Abstract: In a system for synchronizing video signals using a sampled signal having a sampling cycle, the system includes a coarse offset module configured to receive a first input signal and a second input signal and to alter an offset of the first and second input signals to produce a first intermediate signal and a second intermediate signal offset relative to each other by an integer multiple of the sampling cycle and the system further includes a fine offset module coupled to the coarse offset module to receive the first and second intermediate signals and configured to alter an offset between the first and second intermediate signals relative to each other by an amount less than the sampling cycle to produce a first output signal and a second output signal.

Abstract: A apparatus and apparatus for compensating for video insertion loss due to transmission over long twisted pair cable lines is presented. Transmission of video over twisted pair cable is advantageous because of its superior cost advantage over coaxial cable. However, twisted pair cables have significant loss characteristics at the higher frequencies (i.e., broadband) compared to coaxial cables. At a transmitter station, the video signal is amplified in the high frequency region for possible skin effect losses thereby brute forcing the high frequency components to the receiving station. At the receiver station, the video signal is further compensated for diffusion line and skin effect losses. The total skin effect compensation applied in both the transmitter and receiver stations is such that the square root of frequency characteristics of skin effect losses is compensated for.

Abstract: A passband equalizer that performs blind equalization upon a complex signal, e.g., a vestigial sideband (VSB) signal, without using a training sequence. The passband equalizer contains a decision directed equalizer (DFE) that operates upon separate in phase (I) and quadrature phase (Q) signals using a filter for the I signal and a filter for the Q signal without using filters for cross components of the I and Q signals. As such, the DFE contains approximately half of the multipliers and adders that are used in prior art DFEs.

Abstract: The delay circuit composed of plural flip-flops converts an input data into plural data 110-0˜110-n having delays of 1˜n clocks, which are inputted to the selector of the selector circuit. The counter counts the pixel number per one line of the input data, and supplies a discrete value signal indicating the counted pixel number to the judgment circuit of the selector. The judgment circuit calculates a difference between the standard pixel number and the pixel number that the discrete value signal indicates, and calculates a new delay to the delay circuit on the basis of this calculated difference. The selector outputs an output data based on the new delay calculated. With a simplified circuit configuration as above, the pixel number for each line will be regulated into the standard pixel number.

Abstract: An adaptive channel equalizer for a digital television receiver includes memory for storing channel characterization information for each received channel, from each time the channel is tuned to until the next time the same channel is tuned to. The stored information is retained even if operating power to the receiver is interrupted. Whenever operating power is restored to the receiver after interruption and whenever a channel is tuned to again after having tuned to another channel, the previously stored channel characterization for the currently tuned channel is retrieved from memory. The retrieved channel characterization is used to calculate initial filter coefficients for the adaptive channel equalizer.

Abstract: A system for filtering digital television signals is provided. The system comprises a generator for providing a first data sequence to a private data packetizer, and a transmitter for transmitting the packetized first data sequence in a data channel of a digital television signal. The system further includes a receiver for receiving the digital television signal and recovering the first data sequence. The receiver includes a channel estimator for providing an estimate of channel characteristics, such as estimated channel impulse estimate and estimated noise variance. The receiver further includes an adaptive equalizer filter having an input for receiving the digital television signal and an input for receiving adaptive filter coefficients. The receiver further includes a coefficient processor for calculating adaptive filter coefficients based on the channel estimate, and providing the adaptive filter coefficients to the adaptive equalizer filter.

Abstract: Training signal for channel equalization is located in the initial data segment of each DTV data field and in the nineteenth scan line of each NTSC field. Arranging for training signal separated from plural PN sequences near the beginnings of the initial data segments of DTV data fields improves post-ghost detection capability in the DTV system. In receivers for receiving NTSC signals and DTV signals, arranging for training signal to be separated from plural PN sequences near the beginnings of the nineteenth scan line of each NTSC field facilitates the same ghost-cancellation and channel-equalization filtering being used both during the reception of NTSC signals and during the reception of DTV signals.

Abstract: Baseband DTV signals are supplied to a cascade filter connection of a transversal filter operative over many data segments and a match filter for data segment synchronizing (DSS) signals. The accumulated random data in the cascade filter response is suppressed by coring, to generate a signal ensemble descriptive of ghosted DSS signal. The transmission channel is characterized based on this ensemble, and the coefficients of a complementary channel-equalization and ghost cancellation filter are calculated based on this characterization.

Abstract: A system and method for demodulation of an RF signal on a transmission channel is provided. The RF signal is demodulated to baseband as an in-phase (I) data signal and a quadrature (Q) data signal. A first block of I data is captured and a first block of Q data is captured. A time domain guard interval is provided in the captured first blocks of I and Q data. A complex discrete Fourier transform is performed on the captured first I and Q data blocks. An inverse frequency response for the transmission channel is determined. The inverse frequency response is multiplied by the complex discrete Fourier transform of the guard-interval protected first I and Q data blocks to generate a frequency domain product signal. An inverse Fourier transform on the product of the multiplying step is performed to generate a first equalized time domain signal. In a preferred embodiment, the method also includes using an overlapped Fourier transform and discarding a first portion of each equalized time domain signal.

