts only the coefficients of the recursive adaptive filter for a predetermined time.

Abstract: A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information and a pilot component includes an input analog-to-digital converter (19) for producing a datastream which is oversampled at twice the received symbol rate, and a digital demodulator (22; FIG. 3) with a data reduction network (330, 332) in a phase control loop. A segment sync detector (24; FIGS. 4, 5) uses an abbreviated correlation reference pattern to recover a twice symbol rate sampling clock for the digital converter (19). A DC offset associated with the pilot component is removed (26; FIG. 6) from the demodulated signal before it is applied to an NTSC interference detection network (30; FIG. 7). The interference detection network includes a comb filter network (710, 718) responsive to a twice symbol rate sampled data datastream, and exhibits a sample delay dimensioned to avoid aliasing in the combed frequency spectrum (FIG.

Abstract: A memory efficient image processor receives DPCM prediction error values from decompressed MPEG coded digital video signals in the form of pixel blocks containing luminance and chrominance data in a 4:2:2 or 4:2:0 format and recompresses the pixel blocks to a predetermined resolution. Luminance and chrominance data are processed with different compression laws during recompression. Luminance data are recompressed to an average of six bits per pixel, and only a reference pixel and one other pixel are processed separately from all other luminance pixels in a block. Chrominance data are recompressed to an average of four bits per pixel. Each pixel block is stored with overhead information facilitating efficient and accurate reconstruction.

Abstract: A Conversion system merges and converts data in a plurality of different data formats from a plurality of different sources, to a selected output data format for transmission on a selected transmission channel. A method for digital data format conversion involves de-packetizing an input packetized datastream. A timing recovery parameter is formed in response to a desired output data format. The depacketized data is re-packetized in response to the desired output data format and the timing recovery parameter is incorporated in the re-packetized data. The re-packetized data is multiplexed in response to the selected format and provided to an output channel.

Abstract: A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information and a pilot component includes an input analog-to-digital converter (19) for producing a datastream which is oversampled at twice the received symbol rate, and a digital demodulator (22; FIG. 3) with a data reduction network (330, 332) in a phase control loop. A segment sync detector (24; FIGS. 4, 5) uses an abbreviated correlation reference pattern to recover a twice symbol rate sampling clock for the digital converter (19). A DC offset associated with the pilot component is removed (26; FIG. 6) from the demodulated signal before it is applied to an NTSC interference detection network (30; FIG. 7). The interference detection network includes a comb filter network (710, 718) responsive to a twice symbol rate sampled data datastream, and exhibits a sample delay dimensioned to avoid aliasing in the combed frequency spectrum (FIG.

Abstract: The device is connected to a memory (7) by an address bus and a data bus. It is characterized in that, on a clock output, it delivers a clock signal (clki_b) to be sent to the clock input of the memory (6), in that the clock signal. (clki) utilized for buffering the addresses and the data to be sent to the memory is the same, with the possible exception of having undergone signal inversion, as the one (clki_b) delivered on the clock output, and in that the same signal (clki_b) is utilized by the buffer (r1) receiving the data from the memory to buffer the data sent by the dynamic memory on the data bus.

Abstract: Video processing image manipulation and trick play modes provide seamless normal play and trick play functioning. Specifically, a system processes video data including encoded digital packetized data representative of a sequence of individual images and ancillary data identifying characteristics of the individual images. The system involves a pre-processor for parsing the ancillary data to determine characteristics of the individual images prior to storing the encoded digital packetized data. The system also includes a multiplexer for filtering the encoded digital packetized data based on the determined characteristics to identify particular images of the image sequence for storage in a memory and for excluding other images of the sequence from storage.

Abstract: A digital VSB modulator includes a modulator to which an ongoing sampled data stream of 1-sample-per-symbol successive PCM symbol signal samples are applied as a modulating signal. A sampled carrier stream, occurring at the rate of the signal samples, is applied as a carrier input to the modulator. The carrier stream is composed of, for example, a repeated 4-sample-sequence of 1, −1, −1, 1 sample values. The output of the modulator is applied to a bifurcated multiplexed N-tap root Nyquist FIR filter, which produces a VSB bifurcated complex output signal having a DC-centered real (±R) sampled data output stream of 1-sample-per-symbol sample values and a DC-centered imaginary (±I) sampled data output stream of 1-sample-per-symbol sample values.