Abstract: In one embodiment, an apparatus includes: a digital-to-analog converter (DAC) circuit having a digital portion to receive a digital value and an analog portion to generate an analog voltage based on the digital value; and a refresh circuit coupled to the DAC circuit to clock gate provision of a first clock signal to the DAC circuit when the digital portion is inactive.

Abstract: An image sensor has an array of pixels configured in multiple blocks; each block coupled to a separate analog-to-digital converter (ADC) to provide digitized image data. The ADCs feed digitized images into an image RAM; and the image RAM feeds digitized images to an alignment buffer in a first pixel order. The alignment buffer provides digitized images to an image processor in a second pixel order different from the first pixel order. In an embodiment, the alignment buffer uses a multiport RAM. In another embodiment, the alignment buffer uses first and second alignment buffer RAMs, writing one alignment buffer RAM while reading the other alignment buffer RAM to provide image data to the image processor. In embodiments, the alignment buffer provides digitized images in an order selectable between a full resolution and a reduced resolution order, and selectable between a right-to-left and left-to-right order.

Abstract: Receiver and method for receiving one or more RF signals, the RF signals comprising a component relative to a direct propagation path and, depending on a propagation environment, one or more additional components relative to reflected propagation paths, the receiver comprising a calculation circuit configured to: compute at least a first correlation function (310) between the received signal and at least a replica of a RF signal generated at the receiver, and for at least an output of said first correlation function: perform a cepstrum transform (410), search for one or more reflected propagation paths from the output of the cepstrum transform (411), and when reflected propagation paths are detected, determine the associated propagation characteristics (412), and remove the contribution of the detected reflected propagation paths from one of the received signal or the output of the first correlation function.

Abstract: A color space converter converts data points from one color space to another color space using a lookup table. Color space converters may be used in any device that involves image processing, such as displays and printers. An interface receives an input value in a first color space. A controller access a lookup table stored in memory to determine an upper bound and a lower bound of a subset of the color space. An output value is interpolated between the upper bound and the lower bound using interpolation values. The interpolation values of the last subset in any dimension of the color space are modified by a scale factor to approximate ideal values.

Abstract: A band processing circuit which generates image signals corresponding to different frequency bands from an image signal in which signals corresponding to different colors are arranged and which suppresses noise by synthesizing the image signals of the different frequency bands, a sampling circuit which generates image signal corresponding to the colors by sampling the image signal input from the band processing circuit in accordance with a predetermined arrangement, and a luminance/color generation circuit which generates a luminance signal in which aliasing is suppressed using an image signal output from the sampling circuit.

Abstract: A color space converter converts data points from one color space to another color space using a lookup table. Color space converters may be used in any device that involves image processing, such as displays and printers. An interface receives an input value in a first color space. A controller access a lookup table stored in memory to determine an upper bound and a lower bound of a subset of the color space. An output value is interpolated between the upper bound and the lower bound using interpolation values. The interpolation values of the last subset in any dimension of the color space are modified by a scale factor to approximate ideal values.

Abstract: Digital television broadcasting signals employ parallel concatenated convolutional coding, commonly called “turbo coding”, to improve reception by receivers in motor vehicles. Turbo coded Reed-Solomon codewords are transversally disposed in the payload fields of encapsulating MPEG-2-compliant packets to improve the capability of the Reed-Solomon coding to overcome deep fades. Turbo codewords are transmitted more than once in so-called “staggercasting”. Reception of DTV signals is improved by combining soft decisions concerning repeated transmissions of turbo codewords before turbo decoding. Only the data components of turbo codewords are transmitted twice in “punctured” staggercasting of turbo codewords, with parity components being transmitted only once, so code rate is reduced by a smaller factor than two.

Abstract: A method of processing broadcast data in a transmitting system includes randomizing enhanced data; Reed-Solomon (RS) encoding and Cyclic Redundancy Check encoding the randomized enhanced data to build an RS frame; encoding the enhanced data in the built RS frame at a coding rate of at least ½ or ¼; first interleaving the encoded enhanced data; deinterleaving the first interleaved enhanced data; first multiplexing enhanced data packets including the deinterleaved enhanced data with main data packets including main data; randomizing the main data in the multiplexed enhanced and main data packets; second interleaving the enhanced data in the multiplexed enhanced and main data packets and the randomized main data to output a data group having the interleaved enhanced data and the interleaved main data; trellis encoding data in the data group in a trellis encoding unit; and second multiplexing the trellis-encoded data with field synchronization data and segment synchronization data.

