Abstract: A demodulator (10) converts television signals to video baseband signals and audio baseband signals including stereo signals representing a right channel signal value, a left channel signal value and a pilot signal having an amplitude. A DSP (60) recursively finds a coefficient value for scaling that keeps the pilot signal amplitude within a range of values, there by improving baseband signal quality, such as stereo separation of stereo signals within the baseband signals.

Abstract: A repeater and method for an ATSC terrestrial digital TV broadcasting service.

Abstract: The present invention relates to receivers such as multi-carrier receivers. An orthogonal frequency division multiplex (OFDM) receiver in a terrestrial digital video broadcast (DVB-T) network is required to operate in a complex channel environment, wherein high power analogue television signals may co-exist. The mix of high power analogue television signals and lower power digital signals results primarily from the concurrent existence of both analogue and digital television services. The present invention provides a receiver having improved power efficiency.

Abstract: A digital IF demodulator includes an analog-to-digital (A/D) converter that receives an analog IF signal and converts it to a digital IF signal. A parallel multiplier then down-converts the digital IF signal to a baseband signal having a video component and an audio component. The frequency down-conversion uses a parallel multiplier driven by an outer feedback loop that corrects gross frequency errors in said digital IF signal. The digital IF demodulator also includes a video recovery circuit that selects the video component from the baseband signal and further down-converts the baseband signal to a video baseband using a video complex mixer driven by an inner feedback loop that corrects fast phase perturbations in the video recovery circuit. Finally, the digital IF demodulator includes an audio recovery circuit that (i) receives said baseband signal from the parallel multiplier, and (ii) down-converts the audio component to an audio baseband signal using an audio complex mixer.

Abstract: An adaptive channel equalizer (50) for processing a demodulated VSB signal containing terrestrial broadcast high definition television information includes an adaptive feed forward filter (FFF 20) and an adaptive decision feedback filter (DFF 30). The equalizer is preceded by a demodulator/carrier recovery network (18) and does not include a carrier recovery function in the equalizer control loop. The equalizer FFF and DFF elements operate adaptively in blind, training, and decision-directed modes. A direct connection provided from the equalizer output to the DFF facilitates coarse signal acquisition and equalization during the blind operating mode.

Abstract: A radio receiver for receiving a selected digital HDTV signal, irrespective of whether it is a complex-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal, using the same tuner. The tuner supplies a final IF signal in a 6 MHz frequency band, the lowest frequency of which is not appreciably more than 2.38 MHz. The final IF signal is digitized for synchrodyning to baseband, with the 2.375 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 symbol frequency by applying automatic frequency and phase control signals developed in the digital circuitry to a local oscillator of the tuner. The presence of the pilot carrier accompanying a selected VSB HDTV signal is detected for automatically switching the radio receiver for operation in a VSB signal reception mode.

Abstract: A system for transmitting and receiving an uncompressed HDTV signal over a wireless RF link includes a clock that provides a clock signal synchronized to the uncompressed HDTV signal and a data regeneration module connected to the clock, which provides a stream of regenerated data from the uncompressed HDTV signal. A demultiplexer demultiplexes the stream of regenerated data, using the clock signal, into an I data stream and a Q data stream. A modulator connected to the demultiplexer modulates a carrier with the I data stream and the Q data stream. A demodulator receives the carrier and demodulates the carrier so that the I data stream and the Q data stream are recovered. A multiplexer connected to the demodulator multiplexes the I data stream and the Q data stream into a single stream of HDTV data so that the uncompressed HDTV signal is recovered.

Abstract: The MPEG2TS packet S3 as the digital broadcast data is obtained from the ECC decoder. The NIT detecting circuit detects NIT from this packet S3, changes the transmitting frequency information and deletes the information (service information) of the program to be limited for viewing, thereby to obtain the table NITb. The NIT replacing circuit detects NIT from the packet S3 and replaces it to the table NITb, thereby to obtain the MPEG2TS packet S4 as the digital broadcast data in CATV. The digital broadcast signal BS1 for CATV can be obtained by executing the error correction code adding process, modulating process and frequency-converting process to the packet S4. The receiving apparatus for receiving the predetermined program on the basis of the program information of NIT can no longer receive the program in relation to the program information deleted by NIT.

