By Filtering (e.g., Digital) Patents (Class 375/350)
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Publication number: 20140036736Abstract: The present disclosure relates to compensation for Passive Intermodulation (PIM) distortion in a receiver. In one embodiment, a main receiver receives a radio frequency receive signal and outputs a main receiver output signal. In order to compensate for PIM distortion, a tunable non-linear circuit generates an Intermodulation Products (IMP) signal that includes a number of IMPs as a function of a signal that is indicative of the radio frequency transmit signal. An auxiliary receiver receives the IMP signal and outputs an auxiliary receiver output signal that includes only a subset of the IMPs that fall within a passband of the main receiver. The auxiliary receiver output signal is adaptively filtered to provide a PIM estimate signal, which is then subtracted from the main receiver output signal to provide a compensated output signal.Type: ApplicationFiled: August 2, 2012Publication date: February 6, 2014Applicant: TELEFONAKTIEBOLAGET L M ERICSSON (PUBL)Inventor: Mark Wyville
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Patent number: 8644437Abstract: A method for digital compensation of a nonlinear system comprises identifying a plurality of circuit parameters of a nonlinear system. Each circuit parameter determines a nonlinear response of the nonlinear system. A first circuit parameter is chosen from the plurality of circuit parameters. The first circuit parameter determines a first effect on the nonlinear response. The first effect is at least as large a second effect from a second circuit parameter from the plurality of circuit parameters. At least one stimulus is applied to the nonlinear system. The nonlinear response of the nonlinear system is measured in response to the at least one stimulus. A compensation architecture is synthesized to substantially linearize the nonlinear response. The compensation architecture receives the nonlinear response of the nonlinear system and provides a substantially linear response.Type: GrantFiled: September 8, 2011Date of Patent: February 4, 2014Assignee: Massachusetts Institute of TechnologyInventors: Helen H. Kim, Merlin R. Green, Benjamin A. Miller, Andrew K. Bolstad, Andrew R. Chen, Daniel D. Santiago
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Patent number: 8644428Abstract: A system and method for channel interpolation in a wireless device. In one embodiment a wireless device includes a channel estimator. The channel estimator is configured to generate estimated channel coefficients for a wireless channel over which the wireless device receives a packet. The channel estimator includes an interpolation filter. The interpolation filter is configured to provide interpolated channel coefficients for a plurality of non-pilot sub-carriers. The interpolated channel coefficients are based on pilot sub-carriers of non-preamble symbols.Type: GrantFiled: October 28, 2011Date of Patent: February 4, 2014Assignee: Texas Instruments IncorporatedInventors: Taejoon Kim, Timothy M. Schmidl
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Patent number: 8644416Abstract: A transmitter transmits to a receiver a training sequence having symbols belonging to a single modulation scheme. At least 90% of symbols have low symbol amplitude, and at most 10% of the symbols have high symbol amplitude. A first symbol estimator estimates the symbols using substantially only the sign of the received symbols, and substantially disregarding symbol amplitudes. A timing recovery mechanism estimates the received symbols in order to continuously reduce a frequency drift between the receiver and the transmitter. The first symbol estimator is switched off and a second symbol estimator is switched on according to a certain criterion. The second symbol estimator estimates symbols belonging to the training sequence. Each of the symbols is estimated to either the low symbol amplitude or the high symbol amplitude. An equalizer uses the symbols estimated by the second symbol estimator to converge, achieve signal equalization, and eliminate inter-symbol interference.Type: GrantFiled: September 5, 2013Date of Patent: February 4, 2014Assignee: Valens Semiconductor Ltd.Inventors: Eyran Lida, Gaby Gur Cohen
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Patent number: 8644406Abstract: The present invention relates to a method of transmitting and receiving signals and a corresponding apparatus. One aspect of the present invention relates to a method of extracting PLP from data slices.Type: GrantFiled: May 12, 2009Date of Patent: February 4, 2014Assignee: LG Electronics Inc.Inventors: Woo Suk Ko, Sang Chul Moon
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Publication number: 20140029707Abstract: A receiver circuit includes a first mixer that performs frequency conversion on a first signal of containing a first frequency entered from outside to output the resulting frequency-converted first signal, and a first selector that selects one out of an output signal of the first mixer and a second signal containing a second frequency entered from outside. A filter removes a pre-set frequency band of the signal selected by the first selector, and a second selector that selects between outputting the signal removed of the frequency band to outside and outputting the signal to a subsequent side circuit. A second mixer performs frequency conversion of the signal output from the second selector to output the resulting frequency-converted signal. The second mixer is the subsequent side circuit. The second frequency has a carrier frequency of a radio signal.Type: ApplicationFiled: March 28, 2012Publication date: January 30, 2014Applicant: NEC CORPORATIONInventor: Masaki Kitsunezuka