Abstract: A method of processing a digital broadcast signal includes Reed-Solomon (RS) encoding enhanced service data for each column of at least one RS frame payload and adding a Cyclic Redundancy Check (CRC) checksum byte at a right end of each row of the at least one RS frame payload to build at least one RS frame and forming data groups including the enhanced service data in the built RS frame and a plurality of known data sequences. Forming the data groups includes mapping the RS encoded enhanced service data into each of the data groups and inserting a place holder for a non-systematic RS parity into each of the data groups. The method further includes deinterleaving data in each of the data groups including the enhanced service data and the place holder and multiplexing the enhanced service data in each of the formed data groups with main service data.

Abstract: Digital television broadcasting signals employ parallel concatenated convolutional coding, commonly called “turbo coding”, to improve reception by receivers in motor vehicles. Turbo coded Reed-Solomon codewords are transversally disposed in the payload fields of encapsulating MPEG-2-compliant packets to improve the capability of the Reed-Solomon coding to overcome deep fades. Turbo codewords are transmitted more than once in so-called “staggercasting”. Reception of DTV signals is improved by combining soft decisions concerning repeated transmissions of turbo codewords before turbo decoding. Only the data components of turbo codewords are transmitted twice in “punctured” staggercasting of turbo codewords, with parity components being transmitted only once, so code rate is reduced by a smaller factor than two.

Abstract: A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

Abstract: A method and apparatus for computing a convolution between a satellite signal from one of a plurality of satellite positioning systems and a pseudorandom code reference. The method and apparatus is capable of operating in multiple modes of resolution so as to enhance the sensitivity of the convolution processing.

Abstract: A device comprising a circuit for picking up acoustic signals with the microphone; a circuit for playing back audio signals with an amplifier and a loudspeaker; an interface circuit for interfacing with a telephone network or a cell phone; and a circuit for digitally processing audio signals and reducing the acoustic echo that results from interaction of the loudspeaker with the microphone. The circuit for digitally processing audio signals comprises: an echo cancellation stage with an adaptive linear filter suitable for subtracting from the signal picked up by the microphone a reference signal that is derived from the signal received at the output from the interface; a gain control stage for suppressing the residual echo, and a stage for selectively reducing the background noise present in the signal received at the output from the echo suppression stage.

Abstract: The device comprises a microphone for detecting a speech signal from a near speaker, and a loudspeaker for reproducing a speech signal from a remote speaker. The processing for canceling the interfering acoustic echo implements an adaptive linear filtering algorithm. Double talk situations are detected by: evaluating an index representative of the convergence or divergence of the algorithm; assessing a predetermined condition for detecting a double talk situation; and if the condition is satisfied, modifying at least one parameter of the algorithm in response to the detection. The representative index may be the norm of the gradient vector describing the adaptation of the filter from one iteration of the algorithm to the next, the conditions being a comparison between the gradient and a threshold. The parameter that is modified double talk situation may be the adaptation stepsize of the algorithm, and also the gain control of an echo suppression stage.

Abstract: This invention relates to a method, a computer program, a computer program product and a device for reducing motion blur of images shown on non-stroboscopic display devices, in which local areas p, of an image of a video signal are displayed during respective local display times t; that are less than or equal to a image period T, comprising determining (40) an amount X; of high spatial frequency content related to a local area p, of said image of said video signal, and adjusting (41) a local display time t, in dependence on said determined amount X; of high spatial frequency content, wherein said local display time t; is decreased with increasing determined amount X; of high spatial frequency content.

Abstract: A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

Abstract: A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

Abstract: The present invention is applied, for example, to resolution conversion. An edge gradient direction v1 with the largest gradient of pixel values and an edge direction v2 orthogonal to the edge gradient direction v1 are detected. Edge enhancement and smoothing processing are performed in the edge gradient direction v1 and in the edge direction v2, respectively, to generate output image data D2.

Abstract: Disclosed is a ghost cancellation system based on an enhanced ghost cancellation reference signal for noisy environments. The received analog television signal is first subjected to a digitization step for processing in the digital domain. A wavelet de-noising operation is applied on the reference signal to remove undesired noises before a communication channel is estimated, and filter coefficients are optimally determined. The digitized composite signals are then ghost-reduced by IIR and FIR filters. The power consumption and training time of the realized chip are decreased, which is ideal for mobile and platform applications.

