Training Period Or Initial Set Up Patents (Class 375/231)
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Patent number: 9054765Abstract: Systems and methods are provided for suppressing interference from a received data signal. A characteristic of a channel is estimated, the channel being configured for transmission of data between a transmitting device and a receiving device having two or more receive antennas. A spatial correlation of interference is determined for the two or more receive antennas based on the channel characteristic. The received data signal is filtered based on the spatial correlation.Type: GrantFiled: October 19, 2012Date of Patent: June 9, 2015Assignee: MARVELL WORLD TRADE LTD.Inventors: Raphael Cendrillon, Yakun Sun, Hongyuan Zhang, Atul Salhotra, Hui-Ling Lou
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Publication number: 20150131708Abstract: One embodiment provides a network controller. The network controller includes a modulation module. The modulation module includes a high rate (HR) bit sequence generator configured to generate a first high rate bit sequence, encoder circuitry configured to encode a first low rate bit stream, the first low rate bit stream comprising backchannel information, and modulation circuitry configured to modulate the encoded first low rate bit stream onto the first high rate bit sequence. The network controller further includes transmit circuitry configured to transmit the modulated first HR bit sequence to a link partner during a link initialization period.Type: ApplicationFiled: November 8, 2013Publication date: May 14, 2015Inventors: Frank N. Cornett, Brent R. Rothermel
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Patent number: 9031123Abstract: A receiver performs interference mitigation under blind or semi-blind conditions using diversity present in the signal of interest or in the interferer. A first path interference mitigation procedure extracts training information from received signals, performs interference mitigation on the training information and estimates the channel. The second path interference mitigation procedure uses data extracted from the received signal and the channel estimate to perform interference mitigation. Each interference mitigation process can take the form of a lossy compression followed by decompression.Type: GrantFiled: March 15, 2013Date of Patent: May 12, 2015Assignee: Acorn Technologies, Inc.Inventor: Fernando Lopez de Victoria
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Patent number: 9031124Abstract: A method of generating a hypothesis and estimating a CFO includes receiving a signal including a set of radio frames, dividing each received radio frame of the set into a set of received sub-sequences, dividing, each of reference radio frames from a reference signal stored in the receiver into a set of reference sub-sequences, correlating the set of received sub-sequences with the set of reference sub-sequences to obtain a set of correlation values, generating, a first value set and a second value set of hypothesis based on the correlation values, generating a first and a second hypothesis based on the first value and the second value set, and averaging the first and the second hypothesis to obtain an averaged hypothesis, performing a DFT on the averaged hypothesis to obtain a DFT sequence, determining a peak position of the DFT sequence, and estimating the CFO based on the peak position.Type: GrantFiled: February 21, 2014Date of Patent: May 12, 2015Inventors: Shrinivas Bhat, Niranjan Mylarappa Gowda
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Patent number: 9020023Abstract: The present technique relates to a reception device and a reception method which can improve equalization performance. An equalization processing unit has a time domain equalization unit which equalizes a received signal in a time domain and a frequency domain equalization unit which is provided in parallel to the time domain equalization unit and which equalizes the received signal in a frequency domain, and performs control of switching between the time domain equalization unit and the frequency domain equalization unit. The present technique can be applied to, for example, equalize a signal of data transmitted by way of single carrier transmission or data transmitted by way of multicarrier transmission.Type: GrantFiled: May 15, 2012Date of Patent: April 28, 2015Assignee: Sony CorporationInventors: Katsumi Takaoka, Naoki Yoshimochi, Hidetoshi Kawauchi, Ryo Hasegawa, Hirofumi Maruyama
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Patent number: 9020021Abstract: An apparatus for encoding data signals includes a transmitter configured to encode and transmit a data signal over a communication channel, the transmitter including a precoder; a signal shaper configured to adjust the data signal by applying an equalization setting to the data signal, the equalization setting including an amplitude and offset and transmit the adjusted data signal to the precoder; and a processing unit. The processing unit is configured to perform: receiving channel coefficients associated with the communication channel; for each of a plurality of amplitude settings and a plurality of offset settings, calculating whether a modulo amplitude level would occur at a receiver using a modulo operation; selecting the equalization setting from the plurality of amplitude settings and the plurality of offset settings based on the calculation; and transmitting a control signal specifying the equalization setting to the signal shaper.Type: GrantFiled: July 29, 2013Date of Patent: April 28, 2015Assignee: International Business Machines CorporationInventors: Marcel A. Kossel, Daihyun Lim, Pradeep Thiagarajan
