Abstract: A signal processing arrangement has a signal source for providing an information bearing RF signal, a signal output point, and a control circuit coupled between the signal source and the signal output point for controlling the selection of a low noise figure amplifier including impedance matching circuitry or an attenuator in response to the quality of the information borne by the RF signal.

Abstract: A display device that is capable of displaying either one of a video signal whose aspect ratio coincides with that of a display screen and a video signal whose aspect ratio differs includes a boundary-position detector 5 for detecting a boundary position between a signal of a picture portion of the video signal whose aspect ratio differs and a signal of a non-picture portion on the basis of the video signal and a synchronizing signal which are inputted to the boundary-position detector 5, a masking-control-signal generator 15 for generating a masking control signal for masking the non-picture portion and an end portion of the picture, and a masking section 6 for replacing the signals of the non-picture portion and the end of the picture portion with a predetermined substitute video.

Abstract: In accordance with one embodiment of the invention a spread spectrum pixel clock signal is generated to spread out the frequency bandwidth within which the peak emission of an electromagnetic interference signal occurs, so as to decrease the peak electromagnetic emission level. In one embodiment of the invention, this objective is accomplished by employing the horizontal synchronization signal of a video image to generate a periodic waveform that modulates the pixel clock reference input, such that clock signal pulses are spread out within each scan line. The modulation signal is synchronized with the horizontal synchronization signal such that each pixel location remains consistent in the horizontal and time domain.

Abstract: Disclosed is a channel equalizing apparatus and method for a digital television receiver that performs channel equalization using equalizing algorithms. The channel equalizing apparatus includes a channel equalizing section for compensating for channel distortion using a blind algorithm and a decision directed algorithm among equalizing algorithms, and a equalizing control section for calculating error values for compensating for the channel distortion from the blind algorithm and the decision directed algorithm and controlling the channel equalizing section to compensate for the channel distortion according to the calculated error values.

Abstract: A translator demodulates a received digital television signal so as to produce a digital data stream, a symbol clock, and a byte clock, wherein the symbol clock and the byte clock are corrupted by phase noise. The digital data stream is written into a buffer in response to the corrupted byte clock. The corrupted symbol clock is applied to a frequency/phase locked loop having a narrowband loop filter. The frequency/phase locked loop produces a regenerated symbol clock having substantially no phase noise. The digital data stream is read from the buffer in response to the regenerated symbol clock. The digital data stream read from the buffer and the regenerated symbol clock are applied to a modulator for re-broadcasting of the received digital television signal.

Abstract: In a radio receiver for digital television signals a digital filter supplies the in-phase synchrodyning circuitry a shaped spectral response to the digitized I-F signal. The amplitude-versus-frequency response of the digital filter rolls off through the carrier region, so that there is substantially no boost of the amplitudes of lower frequency components of the baseband symbol coding recovered by the in-phase synchrodyning circuitry, with respect to the amplitudes of higher frequency components of the baseband symbol coding such circuitry recovers. When the DTV receiver is initially tuned to a channel, the adaptation of the adaptive channel equalizer proceeds without having initially to compensate for the low-end boost.

Abstract: A method and apparatus for compensating for time base or phase errors in video and audio signals that are separately stored or processed. A ring oscillator provides a plurality of clock signals, each having a same frequency and slightly different phase. Each of the clock signals is applied to a multiplexor for allowing an appropriate one of the clock signals to be selected. By selecting appropriate ones of the clock signals in a sequence, the frequency and phase of an output clock signal formed by the multiplexor can be continuously and precisely controlled. Sync pulses separated from a video signal having a varying time base are applied to a video timing generator circuit which generates a series of digital values representative of timing differences between an expected occurrence of a sync pulse and an actual occurrence of the sync pulse. A phase accumulator accumulates the digital values over time for generating appropriate addresses for the multiplexor.

Abstract: At transmission of a digital modulated wave between a digital set top box and a digital TV, favorable transmission with little picture quality deterioration and noise is realized without employing a coaxial cable.

