Abstract: Apparatus useful in electronics for the tape recording of a video signal, which is a baseband signal of a prescribed bandwidth extending up to a prescribed maximum frequency, processes the video signal to generate a folded-spectrum video signal. The video signal is digitized and supplied to a digital band-splitting filter with a cross-over frequency at one-half said prescribed maximum frequency, for separating the digitized video signal into samples of a lower-frequency-band component and into samples of a higher-frequency-band component. A balanced modulator is connected for modulating a folding carrier wave of the prescribed maximum frequency, which modulation is done in accordance with the higher-frequency-band component to generate a balanced modulation signal; and the balanced modulation signal is linearly combined with the lower-frequency-band component to generate the folded-spectrum video signal.

Abstract: Television images to be digitally recorded are divided into blocks and the discrete cosine transform DCT of each block is taken. The DC coefficient of each DCT block is scalar-quantized, and its AC coefficients are classified-vector-quantized (CVQ). The square of the value that part or all the AC coefficients among horizontal AC coefficients including a first AC coefficient and vertical AC coefficients including a second AC coefficient, according to the zigzag scanning sequence of DCT block, are subtracted from a representative value of a preset reference class. Using a multilevel compression method, lowest level codes are vector-partitioned by P-units at equal intervals with respect to each classified DCT block, and code books of representative vectors corresponding to the partitioned vectors are provided.

Abstract: A method and apparatus for compression encoding successive input images into a plurality of sync blocks which are sequentially recorded on a record carrier, comprises digitally processing each of the input images in accordance with a first image compression encoding technique so as to provide a first digital signal representative of a low resolution version of each of the input images. The input images are also digitally processed in accordance with a second image compression encoding technique which is different from the first image compression encoding technique so as to provide a second digital signal representative of a higher resolution version of each of the input images. Consecutive portions of both of the first and second digital signals are combined into sequential sync blocks which are then sequentially recorded on a record carrier.

Abstract: A digital communication system includes a data encoder responsive to a digital data stream for forming sequential data blocks from the digital data stream which are representative of information to be communicated. A synchronization data encoder responsive to the digital data stream, generates sequential sync blocks including synchronization data which are related to the sequential data blocks, as well as a prescribed digital sequence. A multiplexor responsive to the sequential data blocks and the sequential sync blocks, combines the blocks in an alternating manner so as to form a block-coded information signal. A modulator responsive to the block-coded information signal, provides a modulated block-coded information signal to a communication channel. A communication channel receiver includes a synchronization data recovery circuit responsive to the modulated block-coded information signal for detecting the prescribed digital sequence and providing at an output a reference signal in response to the detection.

Abstract: A frequency-multiplexed video signal is generated in which a color-under signal and a second under signal are linearly combined with at least partially overlapping frequency spectra to form a composite under signal for an FM luma signal. The frequency-multiplexed video signal is suited for recording on magnetic tape using helical scanning methods and for being played back from the magnetic tape using helical scanning methods. The second under signal is generated in such way that line-comb filtering can be used during playback to separate color-under signal and second under signal each from the composite signal despite their frequency spectra being at least partially overlapping in the composite signal.

Abstract: Apparatus is disclosed for processing video information which is reproduced from a magnetic recording medium in a video cassette recorder. The luminance portion of the video signal, which is "folded" about a sampling frequency carrier before recording on magnetic tape, is unfolded after being read from the magnetic tape to restore the bandwidth of the signal, and is applied in parallel through horizontal and vertical comb filters. The combined output of the horizontal comb filter and the vertical comb filter may include incompletely cancelled horizontal and vertical components of the folding frequency and sidebands due to the effects of picture contents. An edge detector receptive to the unfolded video signal responds to an encountered brightness edge, and generates a signal which varies the proportions of the video outputs of the horizontal and vertical comb filters in the combined output.

