Abstract: In a single-chip multistandard video modulator arrangement in which audio signals for transmission with video signals are first modulated onto a subcarrier and then combined with the video signals for modulation onto a VHF or UHF main carrier, the modulated subcarrier signals are passed through a high-pass filter before being combined with the video signals in order to reduce the amplitude of any audio frequency components, and the resulting variations in main carrier amplitude, which tend to produce "sound in vision" effects.

Abstract: The present invention relates in general to a digital-signal processing apparatus as well as a digital-signal processing method and, in particular, to a jitters removing apparatus as well as a jitters removing method. In the apparatus provided by the present invention, a TV signal received by a tuner or a video signal supplied by a VCR is fed to a moving-average correction circuit and a first FIFO circuit. In a correlation-value computing circuit, correlation between a carrier chrominance signal extracted by the moving-average correction and a carrier chrominance signal delayed by a second FIFO circuit by a predetermined time is found and a correlation value having a maximum absolute value is supplied to a quantization circuit. In the quanitization circuit, the quantization value is quantized to determine a class code. Then, coefficients for taps indicated by the class code are read out from a coefficient ROM unit and supplied to a linear first-order weighed-sum computing circuit.

Abstract: A method and apparatus for reducing video crosstalk in a data carrier located within a lower vestigial sideband (VSB) of a standard television signal. Specifically, an apparatus according to the invention comprises a single bandpass filter for conditioning a VSB television signal, and a frequency interleaver for spectrally adding the data carrier to the lower VSB of the standard VSB video signal. The filter removes removing video components from the lower VSB of a standard VSB video signal, including frequencies greater than the highest frequency nominally associated with the lower VSB of the standard television signal, illustratively 250 Khz above the nominal VSB bandedge. The filter also boosts frequencies in a spectral boost region within a passband for boosting region. The boosted frequencies comprise image frequencies associated with the non-VSB spectrum attenuated by the filter.

Abstract: A method and apparatus for improved interference rejection, where the rejection is being accomplished by an IIR filter at the transmitter with complementary characteristics to an FIR filter of the receiver, such as a Tomlinson-Harashima transmit-precoder. The improvement is accomplished by providing the ability to preset the transmit and receive filters to the same state, thereby allowing for subsequent receptions to be deterministic. This method and apparatus is particularly useful for correcting for time-varying interference through the use of repeatable, deterministic, training sequences.

Abstract: A high definition television receiver includes a comb filter for receiving trellis coded HDTV data, the comb filter turning on if there is interference from an NTSC signal having a co-channel in the data to thereby remove the interference, and the comb filter turning off if there is no interference to thereby pass the received HDTV data; a determining part for determining if the comb filter is turned on/off and providing a comb filter ON/OFF signal according to the determination result; and a united trellis decoder having united state transitions of a partial response trellis decoder and an optimal trellis decoder, the united trellis decoder having a signal group divided into signal groups of the partial response trellis decoder and the optimal trellis decoder, thereby operating as the partial response trellis decoder according to the comb filter ON signal and operating as the optimal trellis decoder according to the comb filter OFF signal input from the determining part.

Abstract: The present invention provides a method (200) and an apparatus (100) for spatially adaptive filtering for video encoding. The apparatus filters a video sequence prior the encoding process. The apparatus comprises a noise variance determiner (102), a local variance determiner (104), a noise visibility function determiner (106), a Gaussian kernel determiner (108), and a convolver (110). The apparatus removes noise directly from a Displaced Frame Difference, DFD, signal. This novel approach removes noise and miscellaneous high frequency components from the DFD signal without the introduction of the filtering artifacts characteristic of current techniques. By reducing the miscellaneous high frequency components, the present invention is capable of reducing the amount of information that must be encoded by the video encoder without substantially degrading the decoded video sequence.

Abstract: An image processing system uses a pseudo-random pixel interlace method and apparatus for capturing groups of pixels as image frames. This pseudo-random method eliminates the artifacts commonly present in standard regular line raster scan imaging systems. Moreover, the pixel interlacing method permits the construction of higher resolution frames from a series of orthogonal lower resolution frames. An enhancement circuit deduces information from previous pixel group frames and contributes additional detail to the pixels of the frame being processed. The format of the pixel interlaced groups permits the present invention to be used in a wide variety of normally incompatible target display rates. The present invention can also be used in a computing system as an auto-synchronizer for processing signals from different sources.

