Abstract: Composite video signal and a relatively low power phase-shift-keyed (PSK) signal encoding digital information are transmitted on respective phases of a video carrier in quadrature with each other. Selected scan lines of the composite video signal contain ghost-cancellation reference (GCR) signals. A digital signal receiver performs a first detection of the video carrier modulated in the two phases, down-converting to an intermediate-frequency (IF) signal. This IF signal is selectively amplified prior to respective second detection of the down-converted video carrier by in-phase and quadrature-phase synchronous video detectors. A first cascade filter connection of a first ghost-cancellation filter and a first equalization filter follows the in-phase video detector, and a second cascade filter connection of a second ghost-cancellation filter and a second equalization filter follows the quadrature-phase video detector.

Abstract: An adaptive method for suppressing video signal echoes in television equalizers including digital filters having coefficients which are updated in an adaptive and iterative manner using a modified LMS (Least Mean Square) algorithm until the difference, or output error, between a target output signal, called the reference signal, and an outgoing signal from the equalizer is gradually reduced.

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: An improved equalization apparatus includes updating circuit for generating, in response to the received television signal and the error signal, a set of updated filter coefficients as the set of the filter coefficients for the equalizer filter, which comprises: a shift register for storing and shifting a data sample to provide a set of the data samples; a multiplier for multiplying a error signal with the set of the data samples to provide a set of error weighted data samples; a scaling circuit, in response to a blind mode signal, for scaling down the set of error weighted data samples with a first scale value in order to generate a first set of scaled error weighted data samples and, in response to a decision mode signal, for scaling down the set of error weighted data samples with a second scale value to generate a second set of scaled error weighted data samples; an adder for adding the first or the second set of scaled error weighted data samples to a set of previous filter coefficients in order to produ

Abstract: Digital data having a symbol rate that is a multiple of horizontal scan rate are buried in broadcast television signals. In a digital signal receiver the data are separated from composite video signal by quadrature video detection followed by comb filtering. The comb filtering is most economically realized by digital sampling at symbol rates. The regeneration of clocking signals at symbol rate, and at multiples of symbol rate where oversampling analog-to-digital conversion (ADC) techniques are employed, is done using a controlled oscillator with automatic frequency and phase control (AFPC) responding to the horizontal synchronizing pulses transmitted in the broadcast television signals. The horizontal synchronizing pulses are usually much larger than noise, so the controlled oscillator frequency and phase is rapidly adjusted following energization or channel change of the digital signal receiver.

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: An image signal processor for processing a received image signal. The received image signal can be at least one of an analog image signal and a digital image signal. The processor converts the analog image signal into first digital image data and converts the digital image signal to second digital image data. The processor selects at least one of the first and second digital image data as input image data. The input image data is then decode-processed based upon a selected at least one of a plurality of processing programs. The selected at least one processing program corresponds to the selected at least one of the first and second digital image data.

Abstract: A signal input in a raster scan format is entered into one-dimensional digital filters. An output of the one-dimensional digital filter is multiplied in a multiplier. Outputs of one-dimensional digital filters are provided to delay circuits to generate a time delay in a direction perpendicular to the raster scan direction. The output of the multiplier and the outputs of the delay circuits are added by adders. A one-dimensional digital filter of the vertical direction is decomposed in a manner more simple than in the horizontal direction to reduce delay time between input and output.

Abstract: A circuit architecture suitable for use in a television receiver which effectively performs a ghost or echo cancellation procedure on post echo components and pre echo components occurring within the transmission channel. The apparatus features a filter circuit architecture which can be configured under programmed control so as to partition groups of its filter sections to form IIR filters and FIR filters. The filter architecture is suitable for use in multi-circuit configurations and can be used with clustering algorithms to increase the efficiency and optimize the use of the available circuit architecture.

Abstract: A ghost canceler having an adaptive signal level adjustment function includes an amplifier for amplifying an analog video signal provided to an analog-to-digital converter and a microprocessor for detecting the peak-to-peak value of the input video signal using a level difference between an input ghost cancellation reference signal contained within the analog video signal and a preset ghost cancellation reference signal and for determining an amplification coefficient using the detected peak-to-peak value. The analog-to-digital converter converts the amplified video signal to produce maximum bit resolution, which thereby permits ghost cancellation performance in the ghost canceler to be enhanced and prevent a loss in displayed video quality.

