Vestigial Sideband Patents (Class 455/204)
  • Patent number: 8861581
    Abstract: Provided is a receiver for processing VSB signal. The receiver includes a first equalizer/decoder unit and a second equalizer/decoder unit. The first equalizer/decoder unit performs a first equalizing operation, first TCM decoding and first RS decoding on a received symbol to output a first dibit. The second equalizer/decoder unit performs a second equalizing operation, second TCM decoding and second RS decoding on the received symbol to output a transport stream. The first dibit is provided as a priori information for a soft-decision operation of the second TCM decoding.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: October 14, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: DoHan Kim, Sergey Zhidkov, Beom kon Kim
  • Patent number: 8699600
    Abstract: A frequency and data synchronization control system through the 8VSB SFN DTx modulation prevents the deterioration of the digitally broadcasted receiving sensitivity caused by a discrepancy of the frequency or data between the receiver of the digital broadcasting signal and the distributed translator or between distributed translators.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: April 15, 2014
    Assignee: K-Tech Telecommunications, Inc
    Inventor: Steve Kuh
  • Patent number: 8364179
    Abstract: A method for communication includes transmitting data from a transmitter to a receiver using Adaptive Coding and Modulation (ACM). The data rate is set by selecting, based on feedback, an ACM profile defining a Forward Error Correction code and a modulation scheme. Upon detecting that the feedback is unusable, an operation of the transmitter is changed independently of the feedback. In another method, data is exchanged over two opposite directions of a bidirectional link that uses ACM by communicating using two ACM profiles. A joint constraint is defined on the two directions. The two ACM profiles are set based on first and second measured reception quality metrics of the two link directions, to meet the joint constraint. In yet another method, a subset of the ACM profiles is temporarily disabled, and the data is transmitted using only the ACM profiles that are not disabled.
    Type: Grant
    Filed: March 31, 2010
    Date of Patent: January 29, 2013
    Assignee: Provigent Ltd.
    Inventors: Ehud Ashkenazi, Jonathan Friedmann
  • Patent number: 8340025
    Abstract: In one illustrative example, a mobile communication device receives and decodes a plurality of packet data bursts over a packet data channel of a serving cell. While receiving and decoding the packet data bursts, the mobile communication device also receives and decodes a plurality of broadcast data bursts over a broadcast control channel of a neighbor cell. When a time conflict exists between receiving and decoding at least one of the packet data bursts and receiving and decoding at least one of the broadcast data bursts, the mobile communication device receives and decodes the at least one packet data burst instead of the at least one broadcast data burst when no imminent call drop between the mobile communication device and the serving cell is identified.
    Type: Grant
    Filed: May 27, 2010
    Date of Patent: December 25, 2012
    Assignee: Research In Motion Limited
    Inventor: Matthias Wandel
  • Patent number: 8300569
    Abstract: A method of processing broadcast data in a broadcast transmitter includes performing, by a Reed-Solomon (RS) encoder, RS encoding and Cyclic Redundancy Check (CRC) encoding on mobile service data and building at least primary RS frames belonging to a primary ensemble or secondary RS frames belonging to a secondary ensemble depending on RS frame mode information that indicates a single frame mode or a dual frame mode; mapping each of the built at least primary or secondary RS frames into groups, wherein each of the groups includes known data sequences, a fast information channel (FIC) segment, and transmission parameter channel (TPC) data; and transmitting a transmission frame containing the groups.
    Type: Grant
    Filed: February 27, 2012
    Date of Patent: October 30, 2012
    Assignee: LG Electronics Inc.
    Inventors: Jae Hyung Song, In Hwan Choi, Jong Yeul Suh, Jin Pil Kim, Chul Soo Lee
  • Patent number: 8284089
    Abstract: A cyclic digital-to-analog converter includes a first capacitor and a second capacitor. Switching circuitry is selectively configurable to connect the first and second capacitors is at least two modes of operation, wherein a first mode uses the first capacitor during conversion of a bit as a sampling capacitor and uses the second capacitor during conversion of that bit as a holding capacitor, and wherein a second mode uses the second capacitor during conversion of a bit as a sampling capacitor and uses the first capacitor during conversion of that bit as a holding capacitor. A controller swaps converter operation between the first and second modes based on the bit values of a digital word to be converted. If adjacent bits of the digital word to be converted have different logical values, the converter swaps from the first mode to the second mode (or from the second mode to the first mode). Otherwise, the converted remains in the current first or second mode.