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Publication number: 20150110164Abstract: For example in case of an OFDM multicarrier transmission system the transmission characteristics of subcarriers of a multicarrier transmission system using a plurality of antenna elements (3, 3?) can be adjusted. Particularly the power and the phase of the subcarriers can be adapted. To this object the subcarrier frequency channel (2, 2?) characteristics of the multicarrier transmission are detected (11, 11?) at the side of the transmitter (3). The power of each subcarrier is then distributed by a weighting unit (14, 14?). The subcarriers can be further pre-equalized (1, 1?) by dividing the subcarrier signal respectively by the sum of the squared magnitude of the frequency channel characteristics of all subcarrier signals or a frequency characteristic of the selected antenna element (3, 3?).Type: ApplicationFiled: December 30, 2014Publication date: April 23, 2015Applicant: Sony Deutschland GmbHInventors: Ralf BĂ–HNKE, Seiichi IZUMI
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Patent number: 9014318Abstract: Embodiments of the invention comprise a continuous-time equalizer for reducing ISI in data received from a communication channel, and methods and circuitry for tuning or calibrating that equalizer. Selected coefficients for a transfer function of the equalizer circuit are fixed, while other coefficients are tuned by an adaptive algorithm. The adaptive algorithm minimizes errors associated with the tunable coefficients based on one or more training signals sent by the transmitter and received by the equalizer circuit at the receiver. The training signals allow for a variety of error terms to be calculated, from which the tunable coefficients are updated so as to iteratively minimize the error terms and simultaneously tune the equalizer to more accurately compensate for the degrading effects of the channel.Type: GrantFiled: March 25, 2013Date of Patent: April 21, 2015Assignee: Micron Technology, Inc.Inventor: Timothy Hollis
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Patent number: 9014249Abstract: A communications receiver includes an antenna, and a burst signal acquisition circuit coupled to the antenna to detect a burst signal received over a wireless communications channel. The burst signal has a burst structure that includes channel-corrupted known preamble bits, channel-corrupted known probe bits and channel-corrupted unknown data bits. A channel estimator is coupled to the burst signal acquisition circuit to generate a-priori a gain vector based on uncorrupted known probe bits, and to perform a recursive least squares (RLS) operation to determine an impulse response of the wireless communications channel based on the channel-corrupted known probe bits and the gain vector. A maximum likelihood sequence estimator (MLSE) or equalizer is coupled to the channel estimator and the burst signal acquisition circuit.Type: GrantFiled: November 2, 2012Date of Patent: April 21, 2015Assignee: Harris CorporationInventors: Joseph B Shaver, John Wesley Nieto, Michael Patrick Snook
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Patent number: 9009761Abstract: A system and method for wirelessly transmitting audiovisual information. Training information may be stored in a memory. A plurality of packets may be generated, including the training information. The plurality of packets may also include audiovisual information. The plurality of packets may include first information identifying a first training pattern of a plurality of possible training patterns. The first training pattern may specify one or more locations of the training information in the plurality of packets. The first information may be usable by a receiver to determine the first training pattern of the plurality of possible training patterns. The plurality of packets may be transmitted in a wireless manner.Type: GrantFiled: November 12, 2013Date of Patent: April 14, 2015Assignee: Coherent Logix, IncorporatedInventors: Kevin A. Shelby, Peter J. Nysen, Michael B. Doerr
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Publication number: 20150092828Abstract: A system and method consistent with the present disclosure includes determining a jitter tolerance of a particular lane of a communication link corresponding to each of a plurality of equalization coefficients. Further, determining a particular equalization coefficient of the plurality of equalization coefficients that provides a maximum jitter tolerance. Next, using the particular equalization coefficient for the particular lane of the communication link during operation based on determining the particular equalization coefficient which provides the maximum jitter tolerance.Type: ApplicationFiled: September 27, 2013Publication date: April 2, 2015Inventors: Nathaniel L. Desimone, Theodore Z. Schoenborn, Earl Wight, Duane Heller, Maria F. Pineda