Abstract: A video data transmitting method fortransmittin a video data from a transmitter to a receiver comprises the steps of dividing one screenful of video data into specified rectangular areas, generating at least two types of video data (first and second video data) each having different resolution from video data existing in the rectangular areas, and transmitting the two types of video data as one video data (video data for transmission).

Abstract: An NTSC co-channel interference detector (44) detects the presence of an interfering NTSC signal in the received Q-channel signal that is orthogonal to the received I-channel signal, rather than detecting the presence of an interfering NTSC signal in the received I-channel signal. By determining whether or not a significant amount of NTSC co-channel interference accompanies the received Q-channel signal, it is inferentially determined whether or not a significant amount of NTSC co-channel interference accompanies the received I-channel signal, such as to cause too many errors in the trellis decoding of equalized received I-channel signal to be corrected by the Reed-Solomon decoder (40) following the trellis decoder (34). The accurate determination of co-channel NTSC interference levels is simplified, because essentially no direct bias arises from the quadrature-phase synchronous detection of the pilot carrier of the VSB AM digital television signal.

Abstract: An apparatus for judging if a co-channel interference exists in a digital TV receiver is disclosed. The TV receiver includes a comb filter for removing NTSC interference of input data, and a selector for selectively outputting data which passed through the comb filter or data which did not pass through the comb filter according to a selection signal. The apparatus includes a gain controller for controlling the gain of noise which did not pass through the comb filter to change the point of time for turning on/off the comb filter, thereby optimizing the performance of the TV receiver for the channel noise and NTSC co-channel interference.

Abstract: In a device for reducing noise in image signals, the image signals passing through a temporal recursive filter whose feedback factor is a function of movement in the images represented by the image signals, in order to form the feedback factor for the respective current image, a first and a second factor are combined in such a way that the smaller one of the factors substantially determines the feedback factor. The first factor is formed from the feedback factor of the preceding image, and the second factor is calculated from the difference between the preceding image and the current image.

Abstract: In a system for receiving a signal containing digital data representing HDTV image information in the form of multilevel symbols formatted into groups of successive fields, each field comprising a field segment, a plurality of data segments, and associated sync components, the received signal is demodulated to produce a demodulated signal. The demodulated signal is comb-filtered to reject NTSC co-channel interference to produce a filtered signal. The filtered signal is trellis decoded with a trellis decoder employing a truncated non-Euclidean metric.

Abstract: A digital television receiver converts very-high-frequency intermediate-frequency digital television signal to a band with uppermost frequency in the lower portion of the high-frequency range. This facilitates RLC analog filtering, such as a Butterworth-Thomson-transition filter or a bridged-T trap filter, being used for suppressing the frequency-modulated audio carrier of co-channel NTSC analog television signal prior to the digital television signal being synchrodyned to baseband for recovering symbol code. The delay distortion introduced by this analog filtering is compensated for in substantial part in surface-acoustic-wave bandpass filtering of the very-high-frequency intermediate-frequency digital television signals. Remnant delay distortion is reduced by channel equalization filtering carried out in the digital regime.

Abstract: A system and method for the on-demand transcoding of media content from a source type to a destination type is provided, wherein the system includes a plurality of transcoders for transcoding from a plurality of source types to a plurality of destination types, and wherein the system receives a transcoding request for media content, fetches the media content in response to the transcoding request, sends the media content to one of the plurality of transcoders based on the source type and destination type, transcodes the media content from the source type to the destination type, thereby generating transcoded media content, and transmits the transcoded media content. The system fetches, sends, and transcodes the media content and transmits the transcoded media content in a pipelined fashion. The system also provides for the publication of media content as a file or stream of digital data, for the archiving of media content, and the caching of transcoded media content to improve system efficiency.