    Type: Grant
    Filed: December 9, 2010
    Date of Patent: October 9, 2012
    Assignee: STMicroelectronics Asia Pacific Pte Ltd
    Inventor: Yannick Guedon
  • Patent number: 8175193
    Abstract: An apparatus for recovering carrier wave in digital broadcasting receiver and a method therefore are disclosed which are capable of easily detecting and correcting frequency offsets of carrier wave without recourse to a pilot signal in a digital broadcasting receiver receiving a broadcasting signal of vestigial sideband (VSB) modulation system, thereby recovering the carrier wave, wherein, to this end, a complex sine wave whose central frequency is 1/n the symbol frequency is multiplied to generate a real component and imaginary Offset Quadrature Amplitude Modulation (OQAM) signals to calculate a phase error value from the real and imaginary component OQAM signals, to generate a complex sine wave compensating the calculated phase error value, to multiply the complex sine wave by the complex signal outputted from the phase splitter and to convert the complex signal to a baseband signal whose frequency offset is corrected.
    Type: Grant
    Filed: March 28, 2008
    Date of Patent: May 8, 2012
    Assignee: LG Electronics Inc.
    Inventor: Jae Hyung Kim
  • Patent number: 8150325
    Abstract: An exemplary signal interference control system is disclosed that utilizes a computer system, such as programmable logic circuits or computer controlled logic gates, to generate blanking or control signals for various types of radio frequency receiver and transmitter combinations. Control signals are generated based on signal characteristic information stored in a memory including a delay following receipt of a pre-trigger signal from a radio frequency transmitter and a pulse width of control signal(s) generated for specified receivers, frequencies or systems. In one embodiment, information can be retrieved from a memory and used to generate an interference control signal. One or more control signals can be routed to a related or associated receiver to reduce or eliminate interference effects.
    Type: Grant
    Filed: June 12, 2008
    Date of Patent: April 3, 2012
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Brad A. Prichard
  • Patent number: 8130873
    Abstract: A carrier recovery apparatus usable with a VSB receiver and a method thereof. The carrier recovery apparatus is capable of recovering a carrier even though a pilot signal may be corrupted due to multi-path characteristics of a channel. Accordingly, the carrier recovery apparatus performs a BECM (Band Edge Component Maximization) algorithm on upper and lower sidebands of a received signal to generate phase information therefrom. The phase information is combined in a combiner. Since the BECM algorithm is performed on the upper and lower sidebands, it is possible to execute the carrier recovery even through the upper sideband of a received signal may be corrupted. Therefore, the carrier recovery apparatus can prevent performance degradation of the VSB receiver caused by corruption in the pilot signal.
    Type: Grant
    Filed: August 9, 2005
    Date of Patent: March 6, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Dong-hoon Lee
  • Patent number: 7738616
    Abstract: A phase tracking system includes a source of an input signal representing a received symbol. A phase rotator has a first input terminal which is responsive to the input signal, a second input terminal which is responsive to a phase correction signal, and an output terminal which produces a phase adjusted output signal. A decision element generates an ideal signal representing the received symbol in response to the phase adjusted output signal. A phase adjuster, which has full phase wrap-around capability, generates the phase correction signal in response to the phase difference between the phase adjusted output signal and the ideal signal.
    Type: Grant
    Filed: April 16, 2002
    Date of Patent: June 15, 2010
    Assignee: Thomson Licensing
    Inventor: Ivonete Markman
  • Patent number: 7634029
    Abstract: A symbol timing recovery apparatus used with a VSB-type receiver and a method of the same. In order for the symbol timing recovery, error information is generated and used utilizing a band edge component maximization (BECM) of a frequency band as well as an upper frequency band. Therefore, the symbol timing recovery can be more effectively achieved even when the upper frequency band is damaged due to multi-path components. Also, efficiency of the overall timing recovery can be improved by using the lower frequency band as well as the upper frequency band of the received signal in performing the symbol timing recovery. As a result, deterioration of the receiving system including the symbol timing recovery apparatus can be prevented.
    Type: Grant
    Filed: August 23, 2005
    Date of Patent: December 15, 2009
    Assignee: Samsung Electronics Co., Ltd
    Inventor: Dong-hoon Lee
  • Publication number: 20090258620
    Abstract: A terminal is provided. The terminal comprises a tuner converting a received high-frequency signal, a VSB (vestigial side band) demodulator demodulating the output signal of the tuner into a VSB signal, a DMB (digital multimedia broadcasting) demodulator demodulating the output signal of the tuner into a DMB signal, a decoder decoding the demodulated VSB signal or the demodulated DMB signal into an image signal, and a controller controlling at least one of the tuner, the VSB demodulator, the DMB demodulator, and the decoder.