Abstract: A data register for providing data values to an n-element parallel processing array includes a memory buffer having first and second memory modules, where each module includes n columns of data values. An address decoder receives an address for accessing n data values at a time from the memory modules and asserts address values to access corresponding rows of the first and second memory modules. Select logic selects between respective columns of the first and second memory modules to retrieve the desired data values according to a predetermined order. A shift network reorders the retrieved data values, if necessary, to place them in the proper order for the processing array. The address decoder provides a select value to the select logic and a shift value to the shift network for each cycle. For purposes of horizontal decimation, the pixel values are organized into an even and an odd group, which groups are stored in the memory buffer in two separate regions separated by an address offset K.

Abstract: A co-channel interference filter and a method for reducing co-channel interference for use in a television receiver. The television receiver receives a signal transmitted from a transmitter, the received signal having an encoded digital television signal component, a co-channel interference component, and a noise component, wherein the encoded digital television signal component is characterized as an N-level vestigial sideband (VSB) signal of Reed-Solomon (R-S) encoded, byte interleaved and trellis encoded symbols c.sub.k, i (for i=1 to 12), where N corresponds to a number of levels, and further wherein each symbol c.sub.k, i is derived from original symbol bits a.sub.k, i.sup.1 and a.sub.k, i.sup.2 (for i=1 to 12), respectively. The co-channel interference filter comprises a generator for generating a characteristic coefficient .alpha. in response to a received television signal, .alpha. being dependent upon an amount of the co-channel interference and noise components present in the received signal.

Abstract: The invention comprises an optimal causal, monic (first coefficient of filter is 1) NTSC rejection filter for use at an ATV receiver which is designed to optimally process the interference caused by an NTSC co-channel signal while keeping the noise enhancement to a desirably low value. In other words, the design method gives the filter with the BEST NTSC rejection capability for a given noise enhancement.

Abstract: In a digital video signal recording and reproducing apparatus using bit rate reduction coding, information multiplexed to each record block is selected depending on the reproducing process applied to reproduce record blocks. When error correction is carried out and then, error concealment is applied to any record block having an error uncorrectable by the error correction, error concealment information indicating that the error concealment was carried out is multiplexed to the record block to be outputted. Also, since the continuity of bit rate reduction encoded data may be broken by concealing a part of record blocks, decoding information for controlling the decoding of bit rate reduction encoded data is multiplexed to the record block to be outputted. When an error concealment is not carried out in the bit rate reduction encoded state, an error flag indicating that an error exists is multiplexed to the record block to be outputted.

Abstract: A partial response Trellis decoder that performs trellis coded modulation in a high definition television (HDTV) having a specific and detailed configuration and includes a distance mapper for calculating first, second, third and fourth Euclidean distances between the input signal and a reference value; a Viterbi decoder for Viterbi decoding the first, second, third and fourth Euclidean distances calculated by the distance mapper; a first delay for delaying and outputting the Yiterbi decoded data for each Euclidean distance; a ruler selector for selecting a ruler type signal based on the signals output by the first delay; and a slicer for slicing the selected ruler type signal and the input signal.

Abstract: A novel pre-processing filter apparatus for use in an image encoding system, capable of adaptively filtering an input digital video signal, comprises a circuit for delaying a current frame of the input digital video signal by one frame interval; a circuit for generating a difference signal representing the difference between averaged pixel value for N.times.N pixels of the delayed previous frame and an averaged pixel value for N.times.N pixels of the current frame, at an identical area of the previous frame and the current frame; two or more filtering circuits arranged in parallel for filtering the input digital video signal, respectively, each of the filtering circuits having different cutoff frequencies; and a control circuit for generating one of the filtered digital video signals in response to the difference signal.

Abstract: A ghost canceling reference signal transmission and reception system utilizes a ghost canceling reference signal including a zero to seventy IRE step followed by a seventy to zero IRE (sin x)/x step.