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Patent number: 8638892Abstract: An input signal that includes narrowband interference is spectrally enhanced by an adaptive circuit that supplies as output signal(s), portion(s) of NBI at one or more frequencies that change adaptively. The output signal(s) are used in one or more tone predictor(s) to generate, based on prior values of the NBI portion, one or more predicted tone signals that are subtracted from a received signal containing the NBI, and the result is used in the normal manner, e.g. decoded. The adaptive circuit and the one or more tone predictor(s), form a feed-forward NBI predictor wherein the received signal is supplied as the input signal of the adaptive circuit. The result of subtraction may be supplied to a slicer that slices the result, yielding a sliced signal which is subtracted from the received signal to generate a signal can be used as the input signal, to implement a feedback NBI predictor.Type: GrantFiled: November 22, 2010Date of Patent: January 28, 2014Assignee: Applied Micro Circuits CorporationInventors: Dariush Dabiri, Maged F. Barsoum
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Patent number: 8638893Abstract: Various embodiments of communication devices and associated methods for reducing I/Q impairments in signals used by the communication devices are described. A transmitter device 206 may perform filtering (or matrix multiplication) on digital I and Q signals to pre-correct them before converting them into analog I and Q signals. The pre-correction may pre-compensate for I/Q impairments which have not been introduced yet, but which will subsequently be introduced during digital to analog conversion, I/Q modulation, or other processing that occurs to produce a transmission signal from the original digital I and Q signals. A receiver device may receive a transmission signal, produce digital I and Q signals from it, and perform filtering on the digital I and Q signals to correct I/Q impairments at a plurality of frequency offsets.Type: GrantFiled: February 24, 2012Date of Patent: January 28, 2014Assignee: National Instruments CorporationInventors: Stephen L. Dark, Daniel J. Baker
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Patent number: 8638174Abstract: The invention relates to a digital signal generator for providing one or more phases of a local oscillator signal for use in digital to analogue converters and harmonic rejection mixers. Embodiments disclosed include a local oscillator signal generator (200) for a mixer of a radiofrequency receiver, the signal generator (200) comprising a bit sequence generator (201) having a plurality of parallel output lines (203), a digital signal generator (202) having a serial output line (204) and a plurality of input lines connected to respective output lines (203) of the bit sequence generator (201) and a clock signal input line (205), wherein the digital signal generator (202) is configured to provide an output bit sequence on the serial output line (204) at a rate given by a clock signal provided on the clock signal input line (205) and a sequence given by a sequence of bits from the bit sequence generator (201) on the plurality of input lines (203).Type: GrantFiled: May 26, 2011Date of Patent: January 28, 2014Assignee: Integrated Device Technology inc.Inventors: Nenad Pavlovic, Johannes Hubertus Antonius Brekelmans, Jan van Sinderen
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Patent number: 8638891Abstract: A communication system includes a physical communication channel. A signal is transmitted across the communication channel from a transmit end of the channel to a receive end of the channel. A plurality of processing branches process the signal at the receive end of the communication channel. This reduces complexity of the receive channel, without reducing a bandwidth of the given communication channel, and without comprising performance.Type: GrantFiled: July 3, 2012Date of Patent: January 28, 2014Assignee: Seagate Technology LLCInventor: Mehmet Fatih Erden
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Patent number: 8638888Abstract: One embodiment of the present invention relates to an analog correlation unit comprising a plurality of parallel correlation components configured to operating according to an advanced switched-capacitor low pass filter principle that increases coding gain of the unit. Each correlation component comprises a sampling stage and a correlation stage. The sampling stage may comprise a switched capacitor configured to sample a received baseband signal to determine a value (e.g., polarity) of the baseband signal. The sampled baseband signal is provided to the correlation stages, which may respectively comprise a plurality of switched integrators configured to selectively receive and integrate the sampled baseband signal over time depending upon values (e.g., polarity) of the correlation code to generate voltage potential values. The analog correlation result is evaluated by a comparison of an adjustable threshold voltage with the difference between the output voltage potential values.Type: GrantFiled: July 21, 2011Date of Patent: January 28, 2014Assignee: Infineon Technologies AGInventors: Christian Hambeck, Stefan Mahlknecht, Thomas Herndl, Franz Darrer, Jakob Jongsma
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Patent number: 8638883Abstract: A method includes receiving a signal using a direct conversion receiver, while the receiver is set at a gain that is selected from a range of possible gain values. Multiple DC offset correction values are provided for use by a DC offset cancellation loop, each DC offset correction value being associated with a respective sub-range of the range of the possible gain values. A DC offset correction value is selected from among the multiple DC offset correction values based on the gain to which the receiver is set. A DC offset in the signal is canceled by setting the DC offset cancellation loop to the selected DC offset correction value.Type: GrantFiled: February 1, 2011Date of Patent: January 28, 2014Assignee: Marvell World Trade Ltd.Inventors: Rony Ashkenazi, Alexander Zaslavsky, Gregory Uehara, Brian Brunn