    Type: Application
    Filed: December 24, 2007
    Publication date: October 15, 2009
    Inventor: Jae Kil Jung
  • Publication number: 20090227221
    Abstract: In a VSB system, a method for channel modeling to estimate coefficients corresponding to a selected subspace is provided. The method comprises the steps of: selected a predetermined subspace; creating a set of bi-orthogonal vectors for the initially selected subspace; and obtaining a set of coefficients by solving a linear programming problem. Whereby the resultant channel is constructed by the coefficients and their associated subspace.
    Type: Application
    Filed: March 6, 2008
    Publication date: September 10, 2009
    Applicant: LEGEND SILICON CORP.
    Inventors: LIN YANG, QIN LIU
  • Publication number: 20090055865
    Abstract: The present invention provides a method of processing data. The method of processing data includes receiving a broadcasting signal where mobile service data are multiplexed with main service data, extracting transmission-parameter-channel signaling information and fast-information-channel signaling information from a data group within the received mobile service data; obtaining first program table information describing virtual channel information of an ensemble and a service provided by the ensemble using the fast-information-channel signaling information, the ensemble the ensemble corresponding to a virtual channel group of the received mobile service data, obtaining information indicating that second program table information, which describes an additional service provided by the ensemble, is included in the ensemblem and parsing the second program table information according to the obtained information; and providing the additional service by using the second program table information.
    Type: Application
    Filed: August 25, 2008
    Publication date: February 26, 2009
    Inventors: Hui Sang Yoo, In Hwan Choi, Chul Soo Lee, Jae Hyung Song, Min Sung Kwak
  • Publication number: 20090046815
    Abstract: A digital broadcasting system which is robust against an error when mobile service data is transmitted and a method of processing data are disclosed. The mobile service data is subjected to an additional coding process and the coded mobile service data is transmitted. Accordingly, it is possible to cope with a serious channel variation while applying robustness to the mobile service data.
    Type: Application
    Filed: July 2, 2008
    Publication date: February 19, 2009
    Inventors: Hyen O. Oh, In Hwan Choi, Kook Yeon Kwak, Byoung Gill Kim, Won Gyu Song, Jin Woo Kim, Hyoung Gon Lee
  • Patent number: 7474990
    Abstract: The present invention provides a novel symbol timing recovery method for VSB receivers. Systems are described that comprise a timing error detector (TED) that produces an exact symbol timing error even in the presence residual carrier phase offset, loop filter that controls the characteristics of acquisition and tracking of digital PLL loop, Voltage/Numerically Controlled Oscillator (VCO/NCO) that adjusts the sampling instant and phase, A/D converter that samples a continuous VSB input signal, and a interpolating squared root raised cosine filter that performs both matched filtering and a compensation of constant timing offset of quarter symbol caused by the invented TED. The timing error detector in this invention comprises an envelope detector, band pass filter, squaring block, high pass filter, and decimator.
    Type: Grant
    Filed: September 29, 2006
    Date of Patent: January 6, 2009
    Assignee: Techwell, Inc.
    Inventor: Joon Tae Kim
  • Patent number: 7450658
    Abstract: At the transmitter of a transmitter and receiver apparatus for Multiple Input/Multiple Output MultiCarrier-Code Division Multiple Access (MIMO MC-CDMA) systems, modified orthogonal transmit diversity (MOTD) encoders are used for increasing space and time transmission diversity. A P-way combiner is used to connect the MOTD encoders and P multi-carrier modulators. Each modulator is connected to a set of antennas. At the receiver, each multi-carrier demodulator has an amplitude/phase compensator to compensate distortion at every sub-carrier. Similarly, a combiner is used to connect the demodulators and the MOTD decoders. As a result, space, time, and frequency diversity can be explored.
    Type: Grant
    Filed: August 2, 2007
    Date of Patent: November 11, 2008
    Assignee: Industrial Technology Research Institute
    Inventors: Jiann-An Tsai, Shih-Kai Lee, Chang-Lung Hsiao
  • Patent number: 7433417
    Abstract: The invention relates to a receiver (1, 49, 51, 52, 54) for receiving RF signals. The known receiver comprises a phase-locked loop which is controlled by the stereo pilot. Because of unwanted frequency changes, a sampling rate converter precedes the stereo decoder. Filtering operations within a complex range can be performed by means of the invention.
    Type: Grant
    Filed: February 17, 2003
    Date of Patent: October 7, 2008
    Assignee: NXP B.V.
    Inventors: Wouter Joos Tirry, Ludovic Albert Jozef Van Paepegem
  • Patent number: 7349354
    Abstract: The present invention may relate to the following steps. Converting a bundle of data from a first format of a first mobile switching center to a second format of a switch. Routing, at the switch, the bundle data in the second format. Converting the bundle of data from the second format to a third format of the second mobile switching center. The first format and the third format are different formats. Mobile switching centers manage and operate base stations. The first mobile switching center and the second mobile switching center may be owned and operated by different companies. Accordingly, the first and second mobile switching centers will operate using different formats (or protocols). This is made possible by converting data between formats so it can be routed at a switch. This provides a particular advantage. A cell phone can now transparently change between base stations that are owned and operated by different companies.
