Noise Or Distortion Reduction Patents (Class 375/254)
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Patent number: 7546137Abstract: A method for use in a RFID reader, the method comprising providing an output signal from an amplifier of a transmitter, attenuating the output signal via a step attenuator, detecting and comparing the attenuated output signal to a reference value, and adjusting power to the amplifier until the attenuated output signal is substantially equal to the reference value. The attenuated output signal drives a local oscillator signal of a receiver thereby canceling noise generated by the transmitter in the receiver.Type: GrantFiled: February 27, 2006Date of Patent: June 9, 2009Assignee: Sirit Technologies Inc.Inventors: Loek J. D'Hont, Bernard Barink
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Patent number: 7535973Abstract: A method and apparatus for correcting the delay between the phase and the envelope of a digital signal are described. In particular, the application of this correction in digital broadcasting transmitters is described. The present invention makes it possible to offer an alternative solution in which the use of the initial signal is not necessary. No temporal comparison with the initial signal is necessary. A subject of the invention is a method of correcting at least one parameter to be corrected pc of the envelope of a digital signal including the decomposition of the digital signal into an envelope signal and a phase signal and the determination of the corrector to be applied to the parameter of the envelope by searching for the minimum out-of-band noise powers of the signal.Type: GrantFiled: December 15, 2003Date of Patent: May 19, 2009Assignee: ThalesInventor: Bruno Clotteau
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Patent number: 7535962Abstract: A method and apparatus are provided that allow exploitation of the common mode characteristics of a differential transmission network to provide an additional data signal. Signal (MODE) represents either a binary signal or a multi-valued signal to allow signaling of one or more bits of information. The signaling occurs through the variation of the common mode voltage in transmitters (300 and 400) and is detected using differential receiver (600). One embodiment is presented that achieves signaling of an extended run length data sequence to allow continued transmitter/receiver synchronization throughout the transmission of the sequence. In an alternate embodiment, a separate data path is provided to signal the extended run length sequence when a common mode signaling path is not available.Type: GrantFiled: April 2, 2008Date of Patent: May 19, 2009Assignee: Xilinx, Inc.Inventor: William C. Black
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Patent number: 7529331Abstract: A wobble clock generator with a protective mechanism that can avoid interference generated from a phase-modulated wobble signal. The wobble clock generator has an arithmetic/logic circuit and a phase-locked loop. The arithmetic/logic circuit calculates a period count value by counting a period of a wobble signal according to a reference clock, and compares an average value with the period count value for outputting a control signal. The phase-locked loop is electrically connected to the arithmetic/logic circuit for generating a wobble clock according to the control signal and the wobble signal. When the control signal corresponds to a first logic level, the phase-locked loop compares the wobble signal with the wobble clock to drive the wobble clock to be synchronized with the wobble signal. When the control signal corresponds to a second logic level, the phase-locked loop holds the wobble signal without synchronizing the wobble clock with the wobble signal.Type: GrantFiled: April 7, 2004Date of Patent: May 5, 2009Inventor: Yuan-Kun Hsiao
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Patent number: 7529176Abstract: The present invention relates to a method for determining a transmit PSD over a remotely-deployed line, which method comprising the steps of: modeling a first far-end crosstalk originating from the line and coupling into a centrally-deployed victim neighboring line, modeling a second far-end crosstalk originating from a further centrally-deployed neighboring line and coupling into the victim neighboring line, determining the transmit PSD from the first modeled far-end crosstalk and the second modeled far-end crosstalk. A method according to the invention further comprises the steps of: expressing the transmit PSD as a function of a line parameter characterizing a line segment of the further neighboring line, carrying out channel measurements of a spare line that connects the central location to the remote location, and that shares common transmission characteristics with the line segment, estimating from said channel measurements a value of the line parameter, determining therefrom the transmit PSD.Type: GrantFiled: December 19, 2005Date of Patent: May 5, 2009Assignee: AlcatelInventors: Jan Sylvia Verlinden, Etienne André Hubert Van Den Bogaert, Geert Bert Maarten Ysebaert
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Publication number: 20090103595Abstract: A pulse signal transmitting/receiving device is provided. The device includes a signal generating module for generating a transmitting signal including an amplitude-modulated chirp signal, and a reference signal including a chirp signal having a frequency that changes similarly to that of the transmitting signal, a transmitting module for transmitting a pulse having approximately the same waveform as that of the transmitting signal, a receiving module for receiving an echo signal that is the transmitting pulse reflected from a detection target object, a compensating module for extending a dynamic range of the echo signal received by the receiving module, and a pulse compressing module for outputting a pulse-compressed echo signal, wherein the pulse compression is performed by a correlation calculation between the echo signal having the dynamic range extended by the compensating module, and the reference signal.Type: ApplicationFiled: September 10, 2008Publication date: April 23, 2009Applicant: Furuno Electric Co., Ltd.Inventors: Kenichi Watanabe, Yasunobu Asada, Shinji Ogawa