Abstract: A ghost cancellation system for filtering out ghosts in a received video signal including an active filter having a filtering function defined by a first set of coefficients (ak.sub.old) and having a input and a output. A transmitted ghost cancellation reference (GCR) signal is applied to the input of the active filter during a vertical blanking period to generate a filtered GCR signal at the output of the active filter. The filtered GCR signal is compared with a ghostless GCR signal to obtain an error signal, and the filter coefficients are adjusted based on the error signal to obtain a set of new coefficients (ak.sub.new). The active filter includes a feedforward FIR filter and an adder serially connected between the input and the output, a feedback IIR filter and a switch serially connected between the output and-the adder, the feedforward FIR filter and the feedback IIR filter having filtering functions defined by the coefficients.

Abstract: A signal dispersion cancellation structure receives incoming signal samples at an incoming rate, stores these samples in a first memory and then writes these samples at a submultiple of the incoming rate into a plurality of second memories. Each second memory is associated with a finite impulse response (FIR) filter and the second memory samples are coupled to the associated FIR filter at the incoming rate. Advantageously, apparatus is also provided which enables any sample in a second memory to be provided to the associated FIR filter and outputted therefrom at a time related to the position of any signal dispersion.

Abstract: The present invention relates to a television ghost canceling device applied with a ternary sequence ghost cancellation reference signal, which comprises: a ternary sequence generating section included in a transmitting section of television system and for generating a training signal inserted within a vertical flyback time period of video signal to be modulated in radio frequency; a demodulating section included in a receiving section of television system and for receiving a transmission signal of the transmitting section and for demodulating to an original video signal; a line selecting section for selecting a line inserted with a training signal of vertical flyback time periods of video signal demodulated at the demodulating section; a memory stored with a ternary sequence reference signal corresponding to a training signal generated at the ternary sequence generating section; a cross-correlating section for computing a cross-correlation of the reference signal and the training signal whereby finding out a

Abstract: A method and apparatus for cancelling a ghost generated during a transmission of a video signal in a multi-path channel, which can accurately detect the start signal of the ghost cancelling reference signal at a receiving end when the ghost cancelling reference signal and a pedestal signal are inserted at a transmitting end into an 8-field to thereby be continuously transmitted.

Abstract: A new technique for channel characterization for Advanced Compatible TV (ACTV) broadcasting systems is hereby proposed that conforms to the current practice of transmitting a ghost cancellation reference (GCR) signal during the vertical blanking interval (VBI). A copy of the GCR signal is stored at the receiver, and is used to extract the effective ghost channel parameters via digital signal processing techniques. A pair of equi-length, binary (.+-.) sequences is said to be complementary if the sum of the linear autocorrelation functions of the sequences is identically zero for all shifts other than zero, and provides a high correlation gain at zero shift. Such sequences can be sequentially transmitted on the allotted VBI line in the appropriate fields, along with pairwise constant signals in the corresponding fields of a basic eighth field sequence. To conform to the positivity constraint of the transmitted signal for NTSC compatible systems, each complementary sequence is transmitted on a pedestal.

Abstract: A waveform equalizing system includes a clock reproducing phase locked loop circuit for reproducing a clock signal from a television signal; a transversal filter; a first selector circuit for alternatively passing the television signal or an output of a first memory to the transversal filter; a CPU for extracting reference signals contained in the television signal from the input and output of the transversal filter through two second memories respectively and for performing a synchronous addition of the same; the first memory for storing a reference signal processed by the synchronous addition; and a second selector circuit for alternatively delivering the television signal or an output of the transversal filter in response to a control signal from the CPU.

Abstract: Digital ghost eliminating filters incorporated in a ghost canceling circuit are responsive to weighted coefficients for canceling ghost components of a digital video signal assigned to a selected channel for a clear video image, and has an auxiliary receiving circuit sequentially tuned in other channels so as to previously produce sets of weighted coefficients for non-selected channels, thereby immediately supplying one of the sets of weighted coefficients to the digital ghost eliminating filters when a main receiving circuit is tuned in another channel.

Abstract: A system is disclosed for cancelling ghosts including I daisy chained variable delay elements, the first of which receives a video signal. J multiplexers are also provided, each of which has at least one input connected to the output of each of the I variable delay elements. A transversal filter element is connected to the output of each multiplexer for filtering the delayed video signals selected by the corresponding multiplexer connected thereto. Finally, an adder is provided for adding together the filtered video signals outputted by the transversal filter elements.