    Type: Grant
    Filed: November 20, 2002
    Date of Patent: March 25, 2008
    Assignee: LG Electronics Inc.
    Inventor: Sung Hyun Yun
  • Patent number: 7330513
    Abstract: The invention relates to an apparatus of transmitter and receiver for Multiple Input/Multiple Output MultiCarrier-Code Division Multiple Access (MIMO MC-CDMA) systems. At the transmitter, modified orthogonal transmit diversity (MOTD) encoders are used for increasing space and time transmission diversity. A P-way combiner is used to connect the MOTD encoders and P multi-carrier modulators. Each modulator is connected to a set of antennas. At the receiver, each multi-carrier demodulator has an amplitude/phase compensator to compensate distortion at every sub-carrier. Similarly, a combiner is used to connect the demodulators and the MOTD decoders. Upon the invention, the space, time, and frequency diversity can be explored.
    Type: Grant
    Filed: June 17, 2004
    Date of Patent: February 12, 2008
    Assignee: Industrial Technology Research Institute
    Inventors: Jiann-An Tsai, Shih-Kai Lee, Chang-Lung Hsiao
  • Patent number: 7272197
    Abstract: Device for recovering a carrier including a first signal converter for multiplying a complex carrier caused by a phase error to a digitized passband VSB signal, to provide a baseband VSB signal, a second signal converter for multiplying a complex value of a frequency to the signal from the first signal converter, to convert the baseband VSB signal into an OQAM signal, an error estimating part for generating a signal having carrier phase error information by using a real component and an imaginary component of the OQAM signal, and an oscillator for generating a complex carrier according to the carrier phase error information, thereby making carrier recovery regardless of a pilot component of TV signal, accurately.
    Type: Grant
    Filed: September 30, 2003
    Date of Patent: September 18, 2007
    Assignee: LG Electronics Inc.
    Inventor: Yong Suk Hwang
  • Patent number: 7231002
    Abstract: An apparatus and method of detecting whether the carrier frequency is locked for confirming recovering carrier is normally performed is disclosed. The apparatus includes a lock detector for judging whether the carrier frequency is locked by extracting DC value form real number component and imaginary component of an OQAM signal, and comparing the accumulated DC value to set value.
    Type: Grant
    Filed: October 14, 2003
    Date of Patent: June 12, 2007
    Assignee: LG Electronics Inc.
    Inventor: Yong Suk Hwang
  • Patent number: 7177609
    Abstract: A chopper-direct-conversion (CDC) radio receiver includes a phase-alternating mixer receiving an antenna input signal and at least one local oscillator signal and generating a double sideband signal in a single mixing step. The phase-alternating mixer may be implemented by two parallel mixers each mixing the input signal with one of two local oscillator signals and an adder receiving and summing outputs from the two parallel mixers, by a track-and-hold circuit sampling the input signal based upon the local oscillator signal, or by a window averaging circuit averaging the input signal across a period of the local oscillator signal. The CDC architecture is suitable for fabrication on a single chip and offers solutions to virtually all problems found in conventional direct-conversion receivers.
    Type: Grant
    Filed: May 16, 2003
    Date of Patent: February 13, 2007
    Assignee: National Semiconductor Corporation
    Inventor: Hee Wong
  • Patent number: 7061977
    Abstract: An apparatus and method is disclosed for using adaptive algorithms to exploit sparsity in target weight vectors in an adaptive channel equalizer. An adaptive algorithm comprises a selected value of a prior and a selected value of a cost function. The present invention comprises algorithms adapted for calculating adaptive equalizer coefficients for sparse transmission channels. The present invention provides sparse algorithms in the form of a Sparse Least Mean Squares (LMS) algorithm and a Sparse Constant Modulus Algorithm (CMA) and a Sparse Decision Directed (DD) algorithm.
    Type: Grant
    Filed: September 10, 2001
    Date of Patent: June 13, 2006
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Richard K. Martin, Robert C. Williamson, William A. Sethares
  • Patent number: 7016659
    Abstract: In an AM system directed to commercial broadcasting, a pure unmodulated (CW) carrier signal and two sideband signals are generated and processed separately as three independent signals that are summed as output of a final linear mixer. The sideband signals are derived independently utilizing audio spectrum-sharing based on complementary comb filtering, quadrature phase-shifting at both audio and carrier sideband frequencies, and exclusive alternate toggling at a designated switching rate between the two sidebands so that at any instant in time only one of the two sidebands is present along with the continuous carrier. The overall performance provides the capability of advantageous modulation beyond the conventional 100% modulation limit.
