Vestigial Sideband Patents (Class 455/204)
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Patent number: 8861581Abstract: 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: GrantFiled: April 5, 2011Date of Patent: October 14, 2014Assignee: Samsung Electronics Co., Ltd.Inventors: DoHan Kim, Sergey Zhidkov, Beom kon Kim
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Patent number: 8699600Abstract: 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: GrantFiled: February 23, 2011Date of Patent: April 15, 2014Assignee: K-Tech Telecommunications, IncInventor: Steve Kuh
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Patent number: 8364179Abstract: 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: GrantFiled: March 31, 2010Date of Patent: January 29, 2013Assignee: Provigent Ltd.Inventors: Ehud Ashkenazi, Jonathan Friedmann
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Patent number: 8340025Abstract: 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: GrantFiled: May 27, 2010Date of Patent: December 25, 2012Assignee: Research In Motion LimitedInventor: Matthias Wandel
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Patent number: 8300569Abstract: 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: GrantFiled: February 27, 2012Date of Patent: October 30, 2012Assignee: LG Electronics Inc.Inventors: Jae Hyung Song, In Hwan Choi, Jong Yeul Suh, Jin Pil Kim, Chul Soo Lee
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Patent number: 8284089Abstract: 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: GrantFiled: December 9, 2010Date of Patent: October 9, 2012Assignee: STMicroelectronics Asia Pacific Pte LtdInventor: Yannick Guedon
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Patent number: 8175193Abstract: 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: GrantFiled: March 28, 2008Date of Patent: May 8, 2012Assignee: LG Electronics Inc.Inventor: Jae Hyung Kim
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Patent number: 8150325Abstract: 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: GrantFiled: June 12, 2008Date of Patent: April 3, 2012Assignee: The United States of America as represented by the Secretary of the NavyInventor: Brad A. Prichard
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Patent number: 8130873Abstract: 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: GrantFiled: August 9, 2005Date of Patent: March 6, 2012Assignee: Samsung Electronics Co., Ltd.Inventor: Dong-hoon Lee
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Patent number: 7738616Abstract: 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: GrantFiled: April 16, 2002Date of Patent: June 15, 2010Assignee: Thomson LicensingInventor: Ivonete Markman
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Patent number: 7634029Abstract: 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: GrantFiled: August 23, 2005Date of Patent: December 15, 2009Assignee: Samsung Electronics Co., LtdInventor: Dong-hoon Lee
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Publication number: 20090258620Abstract: 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: ApplicationFiled: December 24, 2007Publication date: October 15, 2009Inventor: Jae Kil Jung
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Publication number: 20090227221Abstract: 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: ApplicationFiled: March 6, 2008Publication date: September 10, 2009Applicant: LEGEND SILICON CORP.Inventors: LIN YANG, QIN LIU
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Publication number: 20090055865Abstract: 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: ApplicationFiled: August 25, 2008Publication date: February 26, 2009Inventors: Hui Sang Yoo, In Hwan Choi, Chul Soo Lee, Jae Hyung Song, Min Sung Kwak
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Publication number: 20090046815Abstract: 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: ApplicationFiled: July 2, 2008Publication date: February 19, 2009Inventors: Hyen O. Oh, In Hwan Choi, Kook Yeon Kwak, Byoung Gill Kim, Won Gyu Song, Jin Woo Kim, Hyoung Gon Lee
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Patent number: 7474990Abstract: 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: GrantFiled: September 29, 2006Date of Patent: January 6, 2009Assignee: Techwell, Inc.Inventor: Joon Tae Kim
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Patent number: 7450658Abstract: 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: GrantFiled: August 2, 2007Date of Patent: November 11, 2008Assignee: Industrial Technology Research InstituteInventors: Jiann-An Tsai, Shih-Kai Lee, Chang-Lung Hsiao
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Patent number: 7433417Abstract: 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: GrantFiled: February 17, 2003Date of Patent: October 7, 2008Assignee: NXP B.V.Inventors: Wouter Joos Tirry, Ludovic Albert Jozef Van Paepegem
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Patent number: 7349354Abstract: 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: GrantFiled: November 20, 2002Date of Patent: March 25, 2008Assignee: LG Electronics Inc.Inventor: Sung Hyun Yun
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Patent number: 7330513Abstract: 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: GrantFiled: June 17, 2004Date of Patent: February 12, 2008Assignee: Industrial Technology Research InstituteInventors: Jiann-An Tsai, Shih-Kai Lee, Chang-Lung Hsiao
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Patent number: 7272197Abstract: 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: GrantFiled: September 30, 2003Date of Patent: September 18, 2007Assignee: LG Electronics Inc.Inventor: Yong Suk Hwang
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Patent number: 7231002Abstract: 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: GrantFiled: October 14, 2003Date of Patent: June 12, 2007Assignee: LG Electronics Inc.Inventor: Yong Suk Hwang
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Patent number: 7177609Abstract: 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: GrantFiled: May 16, 2003Date of Patent: February 13, 2007Assignee: National Semiconductor CorporationInventor: Hee Wong
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Patent number: 7061977Abstract: 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: GrantFiled: September 10, 2001Date of Patent: June 13, 2006Assignee: Koninklijke Philips Electronics N.V.Inventors: Richard K. Martin, Robert C. Williamson, William A. Sethares
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Patent number: 7016659Abstract: 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: GrantFiled: June 12, 2003Date of Patent: March 21, 2006Inventors: Michael L. Dorrough, Dennis Robert Lee, Alfred Edward Parker, Richard Williamson Burden