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Patent number: 7522661Abstract: A method of producing of a two-dimensional probability density function eye diagram and Bit Error Rate eye arrays generates a two-dimensional PDF array of a correlated waveform record of a data pattern under test which is convolved with a two-dimensional probability density function (PDF) array of the uncorrelated jitter and noise in the data pattern under test. The resulting aggregate two dimensional PDF array of the correlated waveform record pattern with uncorrelated jitter and noise is divided into unit intervals and the unit intervals are summed to generated a two-dimensional PDF eye diagram array. The two-dimensional PDF eye diagram is processed to generate a two-dimensional Bit Error Rate eye array.Type: GrantFiled: July 25, 2005Date of Patent: April 21, 2009Assignee: Tektronix, Inc.Inventors: Michael A. Nelson, John E. Carlson
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Patent number: 7499509Abstract: An apparatus for compensating nonlinearly distorted multicarrier signals, a multicarrier signal receiver using the same, and a method therefor are provided, where the apparatus for compensating multicarrier signals and the multicarrier signal receiver using the apparatus extract parameter information on the HPA mode from the received signal so that nonlinear distortion of the received multicarrier signal is compensated for even though an accurate transfer function of a high power amplifier (HPA) is not known and side information or a special training signal is not transmitted when a signal is transmitted, such that nonlinearly distorted multicarrier signals such as OFDM signals transmitted by an HPA having a variety of transfer functions can be adaptively compensated and therefore a demodulated signal with an improved symbol error rate (SER) can be obtained.Type: GrantFiled: September 14, 2004Date of Patent: March 3, 2009Assignee: Samsung Electronics Co., Ltd.Inventor: Sergey Zhidkov
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Patent number: 7499490Abstract: Methods and apparatus to encode message input symbols in accordance with an accumulate-repeat-accumulate code with repetition three or four are disclosed. Block circulant matrices are used. A first method and apparatus make use of the block-circulant structure of the parity check matrix. A second method and apparatus use block-circulant generator matrices.Type: GrantFiled: June 24, 2005Date of Patent: March 3, 2009Assignees: California Institute of Technology, The Regents of the University of CaliforniaInventors: Dariush Divsalar, Aliazam Abbasfar, Christopher R. Jones, Samuel J. Dolinar, Jeremy C. Thorpe, Kenneth S. Andrews, Kung Yao
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Patent number: 7496340Abstract: A system and method are provided for calibrating for an I/Q mismatch of a direct conversion receiver based on a random signal having a two-dimensional I versus Q trajectory, such as radio frequency (RF) noise. In general, the random signal is received and downconverted to a quadrature baseband signal having an in-phase component and a quadrature component. The variance of the in-phase component, the variance of the quadrature component, and the covariance of the in-phase component with the quadrature component are computed based on samples of the quadrature baseband signal. A correction matrix used to compensate for the I/Q mismatch of the receiver and/or I/Q mismatch including a gain mismatch and a phase mismatch of the receiver is then computed based on the variance of the in-phase component, the variance of the quadrature component, and the covariance of the in-phase component with the quadrature component.Type: GrantFiled: June 2, 2005Date of Patent: February 24, 2009Assignee: RF Micro Devices, Inc.Inventors: Jesse E. Chen, Patrick Vandenameele, Steven Thoen, Alex Zenkin, Pengfei Zhang, Peter Hanson, Dmitri Varsanofiev, Peter Cnudde
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Patent number: 7496164Abstract: A system and method for interference cancellation is provided to cancel/greatly reduce the interference of a wireless network. The interferers are separated from a desired signal using independent component analysis by hypothesizing the transmitting sequence. An optional whitening filter is used after the signal separation to improve the signal conditioning. The separated signal is processed by a second pass channel estimation to improve the signal channel estimation and is fed to a Maximum Likelihood Sequence Estimation (MLSE) algorithm, such as a Viterbi algorithm, for signal detection.Type: GrantFiled: May 3, 2004Date of Patent: February 24, 2009Assignee: AT&T Mobility II LLCInventor: Ayman A. Mostafa
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Patent number: 7492813Abstract: A startup protocol is provided for use in a communications system having a communications line with a master transceiver at a first end and a slave transceiver at a second end, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer all converging at startup of the system. The operation of the startup protocol is partitioned into stages. The first stage includes the step of converging the equalizer and the timing recovery system of the slave while converging the noise reduction system of the master. Upon completion of the first stage the protocol enters a second stage which includes the step of converging the equalizer and the timing recovery system of the master, converging the noise reduction system of the slave, freezing the timing recovery system of the slave, and resetting the noise reduction system of the master.Type: GrantFiled: January 29, 2004Date of Patent: February 17, 2009Assignee: Broadcom CorporationInventor: Oscar E. Agazzi