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: March 21, 2006
    Inventors: Michael L. Dorrough, Dennis Robert Lee, Alfred Edward Parker, Richard Williamson Burden
  • Patent number: 7010269
    Abstract: A free-running sample rate converter and a large spanning, non-linear pre-equalizer are employed before a timing recovery loop within a wireless receiver chain, while forward and feedback equalization after the timing recovery loop (at and around the input of a sync detector) is also retained. A channel identifier produces a channel estimate from the PN511 training sequence within the received wireless signals, with the pre-equalizer employing the resulting channel estimate to equalize the received signals being passed to the timing recovery loop, improving the signal quality for carrier and timing recovery and decoding to increase the probability of successful decoding while enabling the use of fast tracking forward and feedback equalizers for decoding.
    Type: Grant
    Filed: May 7, 2001
    Date of Patent: March 7, 2006
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Joseph Patrick Meehan, David Koo
  • Patent number: 6950481
    Abstract: A vestigial-sideband (VSB) signal is converted to a double-sideband amplitude-modulation signal having information that is subsequently detected in the double-sideband amplitude-modulation signal. A method for performing the conversion includes mixing the VSB signal with a first beat frequency different from a carrier frequency of the VSB signal, the first beat frequency being of such value as to generate a first mixing result that is translated in frequency to have a carrier at an offset frequency; mixing the VSB signal with a second beat frequency different from the carrier frequency of the VSB signal and from the first beat frequency, the second beat frequency being of such value as to generate a second mixing result that is translated in frequency to have a earner at the offset frequency; and combining the first and second mixing results to form the double-sideband amplitude-modulation signal with a carrier frequency at the offset frequency.
    Type: Grant
    Filed: June 13, 2003
    Date of Patent: September 27, 2005
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Allen LeRoy Limberg
  • Patent number: 6891898
    Abstract: The system for recovering symbol timing offset and carrier frequency error from an orthogonal frequency division multiplexed (OFDM) signal includes a receiver circuit for receiving an OFDM modulated signal representing a series of OFDM symbols, and providing a received signal to an output thereof. A peak development circuit is included for developing a signal having a plurality of signal peaks representing symbol boundary positions for each received OFDM symbol, where each of the signal peaks is developed responsive to an amplitude and phase correspondence produced between the leading and trailing portions of each of the received OFDM symbols. The system includes a circuit for enhancing the signal peak detectability, which includes a circuit for additively superimposing and then filtering the signal peaks, to produce an enhanced signal peak having an improved signal-to-noise ratio.
    Type: Grant
    Filed: October 23, 2002
    Date of Patent: May 10, 2005
    Assignee: iBiquity Digital Corporation
    Inventors: Paul James Peyla, Joseph Bertram Bronder
  • Publication number: 20040246072
    Abstract: A resonator device including a plurality of resonance units formed on a dielectric substrate, each resonance unit having a plurality of conductor lines forming a capacitive area and an inductive area in a ring shape.
    Type: Application
    Filed: June 2, 2004
    Publication date: December 9, 2004
    Inventors: Seiji Hidaka, Shin Abe
  • Publication number: 20030078023
    Abstract: A backward compatible enhancement to ATSC-VSB transmissions is provided to enable intra-field channel estimation for better channel equalization. One or more time-frequency waveforms are inserted into the transmitted signal with systematic time and frequency variation synchronized to the currently available field sync. A coherent demodulator may then directly estimate the channel frequency response. The power of the inserted waveform(s) is small compared to the existing 8-VSB signal, such that existing receivers will function as intended with only minimal degradation of performance.
    Type: Application
    Filed: October 23, 2001
    Publication date: April 24, 2003
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Krishnamurthy Vaidyanathan, Geoffrey F. Burns
  • Patent number: 6539063
    Abstract: The system for recovering symbol timing offset and carrier frequency error from an orthogonal frequency division multiplexed (OFDM) signal includes a receiver circuit for receiving an OFDM modulated signal representing a series of OFDM symbols, and providing a received signal to an output thereof. A peak development circuit is included for developing a signal having a plurality of signal peaks representing symbol boundary positions for each received OFDM symbol, where each of the signal peaks is developed responsive to an amplitude and phase correspondence produced between the leading and trailing portions of each of the received OFDM symbols. The system includes a circuit for enhancing the signal peak detectability, which includes a circuit for additively superimposing and then filtering the signal peaks, to produce an enhanced signal peak having an improved signal-to-noise ratio.