Abstract: There is disclosed a system and method for recovering a recurring data segment synchronization pattern in the presence of an arbitrary phase rotation of a pilot carrier by detecting and compensating for the amount of the phase rotation. The system comprises a first synchronization pattern detector capable of receiving a real component of a complex signal and detecting a data segment synchronization pattern on the real component, and a second synchronization pattern detector capable of receiving an imaginary component of a complex signal and detecting a data segment synchronization pattern on the imaginary component. There is also disclosed a method for compensating a pilot carrier phase rotation comprising the steps of determining the angle of pilot carrier phase rotation present in a complex signal and rotating the pilot carrier signal through the same angle in the opposite direction.

Abstract: A modulation/demodulation receiver having a reference signal in a digital communication system. A method for signal processing and co-channel interference signal removal in the receiver includes the steps of processing an input signal to be at a predetermined multilevel, feeding the processed signal to an adaptive equalizer, determining the type of multilevel from the signal applied to the adaptive equalizer and selecting an operation mode from at least two multilevel operation modes, for the adaptive equalizer and blocks downstream from the adaptive equalizer, and causing the adaptive equalizer to adaptively equalize the signal at the predetermined multilevel in the selected operation mode and remove co-channel interference.

Abstract: Interference and/or nonlinear distortions are reduced in a signal communicated from a transmitter to a receiver. To reduce interference, the transmitter is momentarily disrupted, during which time the receiver analyzes interference on the communication path to determine the frequency of at least one peak thereof. Information is communicated from the receiver to the transmitter identifying the frequencies of the interference peaks. Based on this information, the transmitter pre-distorts the signal to accentuate the signal magnitude at the identified frequencies. The pre-distorted signal is then communicated to the receiver, where it is filtered to attenuate the signal magnitude at the identified frequencies. An adaptive scheme periodically determines the interference peak frequencies. For nonlinear distortion cancellation (e.g., CSO/CTB), there is no need to disrupt the transmitter since the frequencies of the distortion are already known.

Abstract: A method and system for maintaining the quality of video transported over wireless channels uses a transcoder to modify and maintain the optical resilience of an encoded bitstream. The transcoder increases the spatial resilience by reducing the number of blocks per slice, and increases the temporal resilience by increasing the proportion of I-blocks that are transmitted in each frame. Also, the transcoder maintains the same input bit rate by dropping less significant coefficients as it increases resilience. The transcoder of the present invention maintains the resilience at an optimal level to accommodate the prevailing channel conditions as measured by the BER of the wireless channel. Rate distortion theory is applied to determine the optimal allocation of bit rate among spatial resilience, temporal resilience and source rate, where it is has been found that the optimal allocation of the present invention (which occurs in near-real time) provides nearly the same result as doing an exhaustive search.

Abstract: A transmission system (14) broadcasts an information signal. Within the system (14), several components (e.g., 20-24) cause distortion to the information signal as the signal is processed and proceeds toward a broadcast antenna. Specifically, the group of distortion causing components (20-24) is identified as a first group, and is arranged in a sequence along a signal path (12) toward the antenna. The first group of components (20-24) performs various functions, including amplification, but each subjects the information signal to distortion shifts away from intended values. A second group of components (e.g., 28-32) modifies the information signal to compensate for the distortion shifts imposed by the first group of components (20-24). The second group of components (28-32) is located upstream of the first group of components (20-24).

Abstract: A system and method for transmitting advanced television signals such as digital television signals. The system and method controls the frequency of the RF signal by compensating for errors in the signal received from a transport system. The system and method also reduces the complexity of the transmission system by inserting a pilot frequency signal after the television signal has been filtered and shaped.

Abstract: A radio receiver uses the same tuner for receiving a selected digital television (DTV) signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal. The tuner supplies a final IF signal in a 6-MHz-wide frequency band, the lowest frequency of which is not appreciably more than 2.69 MHz. The final IF signal is digitized at a rate that is a multiple of both the symbol frequencies of the QAM and VSB signals, for synchrodyning to baseband, with the 2.69 MHz difference between the carrier frequencies of QAM and VSB signals being taken into account in the digital synchrodyning circuitry. The carrier frequencies of the QAM and VSB final IF signals are regulated to be submultiples of the multiple of both the symbol frequencies of the QAM and VSB signals by applying automatic frequency and phase control signals developed in the digital circuitry to a local oscillator of the tuner.