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Patent number: 8995510Abstract: A portion of a signal under test corresponding to a portion of interest in an eye pattern is easily identified. An eye pattern display area displays an eye pattern that is derived from sample data of a signal under test in a bitmap form and shows frequency information with colors or brightness. A user selects an arbitrary point on the eye pattern display area with a cross-hair shaped mouse cursor, by manipulating a mouse. Thereafter, a waveform passing through the selected point is discriminably displayed, for example, with highlighted display on the eye pattern. Further, the corresponding portion of a waveform in the waveform display area is distinguishably displayed, such as with a highlighted display.Type: GrantFiled: March 25, 2008Date of Patent: March 31, 2015Assignee: Tektronix, Inc.Inventor: Toshiaki Obata
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Patent number: 8995512Abstract: Receivers (500) and methods of adaptively adjusting the receivers based on a received interferer are described. The peak-to-average ratio of a received signal is used to determine the type of interferer. The ratio and interferer type, in addition to the type of on-channel signal, are used to select parameters to adjust the decay time of a peak detector (516), and the threshold and hysteresis of a comparator (518). The peak detector (516) and comparator (518) are used to generate an off-channel flag that indicates the presence of a relatively strong interferer to other modules in the receiver (500). If valid data is not present a default set of parameters is provided. The ratio is determined by dividing the maximum peak over the average or a range of ratios is determined by comparing a scaled value of the average to different scaled values of the peak.Type: GrantFiled: September 2, 2011Date of Patent: March 31, 2015Assignee: Motorola Solutions, Inc.Inventors: Moshe Ben Ayun, Ricardo Franco, Ovadia Grossman, Mark Rozental, Uri Vallach
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Patent number: 8989245Abstract: A system and method are provided for calibrating the IQ-imbalance in a low-IF receiver. A Test Signal can be generated in a mirror frequency and conveyed to the receiver. The power of the signal produced in the receiver from the conveyed Test Signal can be measured. In the absence of an IQ-imbalance, the Test Signal can be completely eliminated in the receiver and the corresponding measured power of the produced signal can be minimized. Accordingly, a two dimensional algorithm is described for calibrating a receiver and correcting the IQ-imbalance by adjusting the phase and gain difference between the I and Q channels in the receiver based on the measured power of the signal produced in the receiver.Type: GrantFiled: August 6, 2013Date of Patent: March 24, 2015Assignee: SiTune CorporationInventors: Saeid Mehrmanesh, Vahid Mesgarpour Toosi, Mahdi Khoshgard
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Patent number: 8989253Abstract: A technique for a reconditioning equalizer filter for non-constant envelope signals is described. The input to a transmitter chain is modified by a reconditioning equalizer filter, prior to being applied to the transmitter. The reconditioning equalizer filter modifies and smoothens the amplitude of the signal. The modified and smoothened signal has its peaks reduced which results in lower Crest Factor. The input to the reconditioning equalizer filter could be a baseband, intermediate frequency (IF) or radio frequency (RF) signal. When the signal is an IF or RF signal, it needs to be down-converted to baseband before being applied to the reconditioning equalizer filter. The reconditioning equalizer filter could be performed in a digital or analog domain.Type: GrantFiled: June 17, 2014Date of Patent: March 24, 2015Assignee: Altera CorporationInventor: Kiomars Anvari
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Patent number: 8971210Abstract: A configurable network adapter has N analog front ends, each generating a receiver output and a transmitter input. In a first mode of operation, the analog front end receiver outputs are coupled to a MIMO equalizer, which is coupled to an outer receiver and to a first MAC input, with the first MAC having an output coupled to an outer transmitter, a MIMO modulator, and to the analog front end transmitter inputs. In a second mode of operation, one or more of the analog front ends is directed to a SISO modulator fed by a second outer transmitter coupled to a second MAC transmitter output. An associated one or more of the analog front end receivers is coupled to a SISO equalizer, and thereafter to an outer receiver and to the second lower MAC, thereby providing a first mode for a single MIMO adapter and a second mode for a MIMO plus independent PAN interface.Type: GrantFiled: May 23, 2011Date of Patent: March 3, 2015Assignee: Redpine Signals, Inc.Inventors: Partha Sarathy Murali, Logeshwaran Vijayan
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Patent number: 8958471Abstract: Requests are identified for equalization coefficients and a plurality of coefficient selections are tracked relating to the requests. A matrix is maintained within a grid space that is to represent the coefficients, the matrix representing one or more of the coefficient selections. The matrix is adjusted within the grid space to obtain an adjusted matrix that is to accommodate selection of a particular coefficient outside the matrix. A final coefficient can be selected based on the adjusted matrix.Type: GrantFiled: March 15, 2013Date of Patent: February 17, 2015Assignee: Intel CorporationInventor: Bruce A. Tennant