    Type: Grant
    Filed: February 18, 1999
    Date of Patent: March 25, 2003
    Assignee: Ibiquity Digital Corporation
    Inventors: Paul James Peyla, Joseph Bertram Bronder
  • Patent number: 6418164
    Abstract: An adaptive equalizer for use in blind equalization systems to compensate for transmission channel distortion and noise in a digital communication system uses multiple quantization levels for implementation of the Constant Modulus Algorithm (CMA). Different quantization levels are used in different regions of the CMA error function for both passband and baseband equalizers. In one embodiment, a quantizer with a step rise having logarithmic scale is used to digitize the CMA error function. In particular, a quantizer with a step rise in which each level of the quantizer step rise is a power of 2 is used to digitize the CMA error function. In another embodiment, a quantizer with a step rise in which each level of the quantizer step rise is the sum of two or more logarithmic scales is used to digitize the CMA error function.
    Type: Grant
    Filed: January 14, 1999
    Date of Patent: July 9, 2002
    Assignee: Nxtwave Communications, Inc.
    Inventors: Thomas J Endres, Samir N Hulyalkar, Christopher H Strolle, Troy A Schaffer
  • Patent number: 6351293
    Abstract: A decision directed phase detector that uses the quantized data output from a slicer to aid the phase error detection process to determine a phase error of a complex signal such as a vestigial sideband (VSB) signal containing in phase (I) and quadrature phase (Q) components (I and Q signals). The phase detector comprises subtractor having one input coupled to the I signal and a second input coupled to the data output of the slicer representing the magnitude of a sample point within a symbol. The quantized signal is subtracted from the I signal to produce &Dgr;I signal. The Q signal is processed to determine its sign and magnitude. The sign and magnitude values are multiplied together and the result is multiplied with the &Dgr;I signal to produce the phase error between the I and Q signals. This phase error signal is used in a digital television receiver to extract a data signal from a VSB signal for demodulation.
    Type: Grant
    Filed: July 13, 1998
    Date of Patent: February 26, 2002
    Assignees: Sarnoff Corporation, Motorola Inc.
    Inventor: Randall Bret Perlow
  • Patent number: 6154505
    Abstract: A broadcast receiving apparatus provides multifunctionality to cope with analog modulated input signals as well as digital input signals modulated by various types of modulation schemes. The apparatus comprises a detector for detecting the modulation scheme of input signals, and a switch for switching one or more of the characteristic of a filtering section, an amplifying section, and a detection section, depending upon the detected modulated scheme.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: November 28, 2000
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takaaki Konishi, Kazuya Ueda, Hisaya Kato, Kunio Ninomiya
  • Patent number: 5875389
    Abstract: An SSB radio receiver having an inexpensive wide-band IF filter which passes through not only a reception objective SSB station IF signal but also an interference SSB station IF signal simultaneously. These signals are SSB-detected to reproduce the original modulating audio signals with a BFO frequency, the BFO frequency itself located out of the pass-band of the wide-band IF filter. The frequency of the reception objective SSB station IF signal is selected to be nearest to the BFO frequency, preferably at an end of the pass-band width of the IF filter. Frequency spectrums of the SSB-detected audio signals are separated by a frequency difference comprising the difference between the BFO signal and the IF signals. The SSB-detected audio signals are applied to a selected low-pass filter, such as an inexpensive active filter, having a pass-band which covers or passes only the SSB-detected audio signal of the reception objective SSB station IF signal.
    Type: Grant
    Filed: October 16, 1996
    Date of Patent: February 23, 1999
    Assignee: General Research of Electronics, Inc.
    Inventor: Nobuaki Yokoyama
  • Patent number: 5841814
    Abstract: A radio frequency (rf) receiver adapted to receive a number of different digitally modulated rf input signals such as quadrature amplitude modulated (QAM) and vestigial side band (VSB) rf input signals includes circuitry for down converting the rf input signals to an intermediate frequency (IF) range having a center frequency fc2 and a bandwidth of Bhz and converter circuitry for sampling the IF signals and then producing corresponding baseband signals. In a preferred embodiment, the intermediate frequency signals are applied to a sample and hold circuit which is sampled at a frequency fs and whose output is coupled via a low pass filter to an analog-to-digital converter whose output is then applied to a Hilbert filter for demodulating the sampled signals and producing baseband signals. In-phase (I) and quadrature (Q) signals are produced whose phase and amplitude are not a function of different components and their tolerance of different conduction paths, as in the prior art.