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Patent number: 7489747Abstract: A decision directed flicker noise canceller for reducing flicker noise in a modulated input signal according to an embodiment of the present invention includes a decision circuit, a conversion circuit, first and second adders and a filter. The decision circuit provides signal decisions based on the input signal. The conversion circuit provides selected signal values based on the signal decisions. The first adder subtracts the selected signal values from signals based on the input signal to provide a flicker noise estimate. The filter receives and filters the flicker noise estimate and the second adder subtracts the filtered flicker noise estimate from the input signal and provides a corrected input signal. In a feedback configuration, the second adder is located in a feedback position before the decision circuit in the signal processing path. In a feed-forward configuration, the second adder is located in a feed-forward position after the decision circuit.Type: GrantFiled: February 13, 2004Date of Patent: February 10, 2009Assignee: Xocyst Transfer AG L.L.C.Inventors: Mark A. Webster, Alex C. Yeh, Keith R. Baldwin
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Patent number: 7484139Abstract: An amplifier (1) adapted to receive an input signal and to generate an output signal at an amplifier output (7) according to the input signal, the amplifier (1) comprising: a feedback circuit arranged to provide a feedback signal indicative of the output signal; an error signal generating circuit (12, 44) arranged to receive the feedback signal and generate a digital error signal according to the feedback signal; and an output signal generating circuit arranged to generate the output signal and to receive the digital error signal and to adjust the output signal according to the digital error signal; the amplifier (1) further comprising: a fault detection circuit (50) arranged to receive the digital error signal and to determine the presence or absence of a fault condition at the amplifier output (7) according to the digital error signal and to provide a signal (54) indicative of the presence or absence of the fault condition.Type: GrantFiled: December 22, 2005Date of Patent: January 27, 2009Assignee: Zetex Semiconductors PlcInventor: Robert Watts
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Patent number: 7469020Abstract: Systems, methods, and apparatus for reducing dynamic range requirements of a power amplifier in a wireless device are provided. An exemplary method may include modulating a symbol stream to generate a modulated waveform. The exemplary method may further include generating at least one pulse having a peak aligned with an anticipated position of a peak or a null corresponding to the modulated waveform, where the anticipated position of the a peak or the null corresponding to modulated waveform may be determined by detecting a transition in a phase or an amplitude of the modulated waveform.Type: GrantFiled: April 26, 2005Date of Patent: December 23, 2008Assignee: Freescale Semiconductor, Inc.Inventors: James Wesley McCoy, Kevin B. Traylor
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Patent number: 7460832Abstract: Methods and apparatuses for minimizing co-channel interference in communications systems are disclosed. A method in accordance with the present invention comprises scrambling a first frame using a first scrambling code, attaching a first header to the first frame to create the first signal, scrambling a second frame using a second scrambling code, attaching a second header to the second frame to create the second signal, and transmitting the first signal and the second signal over different channels of the communication system.Type: GrantFiled: April 11, 2005Date of Patent: December 2, 2008Assignee: The DIRECTV Group, Inc.Inventors: Lin-Nan Lee, Feng-Wen Sun, Adam Von Ancken, Joseph Santoru, Ernest C. Chen, Shamik Maitra, Dennis Lai, Guangcai Zhou, Tung-Sheng Lin
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Patent number: 7453963Abstract: A common problem in audio processing is that a useful signal is disturbed by one or more sinusoidal noises that should be suppressed. One embodiment of the invention provides a method of canceling a sinusoidal disturbance of unknown frequency in a disturbed useful signal. The method comprises the steps of estimating parameters of the sinusoidal disturbance including amplitude, phase and frequency; generating a reference signal on the basis of the estimated parameters; and subtracting the reference signal from the disturbed useful signal. According to one embodiment of the present invention, the estimation is performed by an Extended Kalman filter.Type: GrantFiled: May 25, 2005Date of Patent: November 18, 2008Assignee: Honda Research Institute Europe GmbHInventors: Frank Joublin, Martin Heckmann, Björn Schölling
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Patent number: 7443916Abstract: A method, system and apparatus for reliable multicarrier communication in the presence of periodic impulsive interference is disclosed. A power level of noise in a signal is determined. An impulse noise in the signal is detected. A gain factor associated with the impulse noise is determined and applied to the noise power of the signal to calculate an equivalent noise power. In one aspect, the equivalent noise power is used to determine a signal-noise-ratio.Type: GrantFiled: November 24, 2003Date of Patent: October 28, 2008Assignee: 2Wire, Inc.Inventors: Hossein Sedarat, Ben Miller
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Patent number: 7440508Abstract: A a system for allocating subcarriers to subscribers, comprising a subcarriers allocation controller, connected to a subcarrier modulation unit in a transmitter and to a subcarrier demodulation unit in a receiver for setting a group of subcarriers to be used therein. The transmitter and the receiver are part of the transceiver and subcarriers allocation is made according to a Reed-Solomon code. In a multicarrier system, a method for allocating subcarriers to subscribers, comprising: A. keep a table of R-S codes for frequency group allocation to base stations; B. assign one set of subcarriers based on R-S codes to a base station; C. assign other sets of subcarriers based on R-S codes to other base stations in such a way that adjacent base stations have different R-S codes.Type: GrantFiled: November 25, 2005Date of Patent: October 21, 2008Inventor: Zion Hadad