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Patent number: 8938037Abstract: A circuit for reducing phase errors in a digital communication systems signal is provided. The circuit comprises a demodulator block, a feed-forward path, a feed-back path, and a slicer. The demodulator block generates a plurality of samples from the signal and determines for each sample a corresponding phase error. The feed-forward path is configured to reduce in the signal a high frequency component of the phase errors. The feed-back path configured to reduce in the signal a low frequency component of the phase errors. The slicer selectively forwards phase errors to the feed-forward path or the feed-back path based on a respective magnitude of the phase error when operating in a decision-directed mode.Type: GrantFiled: March 13, 2013Date of Patent: January 20, 2015Assignee: PMC-Sierra US, Inc.Inventors: Saeed Fard, Sean Gibb, Peter Graumann, Siavash Sheikh Zeinoddin
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Patent number: 8934526Abstract: Methods and apparatus adapting equalizers for compensating for signal distortion of a received digital signal are disclosed. The method comprises deriving equalizer settings for a received signal, determining at least one signal parameter of said received signal; and storing the derived equalizer settings together with an indication of the signal parameter. The signal parameter could, for instance, comprise the data rate of the signal. If the signal parameter changes the equalizer is configured to use any stored settings which are appropriate for the new signal parameter. Thus, rather than start an entirely new equalizer adaptation routine every time the signal parameter changes the equalizer will use any stored settings which are appropriate for the changed parameter.Type: GrantFiled: June 28, 2010Date of Patent: January 13, 2015Inventors: Miguel Marquina, Chris Born, Ben Willcocks, Andrew Sharratt, Allard Van Der Horst
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Patent number: 8929428Abstract: Embodiments are directed to feed-forward equalization. In some embodiments, a first circuit is configured to receive a signal transmitted over a channel as a differential pair, and a second circuit is configured to mirror the signal as at least a pre-cursor component comprising a first transistor of a first type of technology, a cursor component comprising a second transistor of a second type of technology, and a post-cursor component comprising a third transistor of the first type of technology.Type: GrantFiled: October 30, 2012Date of Patent: January 6, 2015Assignee: International Business Machines CorporationInventors: Pier Andrea Francese, Thomas Toifl
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Patent number: 8923433Abstract: An equalizer provided in a digital transmitter compensates for attenuation in a signal channel to a digital receiver. The equalizer generates signal levels as a logical function of bit history to emphasize transition signal levels relative to repeated signal levels. The preferred equalizer includes an FIR transition filter using a look-up table. Parallel circuits including FIR filters and digital-to-analog converters provide a high speed equalizer with lower speed circuitry. The equalizer is particularly suited to in-cabinet and local area network transmissions where feedback circuitry facilitates adaptive training of the equalizer.Type: GrantFiled: February 3, 2014Date of Patent: December 30, 2014Assignee: Massachusetts Institute of TechnologyInventor: William J. Dally
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Patent number: 8923416Abstract: Systems and methods for implementing symbol-level repetition coding in power line communications (PLC) are described. In some embodiments, these systems and methods may provide reliable communication in severe channel environments of PLC networks, at least in part, by changing the forward error correction (FEC) used by various devices operating within current PLC systems. For example, a method may include receiving a PLC signal and applying convolutional encoding to the received signal, the convolutional encoding producing an encoded signal. The method may also include performing a subcarrier modulation operation upon the encoded signal, the subcarrier modulation operation producing a modulated signal. The method may further include applying symbol-level repetition coding to the modulated signal, the symbol-level repetition coding producing a repetitious signal. In some cases, one or more distinct repetition patterns may be applied to different symbols or portions thereof.Type: GrantFiled: October 6, 2011Date of Patent: December 30, 2014Assignee: Texas Instruments IncorporationInventors: Il Han Kim, Badri N. Varadarajan, Anand G. Dabak