    Type: Grant
    Filed: October 17, 1995
    Date of Patent: November 24, 1998
    Assignee: Paradyne Corporation
    Inventor: Robert L. Cupo
  • Patent number: 5835532
    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 (318). Signals produced by the multiplication are subtractively combined (320) to produce an output signal representing a carrier phase error.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: November 10, 1998
    Assignee: RCA Thomson Licensing Corporation
    Inventors: Christopher Hugh Strolle, Steven Todd Jaffe
  • Patent number: 5805242
    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.
    Type: Grant
    Filed: September 6, 1996
    Date of Patent: September 8, 1998
    Assignee: Thomson Consumer Electronics, Inc.
    Inventors: Christopher Hugh Strolle, Steven Todd Jaffe
  • Patent number: 5802461
    Abstract: Apparatus and method (10) for recovering timing information from a vestigial sideband (VSB) modulated signal generate a left hand component signal and a right hand component signal from the received signal, and filters B.sub.1 (f) and B.sub.r (f) (12, 14) filter the left hand and right hand component signals respectively. The filtered signals are then multiplied together without taking the complex conjugate of either signal, as in band edge component maximization (BECM). The generated output signal may be used in a feedback loop to regulate the sample rate of an analog to digital converter (32).
    Type: Grant
    Filed: September 16, 1996
    Date of Patent: September 1, 1998
    Assignee: Texas Instruments Incorporated
    Inventor: Alan Gatherer
  • Patent number: 5757861
    Abstract: An error detecting and correcting apparatus incorporated in a trellis decoder to compensate effects of 180.degree. phase errors of a transmitted N-level VSB (Vestigial Sideband) signal in a GA (Grand Alliance) HDTV (High Definition Television) receiver, the transmitted signal including a transmitted reference signal and a transmitted data signal, the decoder including an error detector for comparing a predetermined reference signal with the transmitted reference signal to provide an error signal denoting the presence or absence a 180.degree. phase error, a phase corrector for inverting the sign of the transmitted data signal to provide an inverted transmitted data signal, a switch for selectively providing the transmitted data signal or the inverted transmitted data signal in response to the error signal, and a trellis decoder for decoding the transmitted data signal or the inverted data signal provided by the switch.
    Type: Grant
    Filed: November 13, 1995
    Date of Patent: May 26, 1998
    Assignee: Daewoo Electronics Co., Ltd.
    Inventor: Yong-Hee Lim
  • Patent number: 5699011
    Abstract: A DC offset measurement and compensation circuit includes a switch arrangement for establishing a zero carrier condition in the circuit. The circuit output is integrated to develop any DC offsets, which are converted to analog form and subtracted from the signal output. A reference may also be subtracted to establish a base digital level for the output.
    Type: Grant
    Filed: August 2, 1996
    Date of Patent: December 16, 1997
    Assignee: Zenith Electronics Corporation
    Inventor: Gary J. Sgrignoli
  • Patent number: 5675283
    Abstract: A polarity detection circuit for an FPLL demodulated signal including a small DC pilot recovers the DC pilot by determining the DC levels of the demodulated output signals both with and without the DC pilot. A zero carrier condition is created for determining the DC level of the output signal without the DC pilot. The two DC levels are subtracted and limited and the polarity of the recovered DC pilot is used to control the operation of a polarity inverter to assure that the output signal has a desired polarity.
    Type: Grant
    Filed: August 2, 1996
    Date of Patent: October 7, 1997
    Assignee: Zenith Electronics Corporation
    Inventor: Gary J. Sgrignoli
  • Patent number: 5675284
    Abstract: A biphase stable FPLL includes a polarity determination circuit that ascertains the lockup phase of the FPLL based upon the polarity of the pilot in the digital signal. A frequency lock indicator circuit determines from the recovered pilot when frequency lock has occurred and the polarity determination circuit is responsive thereto for inverting the phase of the incoming signal (or alternatively, of the outgoing signal) as determined in order to supply an output signal of predetermined polarity. The frequency lock indicator consists of a zero crossings detector and a latch that is sampled for a time period. The zero crossings detector is a delay and an exclusive OR gate. An optional confidence counter may be used with the latch to determine when frequency lock has occurred to provide the lock indicator signal.
    Type: Grant
    Filed: August 2, 1996
    Date of Patent: October 7, 1997
    Assignee: Zenith Electronics Corporation
    Inventor: Gary J. Sgrignoli
  • Patent number: 5673293
    Abstract: Method and apparatus for providing a QAM, a VSB, and a joint QAM/VSB demodulator are described. The describe demodulators are designed to minimize the amount of duplicated circuitry required to implement a joint QAM/VSB demodulator capable of performing the functions of the disclosed individual QAM and VSB demodulators. All digital architectures are used for each of the described demodulators to facilitate their combination into the described joint VSB/QAM demodulator. The described demodulators are suitable for demodulating, e.g, advanced or high definition television signals modulated using QAM or VSB modulation techniques.