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Patent number: 7424332Abstract: An audio signal processing apparatus includes first and second tables. The first table has coefficients. The second table has corrective values for correction of the coefficients in the first table. The corrective values are assigned to different sample numbers in at least two successive half-wave signal portions. Detection is made as to a sample number in a corrected-object half-wave portion of a digital audio signal and a sample number in a half-wave portion of the digital audio signal which precedes the corrected-object half-wave portion. The coefficients in the first table are corrected into correction-resultant coefficients in response to the detected sample numbers while the corrective values in the second table are used. Samples in the corrected-object half-wave portion of the digital audio signal are corrected in response to the correction-resultant coefficients.Type: GrantFiled: November 10, 2003Date of Patent: September 9, 2008Assignee: Victor Company of Japan, Ltd.Inventors: Kazuhito Okayama, Toshiharu Kuwaoka, Isao Hijikata, Ryouichi Nagata, Haruyuki Mori
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Patent number: 7412209Abstract: Methods and apparatuses for minimizing co-channel interference in communications systems are disclosed. A method in accordance with the present invention comprises shifting a characteristic of the first signal with respect to a like characteristic of the second signal to mitigate co-channel interference, and transmitting the first signal and the second signal over different channels of the communication system.Type: GrantFiled: April 11, 2005Date of Patent: August 12, 2008Assignee: The DIRECTV Group, Inc.Inventors: Joseph Santoru, Ernest C. Chen, Shamik Maitra, Dennis Lai, Guangcai Zhou, Tung-Sheng Lin
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Publication number: 20080159411Abstract: A controller and associated methods. A controller has an input for a controlled variable; a proportional term; an integral term; and a predictive term. The predictive term has an error-predictive subterm including at least a past value of an error; and a command-predictive subterm including at least one past value of a control command value; and an output. The controller can apply the predictive term and at least one of the proportional term and integral term to generate a command for the output. A method for controlling a process variable is also provided including applying a predictive term having an error-predictive subterm that includes at least a past value of an error and a command-predictive subterm that has at least a past value of a control command. The method further includes the step of generating a command based on the results of the applying the terms.Type: ApplicationFiled: January 2, 2007Publication date: July 3, 2008Applicant: Neuroblast, Inc.Inventors: Francisco J. Ayala, Carl H. Sturmer
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Patent number: 7391713Abstract: A technique for Crest Factor reduction of multi-carrier signals using phase rotation is described. The multi-carrier signal could be in digital baseband, analog baseband, or analog RF (radio frequency). The multi-carrier signal is converted to individual baseband representatives before each individual baseband signal being phase rotated according to an algorithm which maintains the crest factor to a pre-defined value. The algorithm uses a deterministic phase rotation technique and each phase rotated baseband signals will be individually filtered to remove the unwanted signals. The phase rotated and filtered baseband signals are then up converted and combined to reconstruct the multi-carrier signal. The crest factor reduction is limited by the in band distortion introduced to each individual signal.Type: GrantFiled: December 30, 2003Date of Patent: June 24, 2008Inventor: Kiomars Anvari
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Patent number: 7372916Abstract: Digital signals are transmitted on a bus at given instants selectively in a non-encoded format and an encoded format. The decision whether to transmit the signals in non-encoded format or in encoded format is taken in part, based on a comparison of the signal to be transmitted on the bus for an instant of the aforesaid given instants with the signal transmitter on the bus for the preceding instant, so as to minimize switching activity on the bus.Type: GrantFiled: September 25, 2003Date of Patent: May 13, 2008Assignee: STMicroelectronics S.r.lInventors: Francesco Pappalardo, Giuseppe Notarangelo
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Patent number: 7359442Abstract: A method and system for estimating a time shift required for symbol synchronization in a block oriented digital communication systems such as an orthogonal frequency division multiplexing (OFDM) or a discrete multi-tone (DMT) data transmission system. The method uses an N/d inverse discrete Fourier transform (IDFT), where N is a sample number and d is a decimation factor, or alternatively an N/(2d) inverse fast Fourier transform (IFFT) for a real received signal or an N/d IDFT for a complex received signal.Type: GrantFiled: August 24, 2006Date of Patent: April 15, 2008Assignee: Intellon CorporationInventors: John Louis Fanson, Douglas Hamilton Taylor
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Patent number: 7359437Abstract: A communication system including a transmitter, a receiver, and a serial link, in which encoded data (e.g., encoded video data and encoded auxiliary data) are transmitted from the transmitter to the receiver. The serial link can but need not be a TMDS or TMDS-like link. In typical embodiments, alternating bursts of encoded video data and encoded auxiliary data are transmitted over each of one or more channels of the link. Other aspects of the invention are transmitters for use in encoding data for transmission over a serial link, and methods for sending encoded data over a serial link. In accordance with the invention, the data to be transmitted are encoded using a subset (sometimes referred to as a selected set of code words) of a full set of code words.Type: GrantFiled: December 24, 2001Date of Patent: April 15, 2008Assignee: Silicon Image, Inc.Inventors: Seung Ho Hwang, Jano Banks, Paul Daniel Wolf, Eric Lee, Baegin Sung, Albert M. Scalise