Abstract: A novel echo cancellation reference (“ECR”) training signal is inserted into the current ATSC 8 VSB data stream to achieve improved echo rejection while maintaining compatibility with the ATSC 8 VSB digital ATV standard. The novel ECR training signal is also suitable for other multipath or dispersive digital communication channels. A pre-equalization subsystem is included in the digital ATV system as a front end to the VSB receiver, and is trained with preferably the novel ECR training signal. One type of pre-equalization subsystem provides a fully ATSC compliant signal at its output, and therefore is particularly useful with standard VSB receivers. Another type of pre-equalization system provides a signal at its output which is ATSC compliant in some respects but which retains the ECR signal, and therefore is particularly useful for signal relays, analysis purposes, and other applications in which the residual channel information is important.

Abstract: Broadcast DTV signals are improved by including in each of their successive data fields a training signal for the adaptive channel-equalization and echo-cancellation filtering in receivers. The training signal in each data field includes a prescribed number of cycles of a particular pseudo-random noise sequence extending over a plurality of data segments to provide a training signal for the adaptive filtering that is of longer duration than one of said data segments. Each data segment in each data field begins with a data segment synchronizing sequence, and the training signals incorporate some of these data segment synchronizing sequences within themselves. Receivers are described that initialize the parameters of the adaptive filtering using discrete Fourier transform calculations on the training signal, and receivers are described that initialize the parameters of the adaptive filtering using the results of match filtering for the particular pseudo-random noise sequence.

Abstract: A novel echo cancellation reference (“ECR”) training signal is inserted into the current ATSC 8 VSB data stream to achieve improved echo rejection while maintaining compatibility with the ATSC 8 VSB digital ATV standard. The novel ECR training signal is also suitable for other multipath or dispersive digital communication channels. A pre-equalization subsystem is included in the digital ATV system as a front end to the VSB receiver, and is trained with preferably the novel ECR training signal. One type of pre-equalization subsystem provides a fully ATSC compliant signal at its output, and therefore is particularly useful with standard VSB receivers. Another type of pre-equalization system provides a signal at its output which is ATSC compliant in some respects but which retains the ECR signal, and therefore is particularly useful for signal relays, analysis purposes, and other applications in which the residual channel information is important.

Abstract: DTV signals transmitted over the air with a symbol rate of around 10.76 million samples per second include echo-cancellation reference (ECR) signals each of which includes or essentially consists of a repetitive-PN1023 sequence with baud-rate symbols, which repetitive-PN1023 sequence incorporates a number of consecutive data-segment synchronization signals. Receivers for these DTV signals respond to these ECR signals to generate initial weighting coefficients for adaptive filters used for channel equalization and echo suppression. The initial weighting coefficients are calculated from a cepstrum extracted from the repetitive-PN1023 sequence ECR signal by DFT methods or with a PN1023 auto-correlation match filter.

Abstract: Briefly, in accordance with one embodiment of the invention, a method of reducing flicker in a video image sequence includes the following. Successive video images are temporally filtered. The filter length is adjusted so as to reduce the amount of filtering across temporal discontinuities in the video image sequence. Briefly, in accordance with another embodiment of the invention, a method of reducing flicker in a video image sequence includes the following. Successive video images are temporally filtered. The filter length is dynamically adjusted.

Abstract: A method and a system for improved filtering of display data is disclosed herein. A display system may be used to separately filter display components of the display data based on frequency content of the display components. The display system can include a display data source, a digital image processor, and a display. The display system receives display data from the display data source. The frequency content of a plurality of display components in the display data is determined by the digital image processor. The digital image processor filters the plurality of display components based on the associated frequency content. In at least one embodiment, display components having lower frequency content are filtered to minimize flicker, while display components having higher frequency content are filtered to maximize resolution. The filtered display data is then transmitted to the display.

Abstract: The invention relates to a data processing device for recovering digital data which is received in an analogue transmitted signal. According to the invention, the received signal is digitized and a threshold is determined in a threshold estimator. The interference in the channel is corrected in a downstream adaptive equalizer, and a bit clock generator produces the correct sampling rate and phase for the data of a line. The threshold estimator is used to determine the mean value of an input signal for each line, and this value is then taken as the optimum decision value for sampling the data bits for this line. By using an adaptive equalizer, it is possible to correct different types of distortion, caused by the transmission channel, without the need for a training signal. The data processing device according to the invention can thus be used universally for all digital additional signals occurring in a television signal, for example.