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Patent number: 8634507Abstract: A receiver comprises an adaptive filter having an input for a digitized input signal, means for storing a pre-designed filter characteristic, means for analyzing a digital. representation of the input signal to determine a desired position of the filter characteristic to match the system requirements, and means for adapting the stored pre-designed filter characteristic in the frequency domain and/or the time domain to match the system requirements and for transforming the adapted filter characteristic to the time domain to update coefficients for the adaptive filter and for loading updated coefficients into adaptive filter. The updating of the coefficients may be done periodically. The adaptation may be one or more of adjusting bandwidth, frequency shift and, in the case of a bandpass characteristic, superimposing characteristics.Type: GrantFiled: December 22, 2011Date of Patent: January 21, 2014Assignee: ST-Ericsson SAInventor: Robert Fifield
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Patent number: 8634454Abstract: A receiver circuit includes: an equalization circuit that equalizes a first signal to obtain a second signal, and adjusts a characteristic of an equalization in accordance with an error between the second signal and a third signal; and a first offset adjustment circuit that adjusts an offset of the first signal in accordance with an error signal indicating the error.Type: GrantFiled: June 29, 2010Date of Patent: January 21, 2014Assignee: Fujitsu LimtedInventors: Masaya Kibune, Hirotaka Tamura
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Publication number: 20140016691Abstract: Systems and methods are disclosed for interference suppression in a mobile device (MS). In certain embodiments, the MS uses handover measurements to detect and measure the interference powers of neighbor cells and sorts them with respect to their power levels. An RSRP ratio of serving cell RSRP to neighbor cell RSRP may be used to determine the interference power levels of the neighbor cells. Alternately, RSRQ may be used to determine the interference power levels of the neighbor cells. The MS may estimate the interference of each cell with an interference power level above a certain threshold and then subtract each interference estimate from the total received signal until all the selected interferers are suppressed. In certain embodiments, the interference suppressed signal may then be equalized and/or decoded. Equalization may occur during suppression of interference from individual neighbor cells or after all neighbor cell interference estimates have been subtracted.Type: ApplicationFiled: July 15, 2013Publication date: January 16, 2014Inventor: Aykut Bultan
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Patent number: 8630337Abstract: A method for demodulating a modulated signal, by: receiving a signal modulated in n-PSK or n-APSK comprising a succession of symbols organized in frames, each frame comprising a header followed by blocks of data symbols separated by blocks of pilot symbols, determining the phase of the headers and pilot blocks to predict the evolution of the signal phase, correcting the phase of the data symbols according to the evolution of the signal phase, and equalizing the data symbols corrected in phase using equalization coefficients evaluated thanks to estimated or known symbols of the signal, and pre-equalizing the header, pilot and data symbols, which is performed before determining the phase of the headers and pilot blocks, and using the estimated equalization coefficients to equalize the data symbols.Type: GrantFiled: May 25, 2010Date of Patent: January 14, 2014Assignee: STMicroelectronics (Grenoble 2) SASInventor: Jacques Meyer
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Patent number: 8630381Abstract: Disclosed is a dual band receiver which includes an analog-to-digital converter configured to convert a dual band analog RF signal into a dual baseband digital signal; and a first signal extractor configured to generate a first path signal and a second path signal from the dual baseband signal and to extract a first baseband signal using a relative sample delay difference between the first and second path signals, wherein the dual baseband signal includes the first baseband signal and a second baseband signal, the first path signal is a signal obtained by sample delay of the dual baseband signal and then down sampling of a resultant signal, and the second path signal is a signal obtained by down sampling of the dual baseband signal without sample delay.Type: GrantFiled: September 23, 2011Date of Patent: January 14, 2014Assignee: Electronics and Telecommunications Research InstituteInventors: Seok Seo, Hyung Jung Kim, Jin Up Kim
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Patent number: 8630375Abstract: The present disclosure provides an apparatus and method for advantageously simplifying joint detection processing in one or more demodulation stages of a multi-stage receiver by configuring at least one stage to use a constrained multi-user search, such as a constrained tree search. For example, a multi-stage receiver includes at least two stages configured to successively process a received composite signal that includes signal contributions from two or more “users”, which, for example, means that the received signal includes two or more symbol streams. In a non-limiting example, particular embodiments of the present invention combines constrained tree searching with Serial Localized Indecision (SLIC) processing in a multi-stage receiver, where each stage includes a joint processing unit. At least one of those stages is configured to use a constrained multi-user search, rather than a full search, for jointly detecting symbols in the stage input signal.Type: GrantFiled: July 10, 2012Date of Patent: January 14, 2014Assignee: Telefonaktiebolaget LM Ericsson (Publ)Inventors: Ali Khayrallah, Stephen Grant