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Patent number: 7332930Abstract: A noise canceller circuit capable of suppressing power supply noise, produced by transition of a data signal, even in case a data signal is increased in speed. The noise canceller circuit includes an output buffer 20 for outputting a first binary signal that may undergo transition at a timing synchronized with clock signals, and a second output buffer 21 for outputting a second binary signal which has undergone transition in case the first binary signal does not undergo transition at the above timing and for outputting the second binary signal without transition in case the first binary signal has undergone transition at the above timing. The respective output circuits of the output buffers 20, 21 are the same and are constructed so that the respective power supply sources VDD and the ground GND are common to the buffer circuits. A capacitor 24 for absorbing the noise is provided across the power supply and the ground.Type: GrantFiled: April 27, 2005Date of Patent: February 19, 2008Assignee: NEC Electronics CorporationInventor: Masafumi Mitsuishi
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Patent number: 7298711Abstract: According to one exemplary embodiment, a communication device comprises a line driver, where the line driver provides an output signal. The communication device further comprises a digital echo canceller module coupled to the line driver, where the digital echo canceller module receives an echo reference signal determined by the output signal of the line driver, where the echo canceller module outputs an echo cancellation signal, and where the echo cancellation signal is capable of canceling linear and non-linear components of a composite signal. The communication device further comprises a summation module coupled to the digital echo canceller module, where the summation module receives the echo cancellation signal and the composite signal, and where the composite signal comprises a received signal and the linear and non-linear echo components. The summation module is configured to subtract the echo cancellation signal from the composite signal and to output the received signal.Type: GrantFiled: September 23, 2002Date of Patent: November 20, 2007Assignee: Mindspeed Technologies, Inc.Inventor: Michael J. Jarcy
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Patent number: 7260163Abstract: A noise blanker (40, 106) monitors and removes noise from a sampled signal by adaptive filtering (98, 150) the sampled signal to generate trained adaptive filter prediction coefficients. The sampled signal is provided as an output signal when the noise blanker is in a training mode. A noise monitor (34, 154) detects whether noise contained within the sampled signal exceeds a predetermined threshold and provides a control signal in response to the detecting. The noise blanker is placed in a prediction mode for a predetermined amount of time in response to asserting the control signal. A prediction output signal is generated using a plurality of prediction coefficients as an all-pole filter. The prediction output signal has minimal noise content.Type: GrantFiled: August 9, 2002Date of Patent: August 21, 2007Assignee: Freescale Semiconductor, Inc.Inventors: Junsong Li, Ronald Wang, Raghu G. Raj
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Patent number: 7257164Abstract: The present invention relates to Class-D amplifiers, and in particular to bit-flipping sigma-delta modulator (SDM) implementations of such amplifiers. Such amplifiers are particularly although not exclusively suitable for audio equipment such as hi-fi and personal music amplifiers. The present invention provides a bit flipping sigma delta modulator (BF SDM) having a multiple feedback loop filter structure. The modulator comprises a quantiser coupled to a bit flipping means, a look ahead quantiser to determine the next quantiser output, and a controller which determines whether to change the output of the bit flipping circuit. The modulator comprises a feedback loop arranged to add feedback from the output of the modulator to its input. The modulator comprises compensation circuit to adjust the states of the modulator in order to correct for bit flipping of the output of the quantiser. This adjusts the input to the quantiser to correspond to an input having feedback from a non bit flipped quantiser output.Type: GrantFiled: February 4, 2004Date of Patent: August 14, 2007Assignee: Wolfson Microelectronics plcInventor: Anthony J. Magrath
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Patent number: 7242725Abstract: An adaptive broadband post-distortion receiver for wireless digital communications improves performance of a wireless digital communications system. The improved performance of the system includes improved linear AM-AM and AM-PM responses approaching saturation. Indeed, the proposed adaptive broadband post-distortion receiver has an effect on attributes such as bit error rate and transmitter power efficiency and, in turn, on modulation and bandwidth. The adaptive broadband post-distortion receiver is configured with an adaptively controlled IF post-distorter located at the IF stage of the receiver. The placement of the distortion canceling function in the IF section of the receiver lends itself to broadband applications. The post-distorter is configured to cancels the distortion produced by the transmitter and receiver as it is adaptively controlled using bit error rate calculations. The distortion canceling utilizes bit error rate information that is otherwise available in the receiver.Type: GrantFiled: April 2, 2003Date of Patent: July 10, 2007Assignee: Harris Stratex Networks Operating CorporationInventors: Frank S. Matsumoto, David C. M. Pham