Abstract: A block-adaptive method of performing equalization on a signal received over a broadcast system, includes providing a set of predetermined symbols that correspond to symbols in a data field synchronization segment of a data field having a plurality of segments wherein a data frame having at least two of these data fields is transmitted over the signal in the broadcast system during a block-time interval, correlating complex samples of the signal with the set of predetermined symbols to extract a corresponding impulse response during the block-time interval, selecting a phase identifying the start of the block-time interval from the correlated complex samples, estimating an equalizer filter using the set of predetermined symbols and an initial data field synchronization segment provided at the start of the block-time interval, updating the equalizer filter using subsequent complex samples of the signal to extract a subsequent impulse response and correlate with a reference segment, wherein the reference segmen

Abstract: The invention relates to a method for transmitting data streams where transmission/reception devices (LTU, NTU) deactivated to a standby state are activated by performing a warm start sequence, with transmission line parameters being determined (S103) using an exchange-end transmission/reception device (LTU) following provision of a subscriber-end transmitted signal, transmission line parameters being determined (S104) using a subscriber-end transmission/reception device (NTU) following provision of an exchange-end transmitted signal, echo cancelation being realigned (S105) using a subscriber-end transmission/reception device (NTU) following provision of a subscriber-end transmitted signal, and/or echo cancelation being realigned (S106) using an exchange-end transmission/reception device (LTU) following provision of an exchange-end transmitted signal.

Abstract: A novel echo cancellation reference (“ECR”) training signal is inserted into the current ATSC 8 VSB data stream to achieve improved echo rejection while maintaining compatibility with the ATSC 8 VSB digital ATV standard. The novel ECR training signal is also suitable for other multipath or dispersive digital communication channels. A pre-equalization subsystem is included in the digital ATV system as a front end to the VSB receiver, and is trained with preferably the novel ECR training signal. One type of pre-equalization subsystem provides a fully ATSC compliant signal at its output, and therefore is particularly useful with standard VSB receivers. Another type of pre-equalization system provides a signal at its output which is ATSC compliant in some respects but which retains the ECR signal, and therefore is particularly useful for signal relays, analysis purposes, and other applications in which the residual channel information is important.

Abstract: The frequency-modulated sound carrier of any co-channel interfering NTSC television signal that accompanies multiple-level symbols in a digital receiver, such as a digital television receiver, is suppressed using a surface-acoustic-wave (SAW) filter in the intermediate-frequency (I-F) amplifier circuitry. This reduces data-slicing errors during symbol decoding and improves bit error rate (BER) during subsequent trellis decoding. When a comb filter is used before data slicing to reduce the energy of co-channel interfering NTSC television signal, the SAW filter in the I-F amplifier circuitry eases the filtering requirements on the comb filter such that only video components of co-channel interfering NTSC television signal need be suppressed.

Abstract: DTV signals transmitted over the air with a symbol rate of around 10.76 million samples per second include echo-cancellation reference (ECR) signals each of which includes or essentially consists of a repetitive-PN1023 sequence with baud-rate symbols, which repetitive-PN1023 sequence incorporates a number of consecutive data-segment synchronization signals. Receivers for these DTV signals respond to these ECR signals to generate initial weighting coefficients for adaptive filters used for channel equalization and echo suppression. The initial weighting coefficients are calculated from a cepstrum extracted from the repetitive-PN1023 sequence ECR signal by DFT methods or with a PN1023 auto-correlation match filter.

Abstract: In a radio receiver for digital transmissions, an adaptive channel equalizer is clocked at a sampling rate higher than symbol rate by a factor k and employs decision feedback for adjusting the coefficients of its component filters. The channel equalizer response as supplied at the sampling rate k times symbol rate is decimated to symbol rate and quantized to generate a signal estimating the symbols transmitted to the receiver. The channel equalizer response as supplied at the sampling rate k times symbol rate is compared to the signal estimating the transmitted symbols as re-sampled to the sampling rate k times symbol rate, in order to develop decision-feedback error signal at the sampling rate k times symbol rate. This decision-feedback error signal has sufficient digital bandwidth to permit fractionally spaced equalization with all coefficients being optimally adjusted.