Abstract: A video recording/playback system includes in its recording electronics time-base correctors both for luma signal and for color-under signal, the time-base corrector for luma signal being used to facilitate comb filtering and the time-base corrector for chroma signal being used to maintain luma/chroma tracking during recording. The video recording/playback system includes in its playback electronics time-base correctors both for played-back luma signal and for played-back color-under signal, the time-base corrector for played-back luma signal being used to facilitate comb filtering and the time-base corrector for played-back chroma signal being used to maintain luma/chroma tracking during playback. With appropriate switching, the same pair of time-base correctors can be used in both the recording and the playback electronics of a video recording/playback system.

Abstract: An image carrier for storing video information including a plurality of slant tracks recorded thereon, wherein each of the tracks is characterized as including a predetermined number of sync blocks defining a predetermined track length, wherein each of the sync blocks is divided into first and second portions storing respective first and second digital signals coded therein. The first digital signal permits reconstruction of an input image during a trickplay mode of operation while the second digital signal permits reconstruction of an input image with a comparable resolution during a normal play mode of operation. On the average, the first digital signal of each sync block represents a complete scan line of the input image.

Abstract: In each of various motion detectors operative on composite video signal comprising chrominance component signals as well as a luminance component signal, the chrominance component signals are suppressed with a filter that removes only diagonal high frequencies in the spatial-frequency domain. These diagonal high frequencies in the spatial-frequency domain include the chrominance signal components of the composite video signal if it is in accordance with an appropriate standard, such as that employed by broadcasters in the United States of America. Motion detection is improved by reason of including more of the spatial high-frequency components.

Abstract: A motion signal detection circuit adapted to a video recording/reproducing apparatus having a frequency unfolding circuit for unfolding a luminance signal of a high frequency component included in the luminance signal of a low frequency component into an original frequency band, comprising a prefilter for eliminating the folding carrier and sidebands thereof included in the video signal unfolded by the frequency unfolding circuit, a comb filter for filtering the output of the prefilter to detect a motion signal, an error compensation circuit for compensating the errors included in the motion signal output from the comb filter.

Abstract: An apparatus and a method for reproducing television images from recordings of folded-spectrum video signals uses a zero-crossing detector to convert an FM signal encoding folded-spectrum luminance signal to a PPM signal having the folded-spectrum luminance signal in its baseband, accompanied by the harmonics of the FM carrier and their respective sidebands. The PPM signal is digitized by an analog-to-digital converter, after passage through an anti-aliasing filter that is used to suppress only higher frequencies that would otherwise be sampled at less than Nyquist rate during digitization. Except for this anti-aliasing filtering, the suppression of the harmonics of the FM carrier and their respective sidebands is deferred until after digitization. Linear-phase digital filtering is then used to suppress the harmonics of the FM carrier and their respective sidebands, and the folded-spectrum luminance signal supplied in response to this digital filtering is unfolded to restore it to its original full bandwidth.

Abstract: A motion signal detection circuit adapted to a video recording/reproducing apparatus having a frequency unfolding circuit for unfolding a luminance signal of a high frequency component included in the luminance signal of a low frequency component into an original frequency band, comprising a prefilter for eliminating the folding carrier and sidebands thereof included in the video signal unfolded by the frequency unfolding circuit, a comb filter for filtering the output of the prefilter to detect a motion signal, an error compensation circuit for compensating the errors included in the motion signal output from the comb filter.

Abstract: A television signal having a luminance spectrum extending from zero to f.sub.h in horizontal spatial frequencies and from zero to f.sub.v in vertical spatial frequencies is recorded on a video tape. A folded-spectrum signal is generated for recording by modulating the luminance signal onto a folding carrier of (f.sub.h /2, f.sub.v /2) complex spatial frequency. This is done by heterodyning the luminance signal with a folding carrier wave and then selecting as said folded-spectrum signal only the baseband portion of the resulting signal. At least when there is change between successive television images, the luminance signal is pre-filtered by a low-pass spatial filter that separates the two-dimensional image spectral domain into a pass band region and into an attenuation band region. Each point in the passed region has a corresponding mirror point in the attenuated region as mirrored about a complex spatial frequency (f.sub.h /4, f.sub.v /4) in both horizontal and vertical directions.