Abstract: Disclosed is a digital TV receiver including an A/D converter for converting an analog signal into a digital signal, a carrier recovery for converting the digital passband signal into a digital baseband signal, and a symbol clock recovery for converting digital baseband real/imaginary component signals into OQAM type of real/imaginary component signals, detecting timing error information by high-passband-filtering, squaring, and adding the OQAM real/imaginary signals, and for generating and outputting the at least two times the frequency of the symbol clock corrected from the detected timing error information.

Abstract: A signal of a desired channel is selected by a tuner from digital broadcasting is received by an antenna. The condition of the radio wave received by the antenna, which is judged from an AGC signal of the signal of the channel selected by the tuner, a Sync signal detected by a synchronization establishment unit and the number of errors which have not been corrected by a forward error corrector 10, is displayed on an indicator. The receiving direction or position of the antenna can be easily decided on the basis of the condition of the received radio wave of the antenna, which is displayed on the indicator, so that received video has a C/N within thresholds.

Abstract: The cost of a receiving unit is reduced by simplifying its structure and the receiving unit structure further reduces the unit from being influenced by noises and the like generated by the main body of the television receiver. A digital television signal receiving unit includes of a metallic case, a frequency conversion circuit housed in the metallic case for converting a frequency of a received digital television signal into an intermediate frequency signal or a base band signal and an OFDM signal processing circuit for processing either the intermediate frequency signal or the base band signal and outputting an MPEG bit stream signal. Operations of the frequency conversion circuit and the signal processing circuit are controlled by a control signal outputted from a control circuit arranged outside the metallic case.

Abstract: A color system discriminator is provided with a frequency detector, a vertical-synchronizing frequency detector, a plurality of color demodulators, a demodulating switch, and a controller. The type of the color system of a received signal is determined with reference not only to the burst lock frequency indicated in the tuner detection signal and the phase of the R-Y color difference signal of the image signal, but also to the frequency of the sound carrier signal and the vertical synchronizing frequency.

Abstract: A method and apparatus that identifies the degree of correlation between a demodulated in-phase (I) and quadrature (Q) signal that represents phase imbalance between the in-phase (I) and quadrature (Q) signal and corrects the imbalance.

Abstract: Device and method for tracking a phase error in a digital TV receiver, wherein a phase noise compensated I signal is subtracted from I level reference signals of VSB signal, to obtain an error of the I signal, a sign of the Q signal having a phase noise thereof compensated is multiplied to the error of the I signal from the error determining part, to estimate a basic phase error, and a phase error compensating area is determined, a preset constant ‘&agr;’ is multiplied to the basic phase error to provide a final phase error in the determined phase error compensating area, and the basic phase error is provided as it is as the final phase error in other areas, thereby estimating the phase error more accurately.

Abstract: A high frequency receiver of the present invention has a mixer of which one input part is connected to an output part of a filter and the other input part is connected to an output part of a frequency-variable local oscillator, and an output terminal connected to an output part of the mixer. The mixer is an image rejection mixer. The filter has a moderated damping characteristic in a frequency where the image rejection mixer reduces an image. Therefore, a high performance filter is not required, and hence a low price is realized.

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 VSB reception system includes a sequence generator for decoding a symbol corresponding to the supplemental data and generating a predefined sequence included in the supplemental data at VSB transmission system. The reception system also includes a modified legacy VSB receiver for processing the data received from the VSB transmission system in a reverse order of the VSB transmission system by using the sequence, and a demultiplexer for demultiplexing the data from the modified legacy VSB receiver into the MPEG data and the supplemental data. The VSB reception system also includes a supplemental data processor for processing the supplemental data segment from the demultiplexer in a reverse order of the transmission system, to obtain the supplemental data, thereby carrying out the slicer prediction, decoding, and symbol decision more accurately by using the predefined sequence, to improve a performance.

