Abstract: In video tape recording apparatus composite video signals are separated into their luminance and chrominance components for processing prior to recording. The luminance components are digitized, adaptively temporal and spatial filtered, and folded into a reduced frequency spectrum to generate a digital signal that is converted to analog form to modulate the frequency of the luminance carrier signal used in video tape recording. The chrominance components are converted to the color-under signals used in video tape recording. In video tape playback apparatus the color-under signals are converted up in frequency to provide chrominance components for inclusion in reproduced composite video signals.

Abstract: A system for reproducing a luminance signal from a medium containing a previously recorded luminance signal with a high-frequency portion thereof compressed in dynamic range includes a circuit for recovering that luminance signal from the medium. Filtering is done to separate the low-frequency and compressed-in-dynamic-range high-frequency portions of the recovered luminance signal from each other. A corer responds to the separated compressed-in-dynamic-range high-frequency portion of the recovered luminance signal to provide a cored high-frequency portion with expanded dynamic range and reduced noise.

Abstract: A slicer for a decision feedback error equalizer system which processes trellis encoded data using the ATSC trellis code is implemented in two parts. A first part includes a single-stage trellis decoder which estimates the value of a single bit of the symbol. The second part includes two trellis decoders each of which estimates the values of respective subsets of the symbols in the alphabet given that the single bit is zero or one. A multiplexer is responsive to the single stage trellis decoder to direct the received digital samples to one of the two trellis decoders in the second part of the slicer. An alternative slicer includes a first part which estimates two bits of the output symbols and selects from among four decoders in the second part in order to fully decode the symbols. The smart slicer can be generalized for any set-partitioned code with or without a feedback convolutional code.

Abstract: An encoder separates luminance and chrominance signal components of a composite video signal. The frame-to-frame changes in the luminance signal are detected, and a motion signal is derived therefrom. The higher frequency portion of the luminance signal is adaptively de-emphasized in amplitude and folded into the spectrum of the lower frequency portion of the luminance signal, to generate a folded-spectrum luminance signal for modulating the frequency of a luma carrier. In a combined signal, suitable for magnetic recording in accordance with a modified VHS standard, the chrominance signal is translated in frequency to generate a color-under signal in a frequency band below that occupied by the FM luma carrier.

Abstract: In video tape recording apparatus composite video signals are separated into their luminance and chrominance components for processing prior to recording. The luminance components are digitized, adaptively temporal and spatial filtered, and folded into a reduced frequency spectrum to generate a digital signal that is converted to analog form to modulate the frequency of the luminance carrier signal used in video tape recording. The chrominance components are converted to the color-under signals used in video tape recording. In video tape playback apparatus the color-under signals are converted up in frequency to provide chrominance components for inclusion in reproduced composite video signals.

Abstract: A television receiver for processing both analog television signals and digital television signals. Specifically, the television receiver contains a RF/IF front end, an analog-to-digital converter that samples a near baseband signal using a "free running" sample rate, and a combined demodulator that demodulates the digitized analog television signals or the sampled digital television signals. The combined demodulator recovers both pilot and pix carriers as well as provide a passband adaptive equalizer that removes ghosts from analog television signals and intersymbol interference from digital television signals.

Abstract: A magnetic tape recording with a new signal encoding format, apparatus for recording this format and reproducing apparatus for reproducing signals from this format. A standard VHS signal is recorded as a first set of parallel slant tracks having a predetermined spacing between each slant track. A high definition television signal is recorded in pairs of slant tracks of a second type that flank a slant track of the first type and are narrower in width than the slant track of the first type they flank. Additionally, the azimuth angle of the tracks of the first type alternates between different predetermined values for successive tracks, and the azimuth angle of the tracks of the second type differ both from the azimuth angle of the tracks of the first type which they flank, and from the azimuth angle of the tracks of the second type which are positioned next to them in the space between tracks of the first type.

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: A video signal processing system has luminance signal and a chroma carrier modulated with chrominance information. The system includes circuitry responsive to the chroma carrier for generating a phase alternating carrier having a phase alternating from field to field; circuitry for modulating a selected luminance signal on the phase alternating carrier and circuitry for adding the modulated phase alternating carrier to the chroma carrier modulated with chroma information.

Abstract: A receiver for demodulating multiple digital modulation formats including vestigial sideband (VSB), quadrature amplitude modulation (QAM), and offset QAM (OQAM). The receiver includes a timing recovery circuit that produces accurate timing information for each modulation format and a signal processor for adaptive equalization and quantization of each modulation format. The adaptive equalizer is a passband equalizer that performs blind equalization using a feed forward equalizer and a decision feedback equalizer.

Abstract: A video signal recording system is disclosed which includes a circuit for generating a control signal representative of the level of the high-frequency portion of a full-bandwidth luminance signal. An adaptive deemphasis circuit reduces the level of the high-frequency portion of the luminance signal in response to the control signal. A folding circuit folds the high-frequency portion of the deemphasized luminance signal into the low-frequency portion. The folded deemphasized luminance is combined with the control signal and recorded on the video tape. A video signal playback system is disclosed which includes a circuit for separating the previously recorded control signal from the previously recorded folded deemphasized luminance signal. An unfolding circuit unfolds the played back luminance signal to produce a wide bandwidth deemphasized luminance signal. An adaptive reemphasis circuit boosts the level of the high-frequency portion of the unfolded luminance signal in response to the separated control signal.