Abstract: A mechanism for adaptive selection of anti-ghosting filtering accesses a first plurality of coefficients being used by the anti-ghosting filtering and compares a first set of one or more of the first plurality of coefficients to a first predetermined value. The mechanism then modifies the anti-ghosting filtering based on the results of this comparison. In one embodiment, the mechanism includes both an adaptive baseband equalization filter and a lookup table filter.

Abstract: A method assesses the quality of a television image. In diversity reception installations including several receivers, it is necessary to establish a criterion for selecting the receiver with the best image quality. For this purpose, the five vertical connection impulses are first detected in the video signal. The detection of the five equalization impulses initiates only after the vertical connection impulses have been detected. Then, the detection of the horizontal synchronization impulses, interfering impulses and the echo impulses is carried out only after the equalization impulses have been detected. The number of horizontal synchronization impulses, interfering impulses, and echo impulses detected is used as criterion for selecting the best receiver. The invention is applicable to diversity reception installations including several television receivers, in particular, for mobile installations.

Abstract: A linear filter for use in 8 MHZ television broadcast systems is provided having a frequency response which includes a notch corresponding to a television picture carrier fpix, a notch corresponding to approximately a television color subcarrier fcs, and a notch corresponding to approximately a television sound carrier fs. Accordingly, the linear filter substantially reduces co-channel interference in a digital signal received by a digital television.

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: An apparatus for receiving a television signal containing a ghost cancellation reference signal, and for using the reference signal to process the television signal so as to substantially eliminate path induced distortion.

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 method and apparatus for channel identification utilizing two Least-Squares (LS) estimators. Each LS estimator is used for calculating a sequence of channel values, further for determining an estimated channel impulse response, over an entire frequency band thereof in light of the fact that information is incomplete or unreliable over part of the frequency band. Each LS estimator operates for the case when the estimated channel impulse response span is less than the span of a known test signal, the test signal having been transmitted over the channel for use in identifying the channel. In a TV ghost-cancellation system for removal of channel induced distortion from received signals, each LS estimator is used to compute channel impulse response coefficients, wherein the system includes ghost-cancellation filters responsive to the channel impulse response for removing the effects of the channel from the signals.

Abstract: A television receiver for reducing a co-channel interference in a digital television signal transmitted by a transmitter, wherein the digital television signal includes an encoded digital television signal component, a co-channel interference component, and a noise component, and wherein a precoder, for which precoding is implemented at the television transmitter, encodes the digital television signal. The receiver includes a receiver for receiving the transmitted digital television signal and for providing a received output signal. A filter block is provided for filtering the received output signal to reduce the co-channel interference component thereof. The filter block includes a plurality of rejection filters and a device for enabling a desired one of the plurality of rejection filters in response to a selection control signal, the enabled rejection filter corresponding to an optimal rejection filter for the precoder for which precoding is implemented at the television transmitter.

Abstract: In a ghost cancellation system, it is necessary to synchronize the system to the ghost cancellation reference (GCR) signal contained in the video signal. A free-running oscillation, having a frequency which is the same as that used in generating a reference GCR signal, is used to clock the sampling of the video signal. This assures frequency coherence between the input GCR signal and the stored reference GCR signal. By using cross-correlation, the phase error between the sampled input GCR signal and the stored GCR signal is determined. Based on this phase error, a phase-corrected reference GCR signal is generated and stored. This phase-corrected reference GCR signal is then used in the generation of an error function involving the sampled input GCR signal, the error function being used for eliminating ghosts in the input video signal.

Abstract: A system for improved echo cancellation for use in particular in television receivers. The system features a superior ghost cancellation reference signal which exhibits improved performance in noisy environments and which exhibits the flat and wide bandwidth necessary for effective channel characterization while exhibiting a higher and more evenly distributed amplitude versus time characteristic than that provided by known, non-cyclic ghost cancellation signals.

Abstract: A channel equalizer for a high definition television that enhances the convergent speed of the channel equalizer by renewing first a filter coefficient of a near ghost image and then renewing a filter coefficient of a far ghost image, after distinguishing the filter coefficient corresponding to the near ghost image from the filter coefficient corresponding to the far ghost image.

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 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 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 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.