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Patent number: 8630377Abstract: A method of detecting interference in a received sample vector using hidden Markov modelling by first estimating noise variance, where estimating noise variance comprises the steps of receiving a sample vector of noise and interference, sorting the sample vector in the frequency domain by order of increasing magnitude to produce an ordered vector, finding a sub-vector of the ordered vector that minimizes the distance from a noise measure, and estimating the noise variance.Type: GrantFiled: December 21, 2007Date of Patent: January 14, 2014Assignee: Industrial Research LimitedInventor: Alan James Coulson
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Patent number: 8630380Abstract: To improve the degree of removal of unwanted component signals with a small area while eliminating the need for a high-frequency signal source. IF band simulated image signals IM-I, IM-Q output from an IF band simulated image signal generating unit (12) are input to a quadrature mixer (14) through a path switch (13). The signals IM-I and IM-Q which are fed through and output from the quadrature mixer (14) are output from a complex filter (16), and the amplitudes of the signals IM-I and IM-Q are detected by an amplitude detecting unit (17). Based on the detected amplitudes, an element value control unit (18) controls element values of constituent elements of the complex filter (16) so as to decrease the amplitudes.Type: GrantFiled: December 25, 2009Date of Patent: January 14, 2014Assignee: NEC CorporationInventor: Masaki Kitsunezuka
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Patent number: 8625726Abstract: A radio frequency to digital receiver has a modulator sampling a signal at a first rate. The receiver has at least one processing unit. The processing unit has a plurality of digital bandpass filters separating the signal and recombining the signal at a rate less than the first rate. The processing unit has a digital down converter adjusting frequency offset or centering the signal at the rate less than the first rate. The receiver has at least one rate control buffer coupled to adjacent processing units when two or more processing units are within the receiver.Type: GrantFiled: September 15, 2011Date of Patent: January 7, 2014Assignee: The Boeing CompanyInventors: Yen-Cheng Kuan, Zhiwei Xu
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Patent number: 8625217Abstract: Techniques are disclosed for performing branch metric computations/noise predictive calibration/adaptation for over-sampled Y samples. In one or more embodiments, the techniques employ a data processing apparatus (circuit) that includes a parallel to serial convertor configured to receive a first stream of sample data (e.g., Y samples) and a second stream of sample data (e.g., Z samples). The parallel to serial convertor is operable to combine the first stream of sample data and the second stream of sample data into a combined stream of sample data (e.g., combined Y and Z samples). The data processing apparatus (circuit) further includes a filter (e.g., a noise predictive finite impulse response (NPFIR) filter, a noise whitening filter, such as a noise predictive calibration/adaptation module (NPCAL) filter, and so forth) that is configured to receive the combined stream of sample data and whiten noise in the combined stream of sample data.Type: GrantFiled: September 27, 2012Date of Patent: January 7, 2014Assignee: LSI CorporationInventors: Shaohua Yang, Xuebin Wu
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Patent number: 8619928Abstract: A multi-stage interference suppression receiver includes a short equalizer section configured to operate on a first portion of a received signal received over a channel to produce a first equalized signal and a first estimate of the channel, a channel estimator section configured to operate on the first equalized signal to produce a second equalized signal, the channel estimator section comprising a linear estimator and a non-linear estimator, a long equalizer section configured to operate on a second portion of the received signal to produce a first estimate of symbols in the received signal and a second estimate of the channel and an interference canceller section configured to operate on the first estimate of symbols in the received signal to generate a second estimate of symbols in the received signal based on, at least in part, the second estimate of the channel.Type: GrantFiled: September 3, 2009Date of Patent: December 31, 2013Assignee: Qualcomm IncorporatedInventors: Farrokh Abrishamkar, Divaydeep Sikri, Raghu N. Challa, Bahadir Canpolat
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Patent number: 8619921Abstract: A channel estimation device comprises: a channel variation detection unit that determines whether variation width of a received signal level is not less than preset threshold width and whether variation period of received signal is not greater than preset threshold period; and a channel estimation unit that, if the channel variation detection unit determines that the variation width of the received signal level is not less than preset threshold width and that variation period is not greater than preset threshold period, refers to hysteresis of received signal level to determine whether lowering of received signal level is temporal, and, if it is determined that lowering of received signal level is temporal, allowing received signal to pass through, without removing received signal as noise, even when received signal level is not greater than signal level to be removed as noise.Type: GrantFiled: June 21, 2010Date of Patent: December 31, 2013Assignee: NEC CorporationInventor: Masato Shiokawa
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Patent number: 8619929Abstract: A positioning signal reception device receives a positioning signal transmitted from a position information satellite, and includes: a signal reception portion that obtains a reception signal by receiving the positioning signal; an A/D conversion portion that generates a digital signal by converting the reception signal into a digital form; a filter portion that subjects the digital signal to frequency separation, a characteristic of the filter portion being changeable; a filter characteristic change portion that changes the characteristic of the filter portion according to an operating state of the positioning signal reception device and an external environmental condition of the positioning signal reception device; and a code synchronization establishment portion that establishes synchronization of spreading codes contained in the reception signal.Type: GrantFiled: October 6, 2009Date of Patent: December 31, 2013Assignee: Seiko Epson CorporationInventor: Makoto Murakami