Abstract: A video signal processing apparatus includes an equalizer for delaying an input color signal by an adjustable phase retardation. A low pass filter is operative for delaying the input color signal by an adjustable phase retardation. A phase detector is operative for detecting a difference between a phase of an output signal of the equalizer and a phase of an output signal of the low pass filter, and outputting a signal representative of the detected phase difference. The phase retardation provided by the equalizer and the phase retardation provided by the low pass filter are adjusted in response to the output signal of the phase detector to maintain the difference between the phase of the output signal of the equalizer and the phase of the output signal of the low pass filter at a predetermined value, for example, 90 degrees.

Abstract: A blind-equalization method and apparatus are disclosed for equalization of a channel of an HDTV receiver. The HDTV receiver comprises a rejection filter corresponding to a precoder for which precoding is implemented at a television transmitter for combating co-channel interference, wherein the television transmitter transmits a digital television signal. The HDTV receiver further comprises an equalizer having an input and an output. The equalization method comprises the steps of initiating an equalization with a blind slicing mode. The method further comprises changing the equalization to a training sequence mode upon an occurrence of a no flutter condition. While in the training sequence mode, if a flutter condition occurs, then the equalization is returned to the blind slicing mode. A determination of the occurrence of the flutter condition is based upon an estimate of a negative derivative of the Signal-to-Noise Ratio (SNR) at the output of the equalizer, dS.sub.

Abstract: A method and apparatus for the self-correcting of anti-ghosting filter coefficients is provided. A plurality of coefficients associated with an anti-ghosting filter are monitored as data is received by the filter. The plurality of coefficients are adjusted if one or more of the plurality of coefficients exceed a first value. In one embodiment, the filter is an adaptive baseband equalization filter. If the magnitude of one or more secondary coefficients of the adaptive baseband equalization filter exceed a predetermined factor of the primary coefficient, then the plurality of coefficients are adjusted. In another embodiment, the filter is a lookup table filter. If the magnitude of a coefficient in the lookup table is greater than a predetermined value, the plurality of coefficients are adjusted.

Abstract: A video signal processing system includes a circuit for detecting the delay between a luminance signal and a color signal in a video signal, and for automatically compensating for the delay. The circuit includes a Y/C separator for separating a composite video signal into the luminance signal and the color signal, and a color difference and synchronous signals separator for separating the luminance and color signals into synchronous and color difference signals. A delay circuit receives and delays the luminance signal based on a delay control signal, and outputs the delayed luminance signal to a video signal processor, which also receives the color difference signals directly from the color difference and synchronous signals separator.

Abstract: The apparatus and method described herein shows a system of determining the delay of a delayed version of a sequence of images with respect to a relatively undelayed version in a system which creates an output image signal from a plurality of input signals. The invention is also useful for comparing a given image to other images to determine the closest match, and thus the one of the plurality of input image sources from which an output image is taken.

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: In a television signal receiver, including an intermediate frequency (IF) filter (3) having an intermediate frequency filter group delay, and an intermediate frequency (IF) demodulator (5) coupled to the intermediate frequency filter (3), a correction filter arrangement (9, 13, 15) is coupled to the intermediate frequency demodulator (5) and has a programmable group delay for cancelling a group delay precorrection carried out at a transmitter and the intermediate frequency filter group delay.

Abstract: In the present invention, a drive circuit 12 drives a solid-state image-pickup element 11 in synchronism with a synchronizing signal generated by a synchronizing signal generation circuit 13, and the solid-state image-pickup element 11 issues an output signal prior to an end time of a horizontal blanking period by a time period T.sub.A. This output signal is processed in a digital signal processing circuit 14 and is issued as a picture signal. At that time, the picture signal is delayed from the synchronizing signal by a time period (T.sub.B -T.sub.A) owing to the signal processing, whereas the synchronizing signal is delayed by a delay circuit 15, in which a delay time made by subtracting a time period T.sub.A from a delay time T.sub.B of the digital signal processing circuit 14 is given, and can be issued in a proper timing for a picture signal output of the digital signal processing circuit 14.

Abstract: When transmitting an audio signal by multiplexing in a synchronous period of a video signal, a buffer memory for time axis adjustment of the audio signal is controlled. The number of audio signal samples in the buffer memory is detected in every n fields (n being a positive integer) of video signal, and when it is different from a specific value, the read or write address of the buffer memory is preset, so that the number of audio signal samples in the buffer memory is kept constant at the moment of inspection in every n fields. Besides, by inspecting the number of audio signal samples in the buffer memory in one field or more, a line providing a maximum or minimum value of the number of samples is stored, and thereafter the number of audio signal samples in the buffer memory in that line is kept constant, so that the buffer memory capacity may be utilized effectively.

Abstract: A system for filtering digital television signals is provided. The system comprises a generator for providing a first data sequence to a private data packetizer, and a transmitter for transmitting the packetized first data sequence in a data channel of a digital television signal. The system further includes a receiver for receiving the digital television signal and recovering the first data sequence. The receiver includes a channel estimator for providing an estimate of channel characteristics, such as estimated channel impulse estimate and estimated noise variance. The receiver further includes an adaptive equalizer filter having an input for receiving the digital television signal and an input for receiving adaptive filter coefficients. The receiver further includes a coefficient processor for calculating adaptive filter coefficients based on the channel estimate, and providing the adaptive filter coefficients to the adaptive equalizer filter.