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Patent number: 7010269Abstract: 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: GrantFiled: May 7, 2001Date of Patent: March 7, 2006Assignee: Koninklijke Philips Electronics N.V.Inventors: Joseph Patrick Meehan, David Koo
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Patent number: 6950481Abstract: 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: GrantFiled: June 13, 2003Date of Patent: September 27, 2005Assignee: Samsung Electronics Co., Ltd.Inventor: Allen LeRoy Limberg
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Patent number: 6891898Abstract: 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: GrantFiled: October 23, 2002Date of Patent: May 10, 2005Assignee: iBiquity Digital CorporationInventors: Paul James Peyla, Joseph Bertram Bronder
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Publication number: 20040246072Abstract: 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: ApplicationFiled: June 2, 2004Publication date: December 9, 2004Inventors: Seiji Hidaka, Shin Abe
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Publication number: 20030078023Abstract: 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: ApplicationFiled: October 23, 2001Publication date: April 24, 2003Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.Inventors: Krishnamurthy Vaidyanathan, Geoffrey F. Burns
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Patent number: 6539063Abstract: 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: GrantFiled: February 18, 1999Date of Patent: March 25, 2003Assignee: Ibiquity Digital CorporationInventors: Paul James Peyla, Joseph Bertram Bronder
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Patent number: 6418164Abstract: 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: GrantFiled: January 14, 1999Date of Patent: July 9, 2002Assignee: Nxtwave Communications, Inc.Inventors: Thomas J Endres, Samir N Hulyalkar, Christopher H Strolle, Troy A Schaffer
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Patent number: 6351293Abstract: 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: GrantFiled: July 13, 1998Date of Patent: February 26, 2002Assignees: Sarnoff Corporation, Motorola Inc.Inventor: Randall Bret Perlow
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Patent number: 6154505Abstract: 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: GrantFiled: December 19, 1997Date of Patent: November 28, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takaaki Konishi, Kazuya Ueda, Hisaya Kato, Kunio Ninomiya
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Patent number: 5875389Abstract: 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: GrantFiled: October 16, 1996Date of Patent: February 23, 1999Assignee: General Research of Electronics, Inc.Inventor: Nobuaki Yokoyama
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Patent number: 5841814Abstract: 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: GrantFiled: October 17, 1995Date of Patent: November 24, 1998Assignee: Paradyne CorporationInventor: Robert L. Cupo
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Patent number: 5835532Abstract: 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: GrantFiled: September 5, 1996Date of Patent: November 10, 1998Assignee: RCA Thomson Licensing CorporationInventors: Christopher Hugh Strolle, Steven Todd Jaffe
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Patent number: 5805242Abstract: 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: GrantFiled: September 6, 1996Date of Patent: September 8, 1998Assignee: Thomson Consumer Electronics, Inc.Inventors: Christopher Hugh Strolle, Steven Todd Jaffe
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Patent number: 5802461Abstract: 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: GrantFiled: September 16, 1996Date of Patent: September 1, 1998Assignee: Texas Instruments IncorporatedInventor: Alan Gatherer
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Patent number: 5757861Abstract: 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: GrantFiled: November 13, 1995Date of Patent: May 26, 1998Assignee: Daewoo Electronics Co., Ltd.Inventor: Yong-Hee Lim
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Patent number: 5699011Abstract: 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: GrantFiled: August 2, 1996Date of Patent: December 16, 1997Assignee: Zenith Electronics CorporationInventor: Gary J. Sgrignoli
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Patent number: 5675284Abstract: 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: GrantFiled: August 2, 1996Date of Patent: October 7, 1997Assignee: Zenith Electronics CorporationInventor: Gary J. Sgrignoli
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Patent number: 5675283Abstract: 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: GrantFiled: August 2, 1996Date of Patent: October 7, 1997Assignee: Zenith Electronics CorporationInventor: Gary J. Sgrignoli
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Patent number: 5673293Abstract: 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: GrantFiled: September 8, 1994Date of Patent: September 30, 1997Assignee: Hitachi America, Ltd.Inventors: Carl G. Scarpa, Joshua L. Koslov, Frank A. Lane
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Patent number: 5668498Abstract: 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: GrantFiled: May 13, 1996Date of Patent: September 16, 1997Assignee: Zenith Electronics CorporationInventor: Gary J. Sgrignoli
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Patent number: 5479137Abstract: 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: GrantFiled: December 14, 1993Date of Patent: December 26, 1995Assignee: Samsung Electronics Co., Ltd.Inventor: Jack R. Harford
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Patent number: 5168215Abstract: 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: GrantFiled: November 15, 1991Date of Patent: December 1, 1992Assignee: Lockheed Sanders, Inc.Inventor: Dean C. Puzzo
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Patent number: 4370676Abstract: 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: GrantFiled: June 26, 1981Date of Patent: January 25, 1983Assignee: Sony CorporationInventors: Masayuki Hongu, Shigeru Omuro, Hiroyuki Kita, Masaharu Tokuhara
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Patent number: 4312064Abstract: 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: GrantFiled: January 25, 1980Date of Patent: January 19, 1982Assignee: The Anaconda CompanyInventors: Stephen M. Bench, Paul H. Thibodeau, Guy M. Campbell, Theodore M. Stump
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Patent number: 4292594Abstract: 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: GrantFiled: August 21, 1979Date of Patent: September 29, 1981Assignee: Compagnie Industrielle des Telecommunications Cit-AlcatelInventors: Jacques David, Hubert Mionet