Abstract: A ghosts removal apparatus for removing a waveform distortion and ghost in television receivers and other various types of image apparatus, can exclude the influence of random noise when ghost is removed, and can favorably remove minute ghost components. A multiplication ratio setting circuit has a second judgment circuit in which a number of ghost removal is counted, and a read only memory (ROM) table which outputs a gradually smaller value of a ghost detection coefficient along with the counted number larger. At the start of ghost removal processing, a large value of the ghost detection coefficient is outputted to exclude the influence of the random noise, and along with the progress of ghost removal processing, a smaller value of the ghost detection coefficient is outputted so that minute residual ghost components can be accurately detected. Accordingly, it is possible for the tap gain of the transversal filter to be set to an optimum value and for ghost to be favorably removed.

Abstract: A ghost-canceling reference signal for inclusion in a television signal is provided by cyclically inserting ones of extended-length complementary-sequence pairs into a prescribed scan line in each of the vertical blanking intervals of successive fields of the television signal. By definition, a pair of binary (.+-.1) sequences of similar length to each other are complementary sequences only if the sum of the linear autocorrelation functions of the sequences is identically zero for all shifts other than zero but provides a high correlation gain at zero shift.

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 ghost cancelling system includes a ghost cancelling IIR filter and channel modelling circuitry for generating tap weighting coefficients for programming the ghost cancelling IIR filter. The channel modelling circuitry includes means for calculating the sum of all of the generated weighting coefficient values. If the sum exceeds a predetermined value indicative of the IIR filter becoming unstable, the weighting coefficients are conditionally scaled in a manner to reduce the sum, thus tending to reduce the possibility of filter instability.

Abstract: Ghosts accompanying composite video signals are suppressed using separate filters for suppressing macroghosts and microghosts, the filtering parameters of these filters being adjustable responsive to digital programming signals generated by a computer. Computation includes data acquisition and channel characterization steps followed by a decision step for comparing the most recent set of channel characterization results with the next most recent set to determine whether stable ghosting conditions obtain. Data acquisition and channel characterization steps are repeated until stable ghosting conditions obtain, so the subsequent calculations with respect to the filter used for suppressing macroghosts are accurately performed. Where the filter suppressing macroghosts includes IIR and FIR sections for suppressing post-ghosts and preghosts, respectively, these calculations are carried out substantially on a separable basis, simplifying the calculations.

Abstract: A ghost canceller which operates at IF and utilizes a storage mode heterojunction acoustic charge transport device (SM-HACT). The signal delay provided by the SM-HACT is increased by the operation of barrier electrodes which delay the movement of charge packets across the device, thereby eliminating the need for additional digital equalization. The tap weights of the SM-HACT are determined by the operation of a fixed correlator which responds to ghosts in a predetermined training waveform.

Abstract: Disclosed is a television ghost cancellation system based on digital filtering. A baseband video signal at the output of the demodulator is lowpass filtered before being digitized at an analog-to-digital converter. The signal is then processed in digital filters to remove the ghosts. The clean digital signal is then passed to a digital-to-analog converter and lowpass filter to become a clean baseband video signal. The digital filters consist of a feedforward section and a feedback section. The coefficients of the digital filters are calculated by digital signal processor, which processes the data stored in First-In-First-Out buffers (FIFOs). The FIFOs are used as outputs, while one FIFO is used as input to the feedback section. The FIFO stores the standard ghost canceler reference (GCR) signal. Switches are controlled by a synchronization separation circuitry. The coefficients of the feedforward section are estimated by processing data stored in the FIFO.

Abstract: A horizontal edge compensation circuit includes a delay circuit for delaying an input luminance signal for a certain time, a waveform converter for differentiating the input luminance signal to take its absolute value, and reshaping the waveform of the signal, a quantization circuit for differentiating again the first differentiated signal, comparing to predetermined reference levels the first differentiated signal obtained by emphasizing a signal having a low level difference and bypassing a signal having a high level difference, and then generating a code signal to quantize the second differentiated signal, a gain controller for selectively multiplying the reshaped signal according to the code signal, and controlling the degree of horizontal edge compensation, and an adder for adding the luminance signal delayed for a certain time in the delay circuit to the horizontal edge compensation signal output from the gain control portion.

Abstract: A crosstalk detector for detecting the crosstalk of signals optically read from a recording medium having a plurality of tracks. The read signal levels between adjacent tracks at the positions where crosstalk detecting signals are recorded are compared and used to calculate a quantity of crosstalk of the read signals.