Abstract: A system for reproducing a luminance signal from a medium containing a previously recorded luminance signal with a high-frequency portion thereof compressed in dynamic range includes a circuit for recovering that luminance signal from the medium. Filtering is done to separate the low-frequency and compressed-in-dynamic-range high-frequency portions of the recovered luminance signal from each other. A corer responds to the separated compressed-in-dynamic-range high-frequency portion of the recovered luminance signal to provide a cored high-frequency portion with expanded dynamic range and reduced noise.

Abstract: A dual chrominance signal processor is disclosed which may be used in a combination television and video cassette recorder system, for example. Such a chrominance signal processor includes first and second modulated chrominance signal sources, and first and second demodulating carrier signal sources, corresponding to the first and second modulated chrominance signal sources, respectively. A demodulator is responsive to a chrominance signal and a demodulating carrier signal, for demodulating the chrominance signal. A signal selector is coupled between the signal sources and the demodulator, and selectively couples one of the first and second chrominance signal sources, and the corresponding one of the first and second demodulating carrier signal sources, to the demodulator in response to a selection signal.

Abstract: A magnetic tape recording with a new signal-encoding format, apparatus for recording this format and reproducing apparatus for reproducing signals from this format. A standard VHS signal is recorded as a first set of parallel slant tracks having a predetermined space between each slant track. A high definition television signal is recorded in pairs of slant tracks of a second type that flank a slant track of first type and are narrower in width than the slant track of first type they flank. Additionally, the azimuth angle of the tracks of first type alternates between different predetermined values for successive tracks, and the azimuth angle of the tracks of second type differ both from the azimuth angle of the track of the first type they flank and from the azimuth angle of the tracks of second type which are positioned next to them in the space between the tracks of first type.

Abstract: A numerical voltage controlled oscillator comprising an integrator for generating an estimated sine waveform and an estimated cosine waveform from a variable control signal; a normalizer, connected to the integrator, for generating a normalization factor from the estimated sine waveform and the estimated cosine waveform; and a multiplier, connected to the normalizer, for multiplying the normalization factor with the estimated sine waveform and the estimated cosine waveform. The multiplication of the estimated sine waveform and the normalization factor produces the sine waveform and the multiplication of the estimated cosine waveform and the normalization factor produces the cosine waveform. The frequency and phase of the sine and cosine waveforms vary with changes in amplitude of the variable control signal.

Abstract: A system for reproducing a luminance signal from a medium containing a previously recorded luminance signal with a high-frequency portion thereof compressed in dynamic range includes a circuit for recovering that luminance signal from the medium. Filtering is done to separate the low-frequency and compressed-in-dynamic-range high-frequency portions of the recovered luminance signal from each other. A corer responds to the separated compressed-in-dynamic-range high-frequency portion of the recovered luminance signal to provide a cored high-frequency portion with expanded dynamic range and reduced noise.

Abstract: A digital information receiver having a single oscillator providing a clock signal to the receiver circuitry. The receiver contains, in addition to the oscillator, an input signal processor, a symbol timing loop, a demodulator, a transport decoder, a transport timing loop, one or more applications decoders and a presentation device. The input signal processor digitizes an input signal and resamples the input signal using an interpolator such that the input signal is optimally sampled. The resampling is controlled by a symbol timing loop. In a first embodiment, the transport timing loop controls the frequency of the oscillator using transmitter timing information contained in the received signal. In a second embodiment, the oscillator is a free running oscillator and the transport timing loop controls a numerically controlled counter that, in turn, controls presentation timing of the information carried by the information in the input signal.

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: A video tape includes a plurality of parallel slant tracks formed therein. Each track includes a plurality of successively recorded sync blocks. In each sync block, a respective portion of a first digital signal recorded therein represents a predetermined portion of an input image with relatively low resolution, and a respective portion of a second digital signal recorded therein represents substantially the same predetermined portion of the input image with relatively high resolution. Successive sync blocks include consecutive portions of the first digital signal, which portions correspond to spatially adjacent portions of the input image. Preferably, each sync block includes a fixed number of bits of the first digital signal, which is decodable without reference to any image coded signal from other sync blocks.

Abstract: A digital signal proces sing system for receiving and processing a high definition television signal, eg., in a Pulse Amplitude Modulation (PAM) format, includes a filter for rejecting interferer signals such as a narrowband continuous wave NTSC co-channel interferer. In an illustrated embodiment the rejection filter is a digital FIR filter (18) located after a (de)rotator (16) in a carrier recovery network (16, 20, 24, 26, 28). The filter exhibits a zero throughput delay bandpass response with attenuation notches for rejecting NTSC co-channel picture and chrominance baseband carrier frequencies.