Abstract: A channel equalization system of a VSB transmission system for a HDTV which can correct phase errors by using composite filters as well as by using general data even in a period having no training sequence. The channel equalizer for a HDTV includes, a composite filter part for making the input signal applied from outside produced as a I signal and a Q signal, filtering the I signal and the Q signal according to composite filter coefficients, and transmitting the filtered I and Q signals as first and second output signals.

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: A digital data transmission system for signals in the areas of interference having a high degree of vertical correlation comprises a transmission frame including a plurality of vertically arranged repetitive horizontal data segments each including a fixed number of subsegments with symbols of individual subsegments being vertically correlated on different data segments. The vertically correlated symbols are further interspersed in the transmission frame for guarding against horizontally correlated burst noise. A Reed-Solomon correction system is incorporated for each data segment in the transmission frame.

Abstract: A selective intermodulation correction system which can correct for in-band intermodulation products which are formed in a high end of a video sideband region generated in the common amplification of a television signal. The selective intermodulation correction system operates to generate an intermodulation product which is equal in amplitude but opposite in phase to in-band intermodulation products formed at the high end of the video sideband region. By combining such a signal to a conventionally corrected television signal, the in-band intermodulation products formed in the high end of the video sideband region can be cancelled.

Abstract: A circuit is provided for precorrecting an aural carrier signal in a common amplifier system in a television transmitter wherein an aural frequency signal and a visual signal are commonly amplified. The precorrecting serves to minimize cross-modulation distortion of the aural carrier caused by the common amplification. A visual carrier signal is modulated by a video baseband signal to provide a modulated video signal from which there is provided a sampled video signal. This sampled video signal is supplied to an aural corrector which provides from the sampled video signal a phase correction signal and an amplitude correction signal. The phase correction signal and amplitude correction signal are used to modulate an aural carrier signal to provide a precorrected aural signal which is then combined with the video signal to provide a combined signal.

Abstract: A cochannel interference filter for a HDTV transmission system comprising a post-comb filter. The post-comb filter comprises first and second feedforward circuits. The first feedforward circuit includes a first adder and a first delay circuit. The first adder has a first input connected to an output of a data clock recovery circuit. The first delay circuit has an input connected to the output of the data clock recovery circuit and an output connected to a second input of the first adder. The second feedforward circuit includes a second adder and a second delay circuit. The second adder has a first input connected to an output of the first adder. The second delay circuit has an input connected to the output of the first adder and an output connected to a second input of the second adder. Also, the post-comb filter comprises third and fourth feedforward circuits. The third feedforward circuit includes a third adder and a third delay circuit.

Abstract: A magnetic recording correction circuit for a video tape recorder comprises a first multiplier supplied with a first signal to output a signal having a frequency which is twice as high as that of the first signal; a second multiplier supplied with a second signal and a first multiplier output signal outputted from the first multiplier to output a correction signal having a component of a sum frequency of the second signal and the first multiplier output signal and a component of a difference frequency therebetween; an adding circuit for adding the first and second signals and the correction signal; and a phase shifter provided on the output side of the second multiplier to exert a phase characteristic on the correction signal with respect to the first and second signals.

Abstract: The present invention comprises a method for characterizing a multi-path signal transmission in transmitting a plurality of signals with a plurality of cyclic fields each including a plurality of horizontal scanning periods wherein some of the scanning periods are vertical blanking periods. The method comprising the steps of: (a). transmitting periodically in a plurality of the scanning periods in one of the fields at least two reference signals each with a different predefined signal characteristics; (b). receiving the plurality of signals including the reference signals; and (c). processing the received signals including the received signals of reference signals for detecting a multi-path channel delay of the signal transmission.

Abstract: A video signal encoder uses an encoding system such as that developed by the Moving Picture Experts Group (MPEG). A key component of this encoding system reduces the number of bits required to encode the video signal. Apparatus according to the present invention, filters out high diagonal frequencies in the spatial domain of a video signal. Specifically, two dimensional (2-D) filtering is performed on frames of a video signal to filter out high diagonal spatial frequencies before the video signal is separated into blocks. These blocks may be encoded in fewer bits due to elimination of noise components and other image components having high diagonal frequencies.