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Patent number: 7239657Abstract: Apparatus and a method for enhancing the interference resistance of so-called RFID systems, wherein identification messages delivered from an identification device are longer than the time for which an anticipated interference or disturbance is calculated to continue, and wherein the messages contain redundancy, such as a checksum. The messages are delivered from the identification device repetitively, and are redundancy checked. In the event of any discrepancy in the redundancy check, such as when the checksum is checked against the data content of the message and is found in disagreement, successive messages are checked bit for bit against each other. Any deviations between otherwise previously rejected messages are assumed to be due to external interference and are thus successively substituted until the redundancy check gives an accepted result, such as through the medium of a checksum check according to the so-called CRC method.Type: GrantFiled: November 1, 2000Date of Patent: July 3, 2007Assignee: Tagmaster AGInventor: Staffan Gunnarsson
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Patent number: 7236451Abstract: Dynamic Time Metered Delivery (DTMD) is a unique physical layer communication Method. DTMD uses enhanced time-based techniques to enable and control the flow of more data/Hertz through a variety of transmission media including existing and new copper phone lines, coaxial cable, fiber optic, powerline and wireless RF, Optical and Acoustic, to and from a comprehensive, multi-function customer data gateway. The system measures the transmission parameters as viewed from the “end of the line” and then sends these numerics back to the source which alters the shape of the basic signal structure such that when received at the far end, it will have maximum recognition attributes against interferers and noise. The present system and method add the adaptivity to the line conditions and set a maximum allowable data rate within the subscribed levels of performance.Type: GrantFiled: March 3, 2003Date of Patent: June 26, 2007Assignee: Telepulse Technologies CorporationInventors: Richard De Francesco, Bernard Harris, Wade Darlington, Rodney Barnhart, Kenneth Abend, Jack Starrantino, Irving Susskind, Borys Umyn
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Patent number: 7224741Abstract: A system for allocating subcarriers to subscribers, comprising a subcarriers allocation controller, connected to a subcarrier modulation unit in a transmitter and to a subcarrier demodulation unit in a receiver for setting a group of subcarriers to be used therein. The transmitter and the receiver are part of the transceiver and subcarriers allocation is made according to a Reed-Solomon code. In a multicarrier system, a method for allocating subcarriers to subscribers, comprising the steps of: A. keep a table of R-S codes for frequency group allocation to base stations; B. assign one set of subcarriers based on R-S codes to a base station; C. assign other sets of subcarriers based on R-S codes to other base stations in such a way that adjacent base stations have different R-S codes, to minimize the number of collision points therebetween.Type: GrantFiled: July 24, 2000Date of Patent: May 29, 2007Inventor: Zion Hadad
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Patent number: 7225001Abstract: The present invention advantageously provides a manner by which to further suppress noise superimposed upon an information signal without increasing distortion to the signal, e.g., speech. By distributing the noise suppression, the quality of the information signal provided to a listener is improved. In one embodiment, a first noise suppressor is employed at the transmitter to suppress noise superimposed upon an information signal prior to its transmission by the transmitter, and a second noise suppressor is employed at the receiver to suppress the noise component of a communication signal received at the receiver.Type: GrantFiled: April 24, 2000Date of Patent: May 29, 2007Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Anders Eriksson, Erik Ekudden
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Patent number: 7221711Abstract: The multilevel data encoding and modulation technique uses a pair of complementary logic sets. In its most basic form, the sets are binary sets each containing a line level for a logical one and a line level for a logical zero for a total of four logic levels. The encoding technique requires a polar change in the line level after every bit. An optional fifth level may be used in order to skew the frequency or to enable automatic gain control circuitry to ensure consistent level discrimination. The encoding technique may be used in a bipolar device, or a bias level may be applied to the signal for unipolar transmission. The encoding technique involves inverting the polarity of alternating bits, filtering out all odd harmonics, transmitting and receiving the waveform, and decoding the demodulated waveform by comparing the absolute value of the half-cycle peak-to-peak voltage gain to a predetermined table.Type: GrantFiled: March 21, 2003Date of Patent: May 22, 2007Inventor: John R. Woodworth
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Patent number: 7215717Abstract: Disclosed is a distortion compensation circuit that reduces the time for convergence of distortion compensation data, without impairing any stability of distortion compensation. The circuit includes an error computation and compensation data updating section that repeats a computation in which errors between an input orthogonal baseband transmission signal and a feedback signal obtained by demodulating part of the output from a power amplifier are computed to obtain error data and values obtained by multiplying this error data by step coefficients are added to distortion compensation data before updating, thereby computing distortion compensation data after updating. Distortion compensation data for compensation of nonlinear distortion is thus updated. Step coefficients are stored in a step coefficient data memory with respect to each of different input signal amplitude values.Type: GrantFiled: December 18, 2002Date of Patent: May 8, 2007Assignee: NEC CorporationInventor: Yoshiaki Doi