Abstract: An adaptive apparatus (10) for compensating a linear distorting action to an information signal within a non-ideal transmission system (12). Within the system (12), an information signal proceeds to a transmitter (34) that has an amplifier (62). A sample signal is coupled-off from the transmitter (34). The linear distorting action of the system (12) includes shifting of at least one aspect of the signal away from its intended value. A linear pre-equalizer (54), located along a signal stream of the information signal to the transmitter (34), pre-equalizes the information signal. An adaptive equalization determination (70), connected to receive the sample signal and the information signal outside of the signal stream to the transmitter (34), determines an amount of pre-equalization required from the linear pre-equalizer (54) to compensate the linear distorting action of the system (12).

Abstract: A transmission system (14) broadcasts a signal. Within the system (14), a power amplifier (20) causes non-linear distortion. A pre-amp component, such as a band-pass filter (32), causes linear distortion. A high power filter (38) is located downstream of the power amplifier (20) and causes linear distortion. A linear equalizer (42) compensates for the distortion caused by the high power filter (38). A non-linear corrector (44) compensates for the distortion caused by the power amplifier (20), and is located downstream of the linear equalizer (42). A linear equalizer (46) compensates for the distortion caused by the pre-amp components (e.g., 32). The compensating components (42-46) are located upstream of the distorting, pre-amp component (e.g., 32). Signal sampling points (70-74) are located downstream of each distorting component (20, 32, and 38). Sampling selectively occurs at one of the sample points (70-74) for use to update compensation.

Abstract: A system and method for controlling the frequency of a signal being transmitted wherein the frequency of the signal received at the transmitter site is error corrected before being broadcast. The error in the frequency may be developed and applied to the intermediate frequency upconversion and/or the channel upconversion to reduce or eliminate the effects of the error. In the system and method, a pilot frequency signal can be added to the signal to be broadcast after the signal to be broadcast has been shaped and filtered.

Abstract: A circuit for developing correction signals for on-line controlling a precorrection arrangement in an HDTV 8VSB digital signal transmitter. The transmitted signal is sampled, sorted, smoothed and sliced to determine the symbol amplitude levels of the transmitted multilevel symbols. The centers of the sliced clusters of sampled symbol levels are used to determine the symbol amplitude levels. Correction signals for compensating the precorrection arrangement are developed based upon the determined symbol levels and the known symbol levels.

Abstract: For a method of encoding digital data of arbitrary data rates of at least one data signal for jointly transmitting the encoded data with a digital picture signal, as well as a data encoder for such data, a flexible adaptation to different data formats is provided in which, in the encoding of data, at least parts of the edges of data bits of the data signal are replaced by synthetically generated amplitude values constitutes edges which are within the bandwidth limitations predetermined for the encoded data bits.

Abstract: A partial fractionally spaced equalizer for a digital television includes, a feedforward filter unit for receiving an input signal sampled at a predetermined frequency, which is divided a first region having a symbol spaced tap and a second region having fractional spaced taps narrower than the symbol spaced tap, a feedback filter unit having symbol spaced taps, a equalizer signal generator for processing feedforward tap signals outputted from the feedforward filter unit and the feedback tap signals outputted from the feedback filter unit and generating equalizer signals, a slicer for slicing the equalizer signals to generate a decision data and outputting the decision data to the feedback filter unit, and an error generator for generating a compensating error signal by subtracting the equalizer signal from the decision data. When a sampled input signal (Si) of 21.

Abstract: The present invention relates to a digital television relay system for relaying wirelessly a broadcasting signal discharged from a broadcasting station. In order to cover shadow areas of the digital broadcasting channel signal discharged from a digital television transmitter, the present invention receives the broadcasting channel signal of a certain frequency discharged from the broadcasting station, performs channel-decoding, compensates a transmission error occurred in space, and relays it wirelessly to a subscriber in the shadow areas. Accordingly, the present invention can provide a digital television broadcasting service with transmission quality same with the broadcasting station to the subscriber in the shadow areas.