Abstract: A method and apparatus for detecting image motion in a television signal obtained by conversion of film images to a sequence of television video fields using the 2-3 film pulldown technique, comprising generating a plurality of interim motion detection signals which are always based upon a comparison of image points in the video signal which are spaced two sequential fields apart, and gating the plurality of interim motion detection signals together in order to generate a final motion detection signal.

Abstract: A video recorder for recording composite video signals includes an analog to digital converter for digitizing samples of the composite video signal being recorded. A sync separator separates horizontal synchronizing information from the composite video signal being recorded. Filtering separates the chrominance information portion of the composite video signal being recorded, and a down-converter mixes that separated chrominance information with a nervous carrier signal thereby to generate a color-under signal. A controlled oscillator generates a succession of pixel clock signals at a rate the frequency and phase of which are determined in accordance with an oscillator control signal, the rate being more than twice the frequency of the nervous carrier signal and setting the rate of the sampling by the analog to digital converter. A counter counts the number of pixel clock signals supplied by the controlled oscillator, and a frequency divider divides the count by a prescribed factor.

Abstract: An improved video signal recording system for recording a full bandwidth video signal on a limited bandwidth medium is disclosed. The recording system includes an encoder, coupled to an input terminal, for adaptively processing a composite video signal in response to a motion representative signal, and producing two signals; a luminance signal, having attenuated high frequencies subsampled so as to be folded into a spectral hole in the low frequencies, and being bandwidth limited to the limited bandwidth of the recording medium; and a combined signal including a chrominance and a motion component. Luminance signal recording circuitry records the folded luminance signal on the medium and chrominance signal recording circuitry records the combined chrominance and motion signal on the medium. An improved video signal playback system for reproducing such a prerecorded video signal is also disclosed.

Abstract: A system for expanding/compressing a video signal includes a dual-port memory having read and write address inputs and a video signal input. A pixel counter provides a pixel location signal to the write address input of the dual-port memory, and to a programmed memory device (e.g., a PROM) including a look-up table. The memory device is programmed to provide a time expanded/compressed version of the pixel location signal in accordance with a programmed time expansion/compression factor, which is applied to the read address input of the dual-port memory. A time expanded/compressed video signal is developed at the output of the dual-port memory.

Abstract: A widescreen television signal having left side, right side and center panel information is converted into a signal compatible with a standard television system, such as NTSC. In the compatible signal, center panel information is expanded to occupy the standard display region seen by a viewer, side panel low frequency information is compressed into the horizontal overscan region, and side panel high frequency information modulates an alternative subcarrier other than the chrominance subcarrier.

Abstract: The present application discloses a video signal processing apparatus for minimizing cross-color and cross-luminance interference in a composite video signal. A first filter is coupled to a color difference signal input terminal and generates a signal occupying a first region of a predetermined spatio-temporal frequency space. A second filter is coupled to a brightness signal input terminal and generates a signal occupying a second region of the predetermined spatio-temporal frequency space exclusive of the first region. An encoder forms a composite video signal from the filtered color difference and brightness signals such that they occupy mutually exclusive spatio-temporal frequency spaces. A television receiver for decoding the composite video signal is described which comprises the serial connection of a vertical-temporal filter and a horizontal filter.

Abstract: A progressively scanned video signal is encoded into temporal sum and difference components for transmission. The sum signal is temporally filtered, decimated and time expended to be compatible with interlaced receivers. The difference signal, also temporally filtered, decimated and time expanded, is conveyed via single or separate channels with the sum signal to a progressive scan receiver for reconstitution of the original progressive scan signal. Modified quadrature amplitude modulation is used to convey the sum and difference signals in a common channel.