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Patent number: 7212582Abstract: In one embodiment, a device includes but is not limited to: a precoder having a precoder input and a precoder output; a spectral shaper, having a spectral-shaper transfer function and being operably coupled internal to said precoder; and a precoder filter, internal to the precoder, the precoder filter having a transfer function which provides substantially the inverse of the spectral-shaper transfer function.Type: GrantFiled: November 20, 2002Date of Patent: May 1, 2007Assignee: Mindspeed Technologies, Inc.Inventor: Xuming Zhang
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Patent number: 7203375Abstract: A quantization error compensation includes a dividing unit to divide an input current image signal into a first high-frequency signal and a low-frequency signal; a changing unit to replace bits of the first high-frequency signal with a predetermined signal to output a second high-frequency signal; an adding unit to add the low-frequency signal and the second high-frequency signal to create a composite signal; a quantization unit to cut n number of bits of the composite signal and to output the cut composite signal and the n number of bit signal; an equalizing unit to output a brightness equalizing value of the cut composite signal; a calculating unit to calculate a compensation value using the n number of the bit signal and a difference between brightness equalizing values with respect to a current and next brightness levels; and a compensation unit to add the compensation and the current brightness equalizing values.Type: GrantFiled: July 9, 2003Date of Patent: April 10, 2007Assignee: Samsung Electronics Co., Ltd.Inventors: Yung-jun Park, Jae-hwan Oh
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Patent number: 7194244Abstract: A wireless communication receiver that is able to lessen the effect of noise that accompanies gain change by programmable gain amplifiers. The receiver includes an AGC controller which controls the timing at which the programmable gain amplifiers make gain change, using a terminal counter and a sequencer. The receiver prevents gain change noise signals during the reception of control signals and other signals that are susceptible to noise. By the timing control feature, the programmable gain amplifiers make gain change while reducing noise impact.Type: GrantFiled: September 25, 2002Date of Patent: March 20, 2007Assignee: Renesas Technology CorporationInventors: Yukinori Akamine, Hisayoshi Kajiwara, Satoshi Tanaka, Takashi Yano, Hirotake Ishii, Akio Yamamoto, Kazuaki Hori, Kazuhiko Hikasa
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Patent number: 7190727Abstract: An impairment compensation sequence for use in a communications system susceptible to one or more potential impairments each periodic in an integer number of symbols includes N phases, wherein N is selected such that each potential impairment, if present, is periodic therein, and a sequence of symbols, the sequence organized to place at least one instance of each symbol from a predetermined set of symbols in each phase to allow detection of the potential impairments in each of the N phases. The potential impairments may include robbed-bit signaling and padding. Using estimates prepared based on such an impairment compensation sequence, individual phase intervals may be grouped according to similarity of apparent aggregate effect of the impairments thereon without identification of individual impairments active in the particular phases. Constellation points may then be assigned based on group characteristics corresponding to phase intervals.Type: GrantFiled: July 28, 2000Date of Patent: March 13, 2007Assignee: Broadcom CorporationInventor: Haixiang Liang
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Patent number: 7190741Abstract: Method and apparatus for estimating signal-to-noise ratio (SNR) ? of a composite input signal e(t) on a phase-modulated (e.g., BPSK) communications link. A first demodulator receives the composite input signal and a stable carrier signal and outputs an in-phase output signal; a second demodulator receives the composite input signal and a phase-shifted version of the carrier signal and outputs a quadrature-phase output signal; and phase error ?E(t) contained within the composite input signal e(t) is calculated from the outputs of the first and second demodulators. A time series of statistically independent phase error measurements ?E(t1), ?E(t2), . . . , ?E(tk) is obtained from the composite input signal subtending a time interval ?t=tk?t1 whose value is small enough such that ?(t) and ?(t) can be taken to be constant in ?t.Type: GrantFiled: October 21, 2002Date of Patent: March 13, 2007Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space AdministrationInventor: Robert M. Manning
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Patent number: 7127011Abstract: A method of and system for detecting whether a peak of a correlation function derived from a received signal is due to a jammer. The peak is within a localized portion of the correlation function which has a total number of peaks. In one embodiment, the total number of peaks is compared to a threshold number of peaks, and the peak is identified as being due to a jammer if the total number of peaks equals or exceeds a threshold number of peaks. In a second embodiment, the peak energy in relation to a noise estimate for the localized portion of the correlation function is compared to a jammer threshold. The peak is identified as being due to a jammer if the peak energy in relation to the noise estimate is less than or equal to the jammer threshold.Type: GrantFiled: August 29, 2002Date of Patent: October 24, 2006Assignee: Qualcomm IncorporatedInventor: Douglas N. Rowitch
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Patent number: 7123659Abstract: A digital reception apparatus includes a receiver that processes a received signal and a distortion corrector that corrects a non-linear distortion of the processed received signal, introduced by the receiver. The receiver may include an amplifier, a quadrature demodulator and/or a quantizer. The distortion corrector includes a distortion estimator that estimates the distortion and outputs a correcting signal based on an inverse distortion characteristic of the receiver, and a distortion compensator that multiplies the received signal and the correcting signal to remove the non-linear distortion from the received signal, to obtain a corrected received signal. The corrected signal is output to a demodulator, which performs demodulation processing on the corrected signal, and thereby obtains a demodulated signal.Type: GrantFiled: March 22, 2001Date of Patent: October 17, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masayuki Orihashi, Katsuaki Abe, Job Cleopa Msuya, Shinichiro Takabayashi