Abstract: An ATV receiver is provided with a 16-state trellis decoder to achieve improved performance in the presence of NTSC co-channel interference. In one embodiment, the ATV receiver comprises a tuner, a comb filter, and a trellis decoder. The tuner is configured to downmix a selected channel frequency signal to an intermediate frequency signal, where the comb filter is configurable to screen out most of the NTSC co-channel interference. The intermediate frequency receive signal is modified by the comb filter to resemble a partial response signal. The trellis decoder the demodulates the partial response signal in an improved fashion taking into account the state of the trellis encoder and the partial response channel. The trellis decoder may have a 16 state trellis comprised of four 4-state butterflies wherein each edge in the trellis is a single transition.

Abstract: A first comb filter differentially combines an I- or Q-channel baseband signal supplied as input signal to a co-channel NTSC interference detector for a DTV receiver with that signal as subjected to a first amount of differential delay. This generates a first comb filter response in which artifacts arising from synchronous detection of the co-channel interfering analog television signal are suppressed. The detector includes a second comb filter that combines the input signal with that signal as subjected to a second amount of differential delay to generate a second comb filter response in which artifacts of the co-channel interference are reinforced. The first and second comb filters both use the same type of linear combiner so the direct term of input signal is treated similarly in the first comb filter response and in the second comb filter response. First and second amplitude detectors detect the respective amplitudes of these comb filter responses.

Abstract: A system for reducing bandwidth of video signals. Ordinarily, an NTSC (National Television Standards Committee) video signal has (a) a bandwidth of 6.0 MHz, (b) chrominance and luminance carriers separated by about 3.58 MHz, and (c) an audio carrier located at the upper end of the 6.0 MHz bandwidth. The invention reduces the separation between chrominance and luminance carriers to about 2.15 MHz, and decreases the bandwidth to about 4.0 MHz. In addition, the invention moves the audio carrier outside the 4.0-MHz bandwidth. The invention allows multiple channels, of 4.0 MHz bandwidth each, to be placed adjacent each other in a cable television spectrum, and the audio signals of the channels to be placed together, at the upper end of the spectrum, outside the range allocated to the video information. A larger number of channels is obtained than would otherwise be available, because the upper end of the spectrum is not suitable for carrying video information, but will handle audio information.

Abstract: A television signal receiver for processing an HDTV signal transmitted in a vestigial sideband (VSB) format includes input complex filters shared by a timing recovery network (30) and a carrier recovery network (50). The filter network includes a pair of upper and lower band edge filters (20, 22) mirror imaged around the upper and lower band edges of the VSB signal for producing suppressed subcarrier AM output signals. The timing recovery network includes a phase detector (28, 38, 62) and responds to an AM signal derived from the two filters (via 26) for synchronizing a system clock (CLK). The carrier recovery network (50) also includes a phase detector (54, 60, 62, 64), and responds to outputs from one or both of the filters for producing an output error signal (.DELTA.) representing a phase/frequency offset of the VSB signal. The error signal is used to reduce or eliminate the offset to produce a recovered baseband or near baseband signal.

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 method and apparatus for transmitting and receiving frequency hopped video signals is disclosed. A composite video signal is processed at a transmission end to remove line and frame synchronization codes and replace them with a frequency hopping synchronization code. The signal is then modulated with a frequency hopped carrier signal and transmitted to a receiver. The receiver detects the frequency hopping synchronization code to enable tuning of the receiver to the video signal. The detected frequency hopping synchronization codes are removed and replaced with the original line and frame synchronization code. The recreated video signal may be digitized and processed to detect and correct errors within the video signal by replacing lines or frames of the video signal with closely related lines or frames from another portion of the video signal.