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Publication number: 20130343443Abstract: A system for classifying impulsive noise on a communications signal comprises an impulse signal generator, an integrator, a first comparator, and an impulse peak detector. The impulse signal generator receives a communications signal that includes impulsive noise and is configured to provide an impulse signal that includes just the impulsive noise. The integrator receives the impulse signal and integrates the impulse signal to determine the power of the impulse signal. The first comparator receives the impulse signal and is configured to compare the impulse signal to a first reference signal and indicate the time during which the value of the impulse signal is greater than the value of the first reference signal. The impulse peak detector receives the impulse signal and is configured to process the impulse signal, compare the processed signal to a second reference signal, and detect the peak value of the impulse signal.Type: ApplicationFiled: June 26, 2013Publication date: December 26, 2013Inventors: Alain Charles Briancon, John Berns Lancaster, Curtis Scott Crawford, Robert Leon Lutes, Eric Alexander Shumaker, Marc Anthony Epard
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Publication number: 20130343495Abstract: An error correction data processing apparatus includes a noise predictive calibration circuit operable to calibrate a first set of filter coefficients based on a first data set and a second set of filter coefficients based on a second data set, and includes a first noise predictive detector operable to receive the first set of filter coefficients. The apparatus further includes a decoder operable to perform a first global iteration with the first noise predictive detector and determine a violation check count value, and a second noise predictive detector operable to receive the second set of filter coefficients if the violation check count value is less than a predetermined value or receive the first set of filter coefficients if the violation check count value is greater than the predetermined value.Type: ApplicationFiled: June 26, 2012Publication date: December 26, 2013Applicant: LSI CORPORATIONInventors: Yang Han, Shaohua Yang, Fan Zhang, Zongwang Li
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Patent number: 8615062Abstract: Described embodiments provide method of adapting pulse response taps of a receiver. An analog-to-digital converter (ADC) generates an ADC value for each bit sample of a received signal. An error signature analysis (ESA) module defines a window of bit samples and, for the window, estimates a bit value corresponding to each sample based on the ADC value. The ESA module generates (i) a reconstructed ADC value corresponding to an estimated cursor bit based on a number of pre-cursor estimated bits, the estimated cursor bit, and a number of post-cursor estimated bits, and (ii) an error signature value based on the reconstructed ADC value and the ADC value. Based on the error signature value and a minimum pulse response value, it is determined whether the cursor bit corresponds to residual inter-symbol interference (ISI), and, if so, the error signature value is accumulated and tap values for each pulse response tap are adapted.Type: GrantFiled: February 7, 2012Date of Patent: December 24, 2013Assignee: LSI CorporationInventor: Erik V. Chmelar
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Patent number: 8615210Abstract: Methods and apparatus for power measurement in a communication system. In an aspect, a method is provided for power measurement. The method includes selecting between a signal decoding mode and a power measurement mode, decoding an input signal if the signal decoding mode is selected, and calculating a power measurement associated with the input signal if the power measurement mode is selected. In another aspect, an apparatus is provided for power measurement. The apparatus includes means for selecting between an active mode and a power measurement mode, means for decoding an input signal if the active mode is selected, and means for calculating a power measurement associated with the input signal if the power measurement mode is selected.Type: GrantFiled: January 18, 2007Date of Patent: December 24, 2013Assignee: QUALCOMM IncorporatedInventors: Ashok Mantravadi, Phani Bhushan Avadhanam, Vinay Murthy
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Patent number: 8615061Abstract: A method and apparatus in which a Tap-Weight Computer (TWC) calculates a Tap-Weight Vector (TWV) are provided. The TWV is coupled to a register in an adaptive filter module. Each adaptive filter module includes several adaptive filters that each include a tapped delay line. The input to the tapped delay line is one of a plurality of potential interfering signals. The TWV controls the weighting of the outputs from the taps off the delay line. The weighted outputs from each tapped delay line are subtracted from a received signal which potentially includes interference from the potential interfering signals. The TWC is multiplexed to each of the plurality of adaptive filters so that each adaptive filter is loaded with a TWV calculated by the TWC to reduce the amount of interference contributed by a particular potential interfering signal coupled to an input to that particular adaptive filter.Type: GrantFiled: July 28, 2011Date of Patent: December 24, 2013Assignee: Entropic Communications, Inc.Inventors: Branislav Petrovic, Michail Tsatsanis