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Patent number: 7088978Abstract: A communication receiver improves its channel estimation performance, its equalization performance, or both, by modeling the non-Gaussian characteristics of a dominant source of interference in a received signal. That is, rather than using Gaussian-based modeling, the receiver generates signal disturbance estimates using a probabilistic model representative of the non-Gaussian interference in a received signal, such as adjacent channel or co-channel signal interference in mobile station operating within a wireless communication network. The receiver may use such non-Gaussian interference modeling responsive to detecting such interference in the received signal and may match its disturbance model to the detected interference. Further, where signal disturbance is predominantly Gaussian in nature, the receiver may switch to a Gaussian disturbance model.Type: GrantFiled: February 7, 2003Date of Patent: August 8, 2006Assignee: Ericsson Inc.Inventors: Dennis Hui, Rajaram Ramesh
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Patent number: 7046811Abstract: For the noise reduction of an audio signal generated by stereo-demultiplexing of a frequency-modulated stereo multiplex signal (SFM(t)) a filtering within the signal path to generate the stereo difference signal (ud(t)) is performed that determines a weight with which the upper sideband (ud,u(t)) and the lower sideband (ud,l(t)) of the amplitude modulated stereo-difference signal are weighted with different weighting factors that are dependent on the frequency.Type: GrantFiled: July 19, 2000Date of Patent: May 16, 2006Assignee: SONY International (Europe) GmbHInventor: Jens Wildhagen
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Patent number: 7023927Abstract: A method for constellation design in a telecommunications network using pulse code modulation to transmit data signals upstream between client and server voice-band modems. The invention selects a constellation for transmission over an analog channel of an equivalence class of data points using pulse code modulation based on the presence or absence of robbed bit signaling and interference from echo levels. The constellation is designed by determining noise in a PCM channel using a cumulative distribution function for echo, determining the extent of said noise for an array of possible constellation points, and selecting constellation points such that the largest negative noise of a first point remains above the largest positive noise level of a neighboring second point. Constellations are created off-line and stored for retrieval during modulation depending on the level of the echo.Type: GrantFiled: April 12, 2002Date of Patent: April 4, 2006Assignee: Texas Instruments IncorporatedInventor: Cory Samuel Modlin
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Patent number: 7020210Abstract: Inter-device adaptable interfacing clock skewing. The invention is operable in either one of both of a transmit mode and a receive mode to perform skewing of a transmitted and/or a received signal. The operational parameters including frequency and phase may be determined during auto detect/auto negotiation, they may be programmed externally, or they may be user selected in various embodiments. A device may include a clock generator, one or more divider, and one or more delay cells internally to the device. If desired, a high frequency clock is generated within the device and then divided down to generate the appropriate clock signal that supports the communication and interaction between multiple devices. Registers and/or pins may be used to select the clock frequency and phase of output clock signals. The present invention supports multiple Ethernet protocols between multiple devices including 10BaseT, 100BaseT, and 1000BaseT.Type: GrantFiled: November 16, 2001Date of Patent: March 28, 2006Assignee: Broadcom CorporationInventors: Andrew J. Castellano, Pieter Vorenkamp, Chun-Ying Chen
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Patent number: 6978015Abstract: A method that sends upstream a collection of data samples measured from a DSL line.Type: GrantFiled: November 10, 2000Date of Patent: December 20, 2005Assignee: Tokyo Electron LimitedInventors: Mark Alan Erickson, Ioannis Kanellakopoulos, John Josef Hench, Sunil C. Shah, James W. Waite, Michail Tsatsanis, Gurcan Aral
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Patent number: H2147Abstract: A method for digital preemphasizer high fidelity reconstruction of an original pulse code modulation (PCM) serial stream binary data signal which has suffered degradation of fidelity, and consequent increase in bit-error-rate, during transmission on a single channel from a transmitter to a receiver. Prior to transmission, amplitude encoded digital pre-emphasis of each bit of the original binary data signal to be transmitted mitigates or remedies the signal degrading frequency dependent losses concomitant with the signal transfer network characteristics of the fixed transmission line. Subsequently, the amplitude encoded signal is transmitted to the receiver connected to the other end of the fixed transmission line. Compared to a conventional transmitter, transmision line, and receiver system, the end result of amplitude encoded pre-emphasis is superior reconstructed fidelity and quality of the PCM waveform, i.e. lower bit-error-rate, at the output of the receiver for the same length of transmission line.Type: GrantFiled: April 23, 2001Date of Patent: March 7, 2006Assignee: The United States of America as represented by the Secretary of the NavyInventor: Jerry H. Ross