    Type: Grant
    Filed: September 8, 1994
    Date of Patent: September 30, 1997
    Assignee: Hitachi America, Ltd.
    Inventors: Carl G. Scarpa, Joshua L. Koslov, Frank A. Lane
  • Patent number: 5668498
    Abstract: A biphase stable FPLL includes a polarity determination circuit that ascertains the lockup phase of the FPLL based upon the polarity of the pilot in the digital signal. A frequency lock circuit also determines from the recovered pilot when frequency lock has occurred and the polarity determination circuit is responsive thereto for inverting the phase of the incoming, or alternatively, of the outgoing signal, as determined in order to supply an output signal of predetermined polarity.
    Type: Grant
    Filed: May 13, 1996
    Date of Patent: September 16, 1997
    Assignee: Zenith Electronics Corporation
    Inventor: Gary J. Sgrignoli
  • Patent number: 5479137
    Abstract: An oscillator, constructed partially within the confines of a monolithic integrated circuit, includes a differential-input, differential-output, differential amplifier within the monolithic integrated circuit. First and second resistive potential dividers located within the monolithic integrated circuit respectively divide the potentials appearing at the first and second output terminals of the differential amplifier in a predetermined ratio for respective application to the first and second input terminals of the differential amplifier, thereby respectively completing first and second direct-coupled regenerative feedback connections. An inductor located outside the monolithic integrated circuit is connected between the first and second input terminals of the differential amplifier and is anti-resonated by one or more capacitors, which may be located inside or outside the monolithic integrated circuit.
    Type: Grant
    Filed: December 14, 1993
    Date of Patent: December 26, 1995
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Jack R. Harford
  • Patent number: 5168215
    Abstract: An apparatus and method for measuring the frequencies of a pair of signals simultaneously present in a composite signal, comprising the steps of includes components for squaring the composite signal, filtering the squared signal for separating a first pass band and a higher frequency second pass band, instantaneously measuring the frequencies of the first and second pass bands and determining the individual frequencies of the pair of signals from the measured frequencies of the first and second pass bands.
    Type: Grant
    Filed: November 15, 1991
    Date of Patent: December 1, 1992
    Assignee: Lockheed Sanders, Inc.
    Inventor: Dean C. Puzzo
  • Patent number: 4370676
    Abstract: A synchronous detector for detecting an information signal modulated onto a carrier, such as a video IF signal, is disclosed in which there are provided a circuit for supplying the modulated information signal in the form of a vestigial sideband signal, a filter circuit coupled to the supplying circuit which includes a tuning circuit tuned to the frequency of the carrier on which the information signal is modulated, an emitter follower circuit connected to the output of the filter circuit, a limiter circuit connected to the filter circuit, for producing a switching carrier, and a multiplier having first and second input terminals coupled to the output of the limiter circuit and to the supplying circuit, for multiplying the modulated information signal and the switching carrier to obtain said information signal.
    Type: Grant
    Filed: June 26, 1981
    Date of Patent: January 25, 1983
    Assignee: Sony Corporation
    Inventors: Masayuki Hongu, Shigeru Omuro, Hiroyuki Kita, Masaharu Tokuhara
  • Patent number: 4312064
    Abstract: A communication transmission system includes one or more modulated carrier communication channels in which a receiver has a modified vestigial side band filter for eliminating phase cancellation. Accurate design of the modified vestigial side band filters at the receivers, further reduces susceptibility to frequency drift caused by component aging and component response to environmental changes. The system has particular utility in multiple channel carrier telephone communication systems which utilize limited available band width for providing a maximum number of communication channels over an extended length communication line.
    Type: Grant
    Filed: January 25, 1980
    Date of Patent: January 19, 1982
    Assignee: The Anaconda Company
    Inventors: Stephen M. Bench, Paul H. Thibodeau, Guy M. Campbell, Theodore M. Stump
  • Patent number: 4292594
    Abstract: The invention relates to a method of regenerating the modulation carrier wave of an original modulated signal (SL) which has symmetrical frequency components about the carrier. A phase discriminator (D1) which receives two image signals (SL, S11) of the original signal controls the frequency of a local oscillator (OL), the frequency spectrum of one of the image signals being inverted with respect to that of the original signal and the difference in frequencies between these two image signals being twice that between the local carrier and the carrier of the original signal. Application to the synchronous demodulation of a television signal.
    Type: Grant
    Filed: August 21, 1979
    Date of Patent: September 29, 1981
    Assignee: Compagnie Industrielle des Telecommunications Cit-Alcatel
    Inventors: Jacques David, Hubert Mionet