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Patent number: 8923454Abstract: A method, an apparatus and a system for eliminating aliasing noise in a multi-carrier modulation system are disclosed. The method includes: acquiring a first power spectrum density template; acquiring information of in-band subcarriers whose aliasing noise is greater than background noise, and acquiring a difference between the aliasing noise and the background noise of the in-band subcarriers; adjusting the first power spectrum density template according to the information of the in-band subcarriers and the corresponding difference to obtain a second power spectrum density template; and sending signals according to the second power spectrum density template. The method, the apparatus, and the system disclosed herein eliminate the aliasing crosstalk noise, improve the performance and stability of in-band services without involving upgrade or modification of the Customer Premises Equipment (CPE), and are easy to implement.Type: GrantFiled: January 19, 2012Date of Patent: December 30, 2014Assignee: Huawei Technologies Co., Ltd.Inventors: Huijian Bo, Tao Wu, Yongjun Zhang
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Patent number: 8917800Abstract: A mechanism is provided for dynamically adjusting DC offset at the time of deviation from DC balance ½ (DC level) in a data pattern including long-period consecutive bits generating DC offset in a section of data. A receiver circuit unit of an LSI having a serializer/deserializer arrangement for performing high-speed serial transmission includes an offset adjusting circuit. The offset adjusting circuit calculates DC balance in an arbitrary section of data by averaging received serial data. Based on comparison between a DC level and the DC balance obtained by averaging the received data, offset is shifted toward the H side when the DC balance exists on the H side from the DC level, and shifted toward the L side when the DC balance exists on the L side.Type: GrantFiled: August 10, 2013Date of Patent: December 23, 2014Assignee: Hitachi, Ltd.Inventors: Akira Matsumoto, Naoki Mori, Takashi Yagi
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Patent number: 8917803Abstract: Circuits and methods characterize a receiver. The circuit includes a decision feedback equalizer (DFE) circuit, a clock and data recovery (CDR) circuit, a data checker, and an eye-scan controller. The DFE circuit generates a filtered signal from the communication signal. The filtered signal is a sum of the communication signal and a variable weighting of a symbol recently sampled from the filtered signal. The CDR circuit samples a sequence of sampled symbols from the filtered signal. The CDR circuit samples the filtered signal at a variable phase relative to a clock signal. The data checker generates an indication of an error in the sequence of sampled symbols. The eye-scan controller varies the variable weighting and the variable phase through multiple value combinations. The eye-scan controller checks for the indication of the error for each of the value combinations.Type: GrantFiled: May 3, 2011Date of Patent: December 23, 2014Assignee: Xilinx, Inc.Inventors: Santiago G. Asuncion, Mustansir Fanaswalla, Brandon L. Fernandes, Vaibhav Kamdar, Ray L. Jacinto
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Patent number: 8902964Abstract: Methods and apparatus for provision of equalization effort-balancing of transmit (TX) Finite Impulse Response (FIR) and receive (RX) Linear Equalizer (LE) or RX Decision Feedback Equalizer (DFE) structures in high-speed serial interconnects are described. In some embodiments, data corresponding to a plurality of transmit equalization values and a plurality of receive equalization values for each lane of a link having a plurality of lanes is detected. At least one of the plurality of the transmit equalization values and at least one of the plurality of the receive equalization values are selected for each lane of the plurality of lanes of the link based on detection of saturation in a Decision Feedback Equalizer (DFE) tap of a corresponding lane of the link. Other embodiments are also claimed and/or disclosed.Type: GrantFiled: September 29, 2012Date of Patent: December 2, 2014Assignee: Intel CorporationInventors: Manuel A. Aguilar-Arreola, Eric J. Msechu
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Patent number: 8891710Abstract: A method of channel estimation includes receiving a signal after transmission over a media having a plurality of sub-carriers in a frequency band. The signal is preprocessed including performing a fast Fourier transform (FFT) to generate a plurality of frequency-domain samples. Channel estimating is applied to the plurality of frequency-domain samples using (i) least squares (LS) estimation, wherein the LS estimation generates intermediate LS channel estimates for each of the sub-carriers, and (ii) frequency-domain filtering and scaling the intermediate LS channel estimates. The frequency-domain filtering uses a common frequency-domain filter consisting of a single filter coefficient vector having a plurality of frequency-domain filter coefficients to generate refined channel estimates for each of the plurality of sub-carriers.Type: GrantFiled: August 2, 2012Date of Patent: November 18, 2014Assignee: Texas Instruments IncorporatedInventor: June Chul Roh