Abstract: Program specific information (PSI) is formed suitable for use in recovering data content of a program in the form of a packetized datastream. Packet identifiers (PIDs) that identify individual packetized datastreams constituting the program are renumbered and corresponding packetized datastreams that constitute different programs are given the same PID. A program map table (PMT) is created that associates the renumbered PIDs with the individual packetized datastreams constituting the program. A program association table (PAT) is also created for associating the program with PIDs that identify packets comprising the PMT. A parameter may be employed within the PSI to indicate that the PSI is to be applied in subsequent processing of the program irrespective of a substantive difference between the PSI and previous PSI content. In addition, the PSI may incorporate a version number that is varied between successive occurrences of the PSI irrespective of substantive change in PSI content.

Abstract: A VSB mode detection circuit with a comb filter solves the potential problem of lockout in a situation where an 8 VSB mode signal is being received, with the comb filter being effective, and a change in signal mode suddenly occurs. The arrangement inhibits the first two bytes of the three byte mode information, which two bytes are unspecified for all except the 8 VSB terrestrial mode, and replaces them with zero data. In another embodiment, the 12 symbol delay in the comb filter is bypassed with the complement of the input data for the third byte. When the 8 VSB terrestrial mode has been confidently determined to exist, the inhibition of the first and second bytes (and the inversion of the bypassed third byte) is removed in alternate fields to permit normal comb filter operation.

Abstract: By selecting the number of apertures per vertical row in the shadow mask of a color cathode ray tube to be in the range between 615 and 650, such a cathode ray tube can be used both in a PAL, an NTSC system and a MUSE system without the occurrence of disturbing Moire effects. In a second embodiment the number of apertures per row ranges between 425 and 450.

Abstract: A digital television receiver operating in the presence of an NTSC co-channel signal includes an NTSC rejection filter that is selectively inserted in the digital television signal path to minimize interference from the NTSC co-channel signal. The energy around the NTSC picture carrier is sampled. This is compared with sampled white noise energy between the NTSC picture and color carriers, after field combing the digital television signal to eliminate the effects of static signals. The comparison is used to determine whether or not the NTSC rejection filter is inserted in the digital television signal path.

Abstract: When both an NTSC signal and an ATV signal are concurrently broadcast in a co-channel, it is desirable to remove the NTSC signal at the receiver when reproducing the broadcast ATV signal, since the NTSC signal would interfere with the ATV signal. An NTSC rejection filter is used to remove most of the signal power of an NTSC broadcast signal. To more effectively handle multipath interference signals, the present invention adaptively controls the driving selection of an NTSC rejection filter. The mean power levels are calculated for an input signal which has not been NTSC rejection filtered and for a second input signal which has been NTSC rejection filtered. Error differences are then calculated for each of these mean power levels and a driving selection is determined for the NTSC rejection filter based upon the calculated error differences.

Abstract: An image-processor system for compensating for accumulated phase-and-gain errors incurred during transmission of a video signal over a communications channel. The image-processor system comprises an initial-video processor, an input-video processor, a feature-video processor, a frame buffer, an RGB-output processor, an output-video processor, and a control processor. The initial-video processor generates a composite video signal. The input-video processor converts the composite video signal into digital-component signal information. The feature-video processor processes the digital-component signal information as processed component video information. The frame buffer re-establishes broadcast timing standards in the processed component video information to generate time-base corrected digital information. The RGB-output processor decodes the time-base corrected digital information into RGB analog and digital outputs. The analog RGB outputs are output directly.

Abstract: Co-channel interference accompanying multiple-level symbols in a digital receiver, such as a digital television receiver, is suppressed by using a first comb filter to reduce the energy of the co-channel interference before data slicing. The first comb filter incidentally carries out a symbol re-coding procedure of first type that introduces error into the symbol decoding results generated by the data slicing. A second comb filter carries out a symbol re-coding procedure of second type after the data slicing to compensate for the symbol re-coding procedure of first type and generate corrected symbol decoding results. The symbol re-coding procedure of first type re-codes an input symbol stream through differential delay and first linear combination of the differentially delayed terms.