Abstract: A routing device is provided for transporting digital data from demodulated digital television signals. The routing device includes a network that routes the digital data to demultiplexers via at least one decoding module. The network includes means for connecting to at least two independent demodulation channels, with each of the demodulation channels producing digital data from a demodulator. The network allows individual routing of the digital data from each of the demodulation channels to the demultiplexers via at least one decoding module. Also provided are a corresponding routing method and a host device that includes such a routing device. Exemplary applications of the routing device and method are a digital television receiver with an image incorporation (picture in picture) function, and a digital television combined with a recording device.

Abstract: A demodulator for a high definition television receiver includes a first circuit element which receives a signal, and is operative in a first arrangement to produce an output signal having a first dynamic range, and operative in a second arrangement to produce an output signal having a second dynamic range different from the first dynamic range. A second circuit element is arranged for optimally processing a signal having a substantially predetermined fixed dynamic range. A gain control circuit is coupled between the first and second circuit elements, and produces a signal having the substantially predetermined fixed dynamic range.

Abstract: A television tuner is fully implemented on a monolithic integrated circuit. The television tuner includes a baseband SAWF function fully integrated in silicon. The SAWF function includes trap and bandpass filters. A video demodulation circuit includes an I, Q demodulation and a post Nyquist filter.

Abstract: For use in a receiver capable of decoding trellis encoded signals, there is disclosed an apparatus and method for reducing error propagation in a decision feedback equalizer. The apparatus of the invention comprises a trellis decoder and a decision feedback equalizer coupled to the path memory outputs of the trellis decoder. The decision feedback equalizer is capable of obtaining symbol values from the trellis decoder and using the symbol values as estimates in channel equalization. In one embodiment of the invention, a first equalizer and trellis decoder combination is used to estimate a symbol stream. Then a second equalizer and trellis decoder combination is used to further minimize error by operating on the output of the first equalizer and trellis decoder combination.

Abstract: Disclosed is a method and apparatus for transmission of audio signals over a dedicated video transmission line in which the analog audio signal is inserted into and becomes a part of the video signal. Samples of the audio signal are inserted into the active video line, either at the beginnings or endings, or both, of each active video line scan signal. A defined amount of the active video interval is reserved from the active video line, and is replaced with samples of the analog audio signal. An analog switch in the modulator of the invention toggles to pick up the samples of audio and place them at the designated location (either at the beginnings or at the ends) of each active video line scan signal. A corresponding switch in the demodulator of the invention toggles to retrieve the audio samples from the active video line scans for output to the user. Stereo and/or bi-directional audio signals can be transmitted by insertion into both the beginnings and the endings of the active video line scan signals.

Abstract: A system for providing spectral compensation for vestigial sideband, VSB, signals with carrier frequency error. The VSB signal is sampled and digitized. The carrier frequency of the digitized signal is translated to a selected IF frequency. A fixed frequency VSB filter is then used to provide spectral compensation for the signal.

Abstract: Methods and apparatus are described for receiving digital television signals where the receiver is capable of demodulating and demultiplexing the digital television signals from multiple, independent transmission channels. The preferred embodiment of the present invention provides for a Dual Channel Digital TV Receiver which receives signals from two independent transmission channels. In order to address each of the digital television signals from the two independent transmission channels, the Dual Channel Digital TV Receiver of the preferred embodiment of the present invention includes two independent paths for channel demodulation and transport stream demultiplexing. Thus, within the Dual Channel Digital TV Receiver of the preferred embodiment of the present invention, a signal from each of the transmission channels are received, decoded and sent for further processing or viewing, as desired by the user.

Abstract: A tuner unit generates a local oscillation signal which is multiplied by a received first IF signal to change the frequency of the received first IF signal, and converts the frequency-changed first IF signal into a baseband signal. A demodulation unit detects the signal level of demodulated data, and notifies the signal level to a control unit. The control unit compares the signal level notified by the demodulation unit with a reference value stored in a storage unit, and if the signal level is equal to or smaller than the reference value, makes the tuner unit change the frequency of a local oscillation signal to be used for frequency conversion of the first IF signal and perform a channel selection in a next frequency range. Time taken to start providing a service can therefore be shortened.