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Patent number: 8879615Abstract: An equalization adaptation circuit comprises an equalizer, a transition determination circuit, a phase error circuit, a sequence recovery circuit, a phase error accumulator circuit, a transition accumulator circuit, and a controller circuit. The equalizer has adjustable parameters. The transition determination circuit determines observed transitions in an equalized signal output from the equalizer. A phase error circuit determines phase errors of the observed transitions. A sequence recovery circuit generates recovered digital data sequences. A phase error accumulator circuit accumulates the phase errors in respective association with pre-defined patterns matching the recovered digital data sequences containing observed transitions corresponding to the phase errors. A transition accumulator circuit accumulates a number of the observed transitions. A controller circuit controls the adjustable parameters of the equalizer based upon the accumulated phase errors and number of observed transitions.Type: GrantFiled: March 14, 2013Date of Patent: November 4, 2014Assignee: PMC-Sierra US, Inc.Inventor: Mathieu Gagnon
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Patent number: 8873608Abstract: Described are methods of determining imbalance in an IQ modulator. Example methods include applying a set of at least three test signals to the I channel and Q channel to generate an output, then receiving output from a frequency measuring device coupled to the IQ modulator. Some of the set of test signals may be substantially different than other test signals in the set. After the frequency specific output is received, the method measures one or more values and derives the imbalance in the IQ modulator from the measured values. Embodiments also include adjusting parameters of the test signals until a minimum distance is measured. A device is also described, which includes a test signal generator, an output analyzer, and a minimizer structured to cause the test signal generator to generate a set of test signals that cause a distance measured in the output to be a minimum distance.Type: GrantFiled: November 21, 2012Date of Patent: October 28, 2014Assignee: Tektronix, Inc.Inventor: Zoltan D. Azary
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Patent number: 8867673Abstract: A method for quantizing decision metrics (e.g., log likelihood ratios (LLRs)) for reduction of memory requirements in wireless communication is described. The method includes selecting a quantization algorithm. The quantization algorithm may be selected as a function of a characteristic of a decision metric representative of a transport block received over a communication channel, a characteristic of the transport block, or a condition of the communication channel. The method further includes quantizing the decision metric using the selected quantization algorithm to generate at least one quantized decision metric representative of the transport block. The method further includes storing the quantized decision metric and an indicia of the selected quantization algorithm to enable recovery of the decision metric representative of the transport block prior to decoding.Type: GrantFiled: July 12, 2011Date of Patent: October 21, 2014Assignee: QUALCOMM IncorporatedInventors: Thomas B. Wilborn, Brian C. Banister, Sungho Yun, Supratik Bhattacharjee, Inyup Kang
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Patent number: 8867413Abstract: A method of pre-equalizing a data signal transmitted in frequency division duplex includes receiving via an originating reference antenna a first pilot sequence transmitted by a destination antenna through a first channel, and estimating a first impulse response of the first channel; receiving via a destination antenna a second pilot sequence transmitted by an originating antenna through a second channel, and estimating a second impulse response of the second channel; receiving, via the reference antenna, a third pilot sequence modulated by the second impulse response and transmitted by the destination antenna, and estimating a combined impulse response of the first and second channels in succession; time reversing the combined impulse response; combining the time-reversed combined impulse response and the first impulse response; re-iterating the steps for a portion of the destination and originating antennas; and determining pre-equalization coefficients for the data signal from a set of the impulse responseType: GrantFiled: April 30, 2010Date of Patent: October 21, 2014Assignee: France TelecomInventors: Dinh Thuy Phan Huy, Jean-Marie Chaufray
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Patent number: 8867599Abstract: Transmissions from mid-bus test equipment to a first device and from a second device to the mid-bus test equipment are equalized. Equalization instructions are passed from the first device through the mid-bus test equipment to the second device. The mid-bus test equipment changes the quality of transmissions sent to the first device in order to steer the first device to produce equalization instructions that will produce optimized transmissions from the mid-bus test equipment to the first device and from the second device to the mid-bus test equipment.Type: GrantFiled: February 11, 2013Date of Patent: October 21, 2014Assignee: SerialTek, LLCInventors: Dale T Smith, Eric J Lanning