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Publication number: 20130336433Abstract: Disclosed are a receiving apparatus, a receiving method, and a program capable of reliably obtaining predetermined information. In a case where a broadband signal where the same control information is arranged in different frequency bands is received and processed, a frequency where the control information is stably received is detected, and the control information is obtained again using the detected frequency. This frequency detection is performed by detecting a frequency capable of avoiding a no-signal band in a signal array of the broadband signal determined based on the obtained control information and the like. This technology can be applied to a receiving apparatus that receives a signal conforming to a DVB-C2 standard.Type: ApplicationFiled: March 29, 2012Publication date: December 19, 2013Applicant: SONY CORPORATIONInventors: Hiroo Takahashi, Yuken Goto, Takuya Okamoto
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Patent number: 8611409Abstract: A method is provided for performing channel equalization on a wireless signal. The method includes: (i) formulating an equalizer associated with sub-carriers of the wireless signal, wherein the equalizer is a function of a quantity relating to signal quality (305); (ii) determining an adjoint of the equalizer over a selected number of the subcarriers (310); (iii) interpolating the adjoint determined in (ii) to obtain an adjoint of the equalizer over remaining ones of the subcarriers of the wireless signal (315); and (iv) generating an equalized signal for each of the subcarriers using the adjoint of the equalizer over the selected number of subcarriers and the interpolated adjoint over the remaining ones of the subcarriers (320).Type: GrantFiled: December 16, 2008Date of Patent: December 17, 2013Assignee: Motorola Mobility LLCInventors: Anahid Robert, David G. Bateman, Philippe Bernardin, Stephanie Rouquette-Leveil
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Patent number: 8611410Abstract: A system, method and memory medium for performing blind equalization. A block {un} of the baseband samples is received. A function J of a vector f is minimized to determine a minimizer fMIN. The function J depends on vector f according to J(f)=?(|yn|2??)2. The summation ? corresponds to a sequence {yn} of equalized samples. The sequence {yn} of equalized samples is related to the block {un} according to a convolution relation {yn}={un}*f. Parameter ? is a current modulus value. The current modulus value ? is updated to equal a ratio of a fourth moment of the sequence {yn} to a second moment of the sequence {yn}. The minimization and parameter update operations are repeated for a series of received blocks of baseband samples. The minimizer fMIN from a last of the repetitions is used to determine final equalized samples.Type: GrantFiled: December 23, 2010Date of Patent: December 17, 2013Assignee: National Instruments CorporationInventors: Pratik Prabhanjan Brahma, Baijayanta Ray
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Patent number: 8611937Abstract: A level detection part 221 detects the field intensity of airwaves broadcast by a desired station, and an AM component extraction part 222 and a level detection part 223 cooperate with one another in detecting the multipath noise level. When the field intensity of the airwaves broadcast by the desired station is high and also the multipath noise level is comparatively low, a filter setting part 229 determines filtering processing to be performed by an adaptive filter part 133 as being FIR type filtering processing. And the filter setting part 229 performs settings for FIR type filtering processing on the adaptive filter part 133. As a result, it is possible to enhance the reproduction quality of the broadcast content sent by the desired station that has been tuned.Type: GrantFiled: March 5, 2010Date of Patent: December 17, 2013Assignee: Pioneer CorporationInventor: Hideyuki Kanno
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Patent number: 8611485Abstract: A device for controlling frequency synchronization includes a processor for controlling a frequency-controlled clock signal on the basis of received timing messages so as to achieve frequency-locking between the frequency-controlled clock signal and a reference clock signal. For the purpose of finding such timing messages which have experienced similar transfer delays and thus are suitable for the frequency control, the processor is configured to control a phase-controlled clock signal on the basis of the timing messages so as to achieve phase-locking between the phase-controlled clock signal and the reference clock signal, and to select the timing messages to be used for the frequency control on the basis of phase-error indicators related to the phase control. Thus, the phase-controlled clock signal is an auxiliary clock signal that is utilized for performing the frequency control.Type: GrantFiled: May 22, 2012Date of Patent: December 17, 2013Assignee: Tellabs OyInventors: Kenneth Hann, Mikko Laulainen
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Patent number: 8611476Abstract: A method and apparatus for estimating a frequency response of a channel. The method includes adjusting phase components of estimates of the frequency response to provide phase-adjusted estimates; performing a smoothing operation on the phase-adjusted estimates to provide smoothed phase-adjusted estimates; and generating an output of a reverse phase adjustment, wherein the reverse phase adjustment is performed on the smoothed phase-adjusted estimates.Type: GrantFiled: December 5, 2012Date of Patent: December 17, 2013Assignee: Marvell International Ltd.Inventors: Rohit U. Nabar, Kedar Shirali