Abstract: A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information and a pilot component includes an input analog-to-digital converter (19) for producing a datastream which is oversampled at twice the received symbol rate, and a digital demodulator (22; FIG. 3) with a data reduction network (330, 332) in a phase control loop. A segment sync detector (24; FIG. 4, 5) uses an abbreviated correlation reference pattern to recover a twice symbol rate sampling clock for the digital converter (19). A DC offset associated with the pilot component is removed (26; FIG. 6) from the demodulated signal before it is applied to an NTSC interference detection network (30; FIG. 7). The interference detection network includes a comb filter network (710, 718) responsive to a twice symbol rate sampled data datastream, and exhibits a sample delay dimensioned to avoid aliasing in the combed frequency spectrum (FIG.

Abstract: An adaptive channel equalizer (50) for processing a demodulated VSB signal containing terrestrial broadcast high definition television information operates adaptively in blind, training, and decision-directed modes. The VSB signal is characterized by a data frame format (FIG. 2) constituted by a succession of data fields each containing a data segment prefaced by a field sync segment. Equalization is expedited by recycling (35) received training data through the equalizer more than once during a VSB data field after a field sync segment is detected.

Abstract: A method is presented for demodulating and decoding a block of received digital information consisting of a number of subblocks. One of a predefined number of demodulation methods is selected for demodulating each subblock and each subblock is demodulated with the demodulation method selected for it. The subblocks constituting a block of digital information are combined between their demodulation and the decoding of the block of digital information. Soft decoding is used to decode the block of digital information, wherein each subblock is converted to a sequence of soft decoding values associated with certain probabilities of allowed state transitions in the decoding process. For each subblock it is determined, after its demodulation, whether the correct demodulation method was selected for it.

Abstract: A receiver for VSB signals includes tuner channel changing circuitry. AGC circuitry, an IF FPLL and confidence counters, for indicating when signal acquisition or loss occurs. When a loss of signal indication is generated, the IF FPLL is reset, but not the tuner channel changing circuitry and the AGC circuitry, in order to quickly reacquire the signal. If the loss of signal indication persists for a predetermined time or for a predetermined number of loss of signal indications, the IF FPLL, the tuner channel changing circuitry and the AGC circuitry are all reset to reacquire the signal.

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

Abstract: The present invention uses multiple broadcast television channels to distribute high volume of data to a client device from a server. Multiple analog channels are broadcast, at least one of which contains video/audio programs and control data inserted into the analog signal's VBI; and at least one separate channel contains a digital data stream which is modulated onto an analog channel and associated with channels containing those video/audio programs. STBs designed to implement this invention are equipped with at least two tuners in order to tune to two of those channels simultaneously. One tuner is used to tune to the video/audio channel, and extract the control data in the VBI. The second tuner is used to tune to the channels containing the data itself.

Abstract: In a receiver for receiving digital television (DTV) signals with carriers near the upper frequency boundaries of TV broadcasting channels, co-channel interfering NTSC video carrier and its lower frequency sidebands are removed from intermediate-frequency signal by trap filtering, preferably in SAW filtering used in the intermediate-frequency amplifier. Co-channel interfering NTSC chroma burst and lower frequency chroma sidebands also are removed from intermediate-frequency signal by trap filtering. Artifacts of co-channel interfering NTSC audio signal in baseband DTV signal recovered by in-phase synchrodyne circuitry are cancelled using Hilbert-transformed artifacts of co-channel interfering NTSC audio signal recovered by quadrature-phase synchrodyne circuitry.

Abstract: A television demodulator circuit, for use in a television receiver, generates baseband video and audio outputs from a television signal, such as an intermediate frequency television signal. The I, Q demodulator circuit mixes the television signal with an in-phase (“I”) local oscillator signal and a quadrature phase (“Q”) local oscillator signal at the tuned frequency to generate baseband I and Q signals. The baseband I and Q signals are input to low pass filters and a Nyquist slope filter. The Nyquist slope filter generates, for the baseband I and Q signals, a Nyquist slope response and attenuates channels adjacent to the tuned television channel. The Nyquist slope filter comprises a transfer function with at least two zero crossings, so as to provide a notch filter response for attenuation of a television channel adjacent to the tuned television channel.