Abstract: There is provided a ghost cancelling method and apparatus in which a video signal is input to a transversal filter to generate a ghost correction signal and the ghost correction signal is mixed with the original video signal to automatically cancel a ghost. To improve the ghost cancelling speed, a correlative operation is performed between the video signal input and a ghost cancelling reference signal, to thereby determine an initial filter coefficient of the transversal filter.

Abstract: A television ghost removal apparatus comprises a transversal filter that receives input television signals, compensates waveform distortion included in the signals, and removes a ghost component; a waveform extractor that extracts signal waveforms of predetermined periods that include reference signals for ghost detection from the television signals; a coefficient setter that compares reference waveform signals and the extracted signal waveforms to obtain error signals, and sets coefficient data corresponding to the error signals, and in accordance with this coefficients data, changes filter coefficient of the transversal filter; a band limiter means for removing unnecessary high-region components included in the coefficient data, and supplying the coefficient data from which the unnecessary high-region components have been removed to the transversal filter means, the unnecessary high-region components being outside a frequency band of the reference signal; and a counter means for counting the number of times

Abstract: A ghost canceller for cancelling the ghost with dummy ghost signals opposite in characteristics to the ghost signals. Such dummy ghost signals are generated under control of tap gain controls signals and delay control signals generated by analysis of received TV video signals. The filter control circuit in the ghost canceller comprises a standard signal discriminator for discriminating whether the relationship among the subcarrier signal, and the vertical and horizontal synchronizing signals of the input video signal meets the above-mentioned standards or not; and a zero gain signal generator for otherwise setting the tap gain control signal of the ghost cancelling filter to the corresponding value to zero tap gain.In virtue of this construction, the input of nonstandard TV signal unmeet for the standards results in zero tap gain of the transversal filter, and thus the input signal passes, as unaffected, through the ghost filter, and then outputted.

Abstract: A ghost signal removal apparatus for a broadcasting reception system, includes an analog/digital converter for converting a video signal of a received broadcasting signal into a digital signal. A first filtering circuit is adaptive to a reference signal contained in the digital signal from the analog/digital converter, to remove from the digital signal a ghost signal component appearing at the front of a main video signal. A second filtering circuit is adaptive to a reference signal contained in an output signal from the first filtering circuit, to remove from a fed-back final video signal a ghost signal component appearing at the rear of the main video signal. A subtractor subtracts an output signal from the second filtering circuit from the output signal from the first filtering circuit to obtain the final video signal in which the ghost signal has been removed. A digital/analog converter converts an output signal from the subtractor into an analog signal.

Abstract: A ghost cancelling apparatus and method for quickly and sufficiently cancelling a ghost in a video signal, particularly a spread ghost, include performing a cross-correlation operation between the output video signal and a ghost cancelling reference signal, and correcting a filter coefficient based on the cross-correlation operation result when a remaining ghost is not less than a predetermined value, while when the remaining ghost is less than a certain value, the filter coefficient is corrected according to a least mean square method.

Abstract: A transmission distortion elimination device for eliminating from a transmitted TV signal, for example, signal distortion such as ghost under fuzzy inferenced control based on an iterative correction method with the capabilities of fast control settling, and a flexible and stable distortion removal operation. The device comprises a filter section for suppressing such transmission distortion as ghost, a controller for controlling the tap coefficients of the filter section, and a fuzzy inference section for receiving distortion information obtained by the controller. The fuzzy inference section iteratively infers and evaluates a correction value of tap coefficients of the filter section. The tap coefficient correction value is determined through fuzzy inference, and the control method for counteracting disturbance coefficients to the control system is described in rules of IF-THEN form based on fuzzy levels, which facilitates the organization of the control algorithm.

Abstract: A system for improved ghost cancellation for use in particular in television receivers. The system featuring a superior ghost cancellation reference (GCR) signal which exhibits improved performance in noisy environments and which exhibits the flat and wide bandwidth necessary for effective channel characterization which also exhibiting a higher and more evenly distributed amplitude versus time characteristic than that provided by known, non-cyclic ghost cancellation signals. The GCR signal is encoded a selected television line of an eight field sequence of lines however the polarity of the GCR signal is reversed selectively from field to field prior to inserting it in respective television lines. At a decoder or television receiver incorporating the invention, the selected television lines are combined in a manner which provides for both a robust received GCR value and cancellation of the effects of pair-wise constant television line signals on the GCR signals.