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Publication number: 20130329835Abstract: A signal receiver includes an antenna interface for receiving signals from an antenna, analog signal processing circuitry coupled to the antenna interface for processing the received signals to produce filtered signals, sampling circuitry to sample the filtered signals so as to produce digitized received signals, a digital compensator to receive the digitized received signals and compensate for non-uniform group delay and amplitude distortion introduced by the analog signal processing circuitry to produce compensated digitized received signals, and a digital processor to process the compensated digitized received signals so as to produce a result.Type: ApplicationFiled: May 10, 2013Publication date: December 12, 2013Applicant: Deere & CompanyInventors: Richard G. Keegan, Jerry E. Knight
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Publication number: 20130329841Abstract: A signal receiver includes an antenna interface for receiving signals from an antenna, analog signal processing circuitry coupled to the antenna interface for processing the received signals to produce filtered signals, sampling circuitry to sample the filtered signals so as to produce digitized received signals, a digital compensator to receive the digitized received signals and compensate for non-uniform group delay introduced by the analog signal processing circuitry to produce compensated digitized received signals, and a digital processor to process the compensated digitized received signals so as to produce a result.Type: ApplicationFiled: May 10, 2013Publication date: December 12, 2013Applicant: Deere & CompanyInventors: Richard G. Keegan, Jerry E. Knight
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Patent number: 8606193Abstract: An RF transceiver integrated circuit has a novel segmented, low parasitic capacitance, internal loopback conductor usable for conducting IP2 self testing and/or calibration. In a first novel aspect, the transmit mixer of the transceiver is a current mode output mixer. The receive mixer is a passive mixer that has a low input impedance. In the loopback mode, the transmit mixer drives a two tone current signal to the passive mixer via the loopback conductor. In a second novel aspect, only one quadrature branch of the transmit mixer is used to generate both tones required for carrying out an IP2 test. In a third novel aspect, a first calibration test is performed using one quadrature branch of the transmit mixer at the same time that a second calibration test is performed using the other quadrature branch, thereby reducing loopback test time and power consumption.Type: GrantFiled: November 13, 2008Date of Patent: December 10, 2013Assignee: QUALCOMM IncorporatedInventors: Jin-Su Ko, Michael Kohlmann, Bahman Ahrari
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Patent number: 8605840Abstract: A method of canceling impulsive interference from a communications signal is provided. The method includes identifying an impulse interference contained in the communications signal, generating a model of impulse interference, matching the model in at least one of amplitude, phase and envelope time delay to the identified impulse interference, and cancelling the identified impulse interference by subtracting the matched model from the identified impulse interference.Type: GrantFiled: June 2, 2011Date of Patent: December 10, 2013Assignee: Lockheed Martin CorporationInventors: Richard Wasiewicz, Thomas M. Parks
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Patent number: 8605844Abstract: A signal receiver is configured for receiving signals from multiple antennas, wherein the signal from one of the antennas is phase compensated relative to the signal from another of the antennas. The receiver comprises (i) an equalizer configured to equalize signals received from the antennas in accordance with a determined equalization vector and (ii) a processor for determining the equalization vector. The processor is configured to determine the equalization vector in dependence on (i) a first channel estimate for a first channel from one of the antennas to the receiver and (ii) a phase-adjusted version of a second channel estimate for a second channel from another of the antennas to the receiver.Type: GrantFiled: August 3, 2009Date of Patent: December 10, 2013Assignee: Cambridge Silicon Radio LimitedInventors: Andrew Papageorgiou, Jason Woodard
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Publication number: 20130322586Abstract: Methods and apparatus for resuming radio channel measurements and estimations after an interruption in reception. In one exemplary embodiment of the present disclosure, an adaptive solution is provided for channel estimation based at least in part on the reception interruption duration. In one variant, an LTE UE determines a windowing length and/or “shape” for a time domain channel estimation algorithm based on at least the interruption duration. In an alternate variant, an LTE UE determines the interpolation coefficients for a filter based on the interruption duration.Type: ApplicationFiled: May 3, 2013Publication date: December 5, 2013Inventors: Tarik Tabet, Navid Damji, Kee-Bong Song, Syed Aon Mujtaba, Johnson Sebeni, Zhu Ji
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Patent number: 8599975Abstract: A system including a converter, a first filter, a first device, a second filter, and a second device. The converter samples an input signal at multiple sampling times to generate samples. The first filter includes a first taps, which receive first tap weight coefficients. The first filter filters the samples to generate a first output signal based on the first tap weight coefficients. The first device, based on the samples of the input signal, updates the first tap weight coefficients. The second filter includes second taps, which receive second tap weight coefficients. The second filter filters the first output signal to generate a second output signal based on the second tap weight coefficients. The second device, based on the first output signal, updates the second tap weight coefficients. The input signal is sampled based on the second output signal of the second filter.Type: GrantFiled: October 1, 2012Date of Patent: December 3, 2013Assignee: Marvell International Ltd.Inventor: Pantas Sutardja