Abstract: A digital broadcast recorder capable of recording a digital television (TV) signals, includes a first frequency converter which converts a received digitally modulated TV signal into a first intermediate frequency signal having a frequency lower than that of the digitally modulated TV signal, the first intermediate frequency signal having a frequency in a standard TV band and useable in demodulating standard TV signals, a band-pass filter coupled to the first frequency converter, which selectively passes-through the first intermediate frequency signal, a phase-lock loop (PLL) circuit coupled to the first frequency converter, which controls an oscillation frequency of a local oscillator in the first frequency converter, a second frequency converter coupled to the band-pass filter, which converts the first intermediate frequency signal passed through the band-pass filter into a second intermediate frequency signal lower in frequency than said first intermediate frequency signal a digital demodulator coupled to

Abstract: A method for the decoding of a signal in an interrogation/response type of communications system, the received signal being formed by a video signal and a signal containing the data, wherein the method comprises at least the following steps: 1) transposing the received data signal to an intermediate frequency Fl to obtain the signal Sdh(Fl), Sdb(Fl), 2) converting the intermediate frequency analog signal into a digital signal, 3) sampling the digital signal Sdh(Fl), Sdb(Fl) at a given frequency Fe to obtain the signal Seh, Seb, 4) transmitting the sampled signal Seh, Seb as well as the video signal Svh, Svb to a processing step so as to determine the initially received signal. The method can be applied to the demodulation of MSK, FSK, DPSK type waveforms.

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: Digital radio receivers for digital television signals often employ bandpass trackers in which the bandwidth of the automatic-frequency-and-phase-control (AFPC) loop is determined in the baseband by lowpass filtering after demodulating the intermediate frequency signal. If the I-F signal is vestigial-sideband in nature, and if baseband symbol code is designed to have a spectrum reaching at least substantially to zero-frequency, low-frequency modulation components tend to give rise to phase jitter in the AFPC loop. This is owing to the asymmetry of the modulation sidebands near carrier frequency. To reduce such phase jitter, a filter is introduced before the AFPC detector for reducing asymmetry of channel response in a narrow-frequency band including the pilot carrier signal.

Abstract: A receiver for broadcast signals, e.g. DAB, FM, DVB, and digital or analog short-wave RF broadcast signals according to the present invention includes a polyfunctional circuit (5) that can be switched into three modes and performs the digital frequency demodulation which is needed for the reception of a frequency modulated signal in a first mode A, a digital frequency adjustment of the receiver in case of the reception of a digital or analog modulated broadcast signal like DAB, DVB, DRM or AM in a second mode B and the digital frequency adjustment and the digital gain control of the receiver which is needed in case of the reception of a digitally modulated broadcast signal like DAB, DVB, DRM in a third mode C. Depending on the needed functionality not all of these modes need to be realized. Nevertheless, the same hardware will be used for different purposes although the circuit is realized with an optimized amount of hardware to realize an efficient receiver.

Abstract: A digital IF demodulator receives and demodulates an analog IF input signal to produce a digital audio signal and a digital video signal. The digital IF demodulator includes an A/D converter, a first digital complex mixer, a second digital complex mixer, and various digital filters. The first digital complex mixer receives the output of the A/D converter and down-converts the output of the A/D converter to baseband. Additionally, the picture carrier is recovered from the output of the first digital complex mixer, and fed back to a direct digital synthesizer to control the tuning accuracy of the first digital complex mixer. More specifically, a feedback loop is formed to so that the picture carrier is down-converted to DC so as to control the tuning accuracy of the first digital complex mixer. The complex output of the first complex mixer is further processed using Nyquist filtering and other filtering to recover the digital video 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: The invention provides a television reception circuit wherein a front end circuit of a television receiver is integrated and outputting of an image frequency is suppressed. The television signal reception circuit comprises an integrated circuit which in turn includes an automatic gain circuit for controlling a level of an input signal, first and second frequency mixture circuits to which an output of the automatic gain circuit is inputted, a &pgr;/2 phase shifting circuit for supplying local oscillation frequencies having a phase difference of &pgr;/2 from each other to the first and second frequency mixture circuits, first and second &pgr;/4 phase shifting circuits for shifting phases of outputs of the first and second frequency mixture circuits by +&pgr;/4 and −&pgr;/4, respectively, and an addition circuit for adding outputs of the first and second &pgr;/4 phase shifting circuits.