Abstract: A transmitted digital VSB signal comprises a sequence of M-level symbols, where the value of M is defined by a mode control signal which is periodically multiplexed with the transmitted signal. A receiver includes an up/down counter which is reset to a zero count in response to a channel change signal and a latch responsive to the zero count of the counter for storing the next received mode control signal whose accuracy has been verified. The counter is incremented or decremented in response to each subsequently received verified mode control signal which respectively matches or does not match the stored mode control signal. Acquisition of new mode control signals is thereby relatively immune to burst noise, is effected very rapidly after a channel change and less rapidly in the absence of a channel change.

Abstract: A frequency processing circuit has a suppressing circuit for suppressing a lower sideband wave of an input FM signal whose frequency is modulated, a frequency conversion circuit for converting the frequency of an output of the suppressing circuit, and an emphasizing circuit for emphasizing a lower sideband wave of an output of the frequency conversion circuit. The emphasizing circuit emphasizes a share of the amount of the wave suppressed by the suppressing circuit.

Abstract: A television signal receiver for processing an HDTV signal transmitted in a vestigial sideband (VSB) format with a one-dimensional data constellation includes a first carrier recovery network (18), an equalizer (20), and a second carrier recovery network (22, 30, 62). A multiple stage quantizer network (50, 66) exhibiting progressively finer resolution is associated with the operation of the equalizer for providing blind equalization without need of a "training" signal. The second carrier recovery network includes a phase detector (30) wherein a one-symbol delayed (312) input signal and a quantized (310) input signal are multiplied (316), and an unquantized input signal and a quantized (310) one-symbol delayed (314) input signal are multiplied (316), and an unquantized input signal and a quantized (310) one-symbol delayed (314) input signal are multiplied (318). Signals produced by the multiplication are subtractively combined (320) to produce an output signal representing carrier phase error.

Abstract: A VCR or laserdisc player includes circuitry for detecting a code provided by VCR tapes, tape cassettes, or laser videodiscs, which indicates that the material recorded on the videotape or videodisc has been recorded in a compressed fashion to enable proper playback on a 16.times.9 television receiver. In response to detection of this code, the VCR or laserdisc player applies a DC signal to the chrominance output terminal of its S-Video connector. Circuitry in the television receiver detects the DC signal on the chrominance terminal of its S-Video input connector, and controls a wide-screen processor to expand the image by displaying it over the entire width of the 16.times.9 display screen.

Abstract: A digital advanced television (ATV) receiver includes a multi-tap feedforward filter for reducing NTSC co-channel interference in a received ATV signal. A complementary Tomlinson precoder is used to compensate the transmitted ATV signal for inter-symbol interference (ISI) created in the receiver by the feedforward NTSC rejection filter. Data components of the transmitted signal are non-linearly precoded while synchronization components are linearly precoded to improve sync recovery S/N performance in the receiver.

Abstract: A receiver receives an ATV (e.g. HDTV) signal in an area that is subject to NTSC co-channel and other interference. The received signal is precoded at the transmitter for enabling reduction of NTSC co-channel interference in the received signal. The received signal includes field sync signals that are successively field combed to produce a subtraction signal. The subtraction signal is comb filtered to reduce NTSC co-channel interference and applied to a comparator along with the unfiltered subtraction signal. The comparator determines whether the level of NTSC co-channel interference is sufficiently great to subject the received ATV signal to comb filtering for reducing the NTSC co-channel interference.

Abstract: A technique for enhancing the robustness of an ATV transmission system in the presence of NTSC or ATV co-channel interference comprises positioning the ATV signal relative to the co-channel NTSC/ATV signal to reduce interference into the ATV receiver. In a preferred embodiment, the ATV signal is positioned relative to a co-channel NTSC signal such that the demodulated difference f.sub.v -f.sub.p in the ATV receiver is equal to 70.5 f.sub.seg, where f.sub.v is the NTSC visual carrier frequency, f.sub.p is the ATV pilot carrier frequency and f.sub.seg is the ATV segment repetition rate, and relative to a co-channel ATV signal such that their respective pilot frequencies differ by an amount equal to 1.5 f.sub.seg.

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.