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Patent number: 8599981Abstract: Provided is a decoding device which suppresses generation of an abnormal sound caused by a layer switch.Type: GrantFiled: February 29, 2008Date of Patent: December 3, 2013Assignee: Panasonic CorporationInventor: Masahiro Oshikiri
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Patent number: 8599909Abstract: This disclosure describes systems and methods for determining a voltage margin (or margin) of a serializer/deserializer (SerDes) receiver in mission mode using a SerDes receiver. This is done by time-division multiplexing a margin determination and a tap weight adaptation onto the same hardware (or software, or combination of hardware and software). In other words, some parts of a SerDes receiver (e.g., an error slicer and an adaptation module) can be used for two different tasks at different times without degrading the effectiveness or bandwidth of the receiver. Hence, the disclosed systems and methods allow a SerDes receiver to determine the SerDes margin in mission mode and without any additional hardware or circuitry on the receiver chip.Type: GrantFiled: August 4, 2010Date of Patent: December 3, 2013Assignee: Oracle International CorporationInventors: Drew G. Doblar, Dawei Huang, Deqiang Song
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Publication number: 20130315357Abstract: Aspects of a method and system for interference cancellation substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims. In this regard, a receiver may be operable to receive a differential signal via a differential channel, and to sense a common mode signal on the differential channel. A frequency range in which interference is present in the common mode signal may be determined. The differential signal and the common mode signal may be filtered to attenuate frequencies outside the determined frequency range. A phase and/or amplitude of the filtered common mode signal may be adjusted based on the filtered differential signal and the adjusted and filtered common mode signal may be subtracted from the received differential signal. The common mode signal may be sensed via a pair of resistors coupled to the differential channel.Type: ApplicationFiled: August 1, 2013Publication date: November 28, 2013Applicant: Broadcom CorporationInventors: Mehdi Tavassoli Kilani, Scott Powell, Kadir Dinc, Kishore Kota, John Creigh, Hooman Parizi
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Patent number: 8594261Abstract: A receiving system and a method for receiving and processing a broadcast signal including mobile service data are disclosed. The receiving system includes a tuner, a demodulator, a block decoder and an RS frame decoder. The tuner receives a broadcast signal including first mobile service data and second mobile service data. The demodulator demodulates the broadcast signal. The block decoder performs turbo-decoding on the first and second mobile service data included in the demodulated broadcast signal. The RS frame decoder builds a primary RS frame by collecting the turbo-decoded first mobile service data and performs error correction decoding on the primary RS frame. The RS frame decoder also builds a secondary RS frame by collecting the second mobile service data and performs error correction decoding on the secondary RS frame.Type: GrantFiled: April 19, 2010Date of Patent: November 26, 2013Assignee: LG Electronics Inc.Inventors: Jin Woo Kim, Byoung Gill Kim, Won Gyu Song, Chul Kyu Mun, Hyoung Gon Lee, In Hwan Choi
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Patent number: 8594258Abstract: Processing a signal comprising signal distortions with filters. The filters comprise a first filter configured to a first time scale to compensate for signal distortions within respective symbols of the signal and a second filter configured to a second time scale to compensate for signal distortions among symbols of the signal. A probability estimate is produced based on an output of at least one of the first and second filters. At least one of the first and second time scales is adjusted according to the probability estimate.Type: GrantFiled: November 9, 2012Date of Patent: November 26, 2013Assignee: Quellan, Inc.Inventors: Andrew Joo Kim, Vincent Mark Hietala, Sanjay Bajekal
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Patent number: 8594259Abstract: A receiving circuit, use, and method for receiving an encoded and modulated radio signal is provided. The circuit comprise a demodulator and a digital filter connected downstream of the demodulator for moving averaging. The filter has at least two FIFO registers and subtractors. Whereby for subtracting an output value of the FIFO register from an input value of the FIFO register a subtractor is connected to each FIFO register. Wherein the filter has a weighting unit, which is connected downstream of each FIFO register, and wherein the filter has an integrator, which is connected downstream of the subtractors for integration.Type: GrantFiled: February 19, 2010Date of Patent: November 26, 2013Assignee: Atmel CorporationInventor: Ulrich Grosskinsky
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Patent number: 8594260Abstract: One embodiment includes a method of receiving a transmitted signal. The method comprises receiving a signal transmitted over a channel. The signal comprises a known signal and an information signal. The method further includes determining at least one indicator of channel characteristics based at least in part on the portion of the known signal. The method further includes generating a first value indicative of the information signal based at least in part on the at least one indicator of the channel characteristics. The first value comprises an error signal. The method further comprises removing the error signal from the first estimate of the signal based at least in part on the portion of the known signal. Other embodiments include systems for performing the method and methods of making such systems.Type: GrantFiled: August 13, 2010Date of Patent: November 26, 2013Assignee: QUALCOMM IncorporatedInventors: Durga Prasad Malladi, Byoung-Hoon Kim, Yongbin Wei