Abstract: A radio receiver for receiving a selected digital TV signal uses final intermediate frequency signals the carrier frequencies of which are multiples of symbol rate. The radio receiver has a match filter receptive of rectified samples of digitized intermediate-frequency signal and responsive to the amplitude of the intermediate-frequency carrier being modulated in accordance with the field synchronization code group to generate a pulsed response to the beginning of each data field. This pulsed response is used to determine when data segment synchronization information should occur, so its detection is more certain to be accurate and data segment synchronization is more rapidly determined. Symbol synchronization is rapidly inferred from the field synchronization and data segment synchronization, so that the samples in each data line can be counted.

Abstract: A digital television (TV) receiver using a vestigial sideband (VSB) system, and timing recovering apparatus and method for the digital TV receiver are disclosed. The timing error can be compensated for by rapidly and accurately searching the position of the segment sync signal using the Hilbert filter even if the strong 2-symbol-delayed ghost is applied. Also, the tracking performance for the timing error and the zitter performance can be improved by extracting the timing error information even from the signal having passed through the Hilbert filter.

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: The MPEG2TS packet S3 as the digital broadcast data is obtained from the ECC decoder. The NIT detecting circuit detects NIT from this packet S3, changes the transmitting frequency information and deletes the information (service information) of the program to be limited for viewing, thereby to obtain the table NITb. The NIT replacing circuit detects NIT from the packet S3 and replaces it to the table NITb, thereby to obtain the MPEG2TS packet S4 as the digital broadcast data in CATV. The digital broadcast signal BS1 for CATV can be obtained by executing the error correction code adding process, modulating process and frequency-converting process to the packet S4. The receiving apparatus for receiving the predetermined program on the basis of the program information of NIT can no longer receive the program in relation to the program information deleted by NIT.

Abstract: A circuit arrangement for demodulating an intermediate-frequency video signal, comprising a video demodulator (1) and a phase-locked loop (5) formed as a Costas loop, in which an output signal of a controllable oscillator (12) arranged in the Costas loop and the intermediate frequency video signal are coupled to the video demodulator (1), should always supply a demodulated video signal of a predetermined polarity, independent of overmodulation occurring in the intermediate-frequency video signal.

Abstract: The present invention provides a digital video receiving apparatus for displaying a plurality of digital TV pictures on a plurality of receiving terminal apparatuses. The digital video receiving apparatus includes a tuner for extracting the received digital TV multiplexed signal, a demodulator for decoding the digital signals provided from the tuner, a demultiplexer for demultiplexing the multiplexed signals outputted from the demodulator to obtain a bit stream including a video signal, an audio signal and a data signal. The digital video receiving apparatus further includes a video decoder, an audio decoder and a data decoder for decoding signals outputted from the demultiplexer. The digital video receiving apparatus decodes the input multiplexed digital TV signal and outputs a video signal, an audio signal and a data signal corresponding to respective programs.

Abstract: A TV decoder. The decoder comprises a converter producing a plurality of first bits by sampling a base-band TV signal within a sampling period, and transmitting the first bits in groups, wherein the first bits in each one of the groups undergo parallel transmission through a plurality of first signals, and a demodulator receives the first bits and produces a plurality of second bits controlling the first signals, wherein the second bits are sequentially transmitted through a second signal input to the converter.

Abstract: An upconverter for converting IF television signals to VHF or UHF signals prior to broadcast is configured to process either analog or digital television signals. The upconverter identifies the type of incoming television signal and generates an appropriate reference signal depending on whether the incoming television signal is digital or analog. In an analog format, the reference signal is used by the modulator generating the IF signal to synchronize phase with the signals output by various other upconverters. In a digital format, the reference signal is used, for example, as a test signal for the upconversion circuit.

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 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. 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 (AFPC) signals developed in the digital circuitry to a local oscillator of the tuner. Baseband DTV signals obtained by synchrodyning the final IF signals have a sample rate higher than symbol rate to facilitate symbol synchronization. The baseband DTV signals are decimated to symbol rate before performing channel equalization to reduce the number of multipliers required in the channel equalization filter.