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Patent number: 8861580Abstract: Methods and apparatus are provided for determining one or more channel compensation parameters based on data eye monitoring. According to one aspect of the invention, a method is provided for evaluating the quality of a data eye associated with a signal. The received signal is sampled for a plurality of different phases, for example, using at least two latches, and the samples are evaluated to identify when the signal crosses a predefined amplitude value, such as a zero crossing. It is determined whether the points of predefined amplitude crossing satisfy one or more predefined criteria. One or more parameters of one or more channel compensation techniques can optionally be adjusted based on a result of the determining step. One or more parameters of an adjacent transmitter can also be adjusted to reduce near end cross talk based on a result of the determining step.Type: GrantFiled: May 16, 2006Date of Patent: October 14, 2014Assignee: Agere Systems LLCInventors: Christopher J. Abel, Mohammad S. Mobin, Gregory W. Sheets, Lane A. Smith
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Patent number: 8861575Abstract: A system and apparatus are disclosed for a method and apparatus for equalizing signals. An apparatus that incorporates teachings of the present disclosure may include, for example, an equalizer (100) having a channel estimation calculator (102) for calculating a time domain channel estimation from a baseband signal, an FFT processor (104) for translating the time domain channel estimation to a frequency domain channel estimation, a tap weight calculator (106) for calculating a frequency domain tap weight according to the frequency domain channel estimation, an inverse FFT processor (108) for translating the frequency domain tap weight calculation to a time domain tap weight calculation, and a filter (110) for equalizing the baseband signal according to the time domain tap weight calculation.Type: GrantFiled: November 15, 2012Date of Patent: October 14, 2014Assignee: AT&T Intellectual Property I, LPInventor: Arunabha Ghosh
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Patent number: 8855180Abstract: The disclosure relates to a receiver system that employs multiple instances of a DC compensation system to reduce DC offsets in a receiver path. The receiver has a receiver front end configured to receive an RF input signal and to operate on the RF input signal according to a plurality of receiver states to generate a baseband signal having a DC offset that is based upon the plurality of receiver states. A DC offset compensation circuit implements a plurality of instances of DC offset compensation components that respectively generate an estimated DC offset corresponding to a receiver state. A controller controls the receiver state of the receiver front end and operates the DC offset elimination circuit to selectively apply one of the plurality of DC compensation components to the corresponding baseband signal based upon the receiver state.Type: GrantFiled: October 31, 2012Date of Patent: October 7, 2014Assignee: Intel Mobile Communications GmbHInventors: Peter Noest, Peter Bode, Thorsten Tracht, Clemens Troebinger
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Patent number: 8855186Abstract: Computationally efficient methods and related systems, for use in a test and measurement instrument, such as an oscilloscope, optimize the performance of DFEs used in a high-speed serial data link by identifying optimal DFE tap values for peak-to-peak based criteria. The optimized DFEs comply with the behavior of a model DFE set forth in the PCIE 3.0 specification.Type: GrantFiled: December 15, 2011Date of Patent: October 7, 2014Assignee: Tektronix, Inc.Inventor: Kan Tan
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Patent number: 8855184Abstract: Efficient decoding in IEEE 802.11ah networks can be achieved by transmitting the signal (SIG) preamble field without interleaving bits within the SIG field. This may allow channel equalization and decoding steps to be performed contemporaneously upon reception of the frame, which allows for the implementation of non-linear channel equalization techniques (e.g., maximum likelihood (ML) equalization, etc.Type: GrantFiled: January 11, 2013Date of Patent: October 7, 2014Assignee: Futurewei Technologies, Inc.Inventors: Junghoon Suh, Kwok Shum Au, Osama Aboul-Magd, Tianyu Wu
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Patent number: 8842722Abstract: Equalization techniques are provided for high-speed data communications and, more specifically, DFE (decision feedback equalizer) circuits and methods are provided which implement a high-order continuous time filter in a DFE feedback path to emulate structured elements of a channel response.Type: GrantFiled: August 22, 2012Date of Patent: September 23, 2014Assignee: International Business Machines CorporationInventors: Timothy O. Dickson, Rui Yan Matthew Loh
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Publication number: 20140269881Abstract: Techniques for adaptive backchannel equalization. A total equalization value is determined over a preselected training period. A total balance equalization value is determined over the preselected training period. A transmitter equalization coefficient is determined based on the total equalization value and the total balance equalization value. Data is transmitted over a serial link using the transmitter equalization coefficient.Type: ApplicationFiled: May 20, 2013Publication date: September 18, 2014Inventors: YUN HE, SANJIB SARKAR
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Publication number: 20140269880Abstract: A receiver performs interference mitigation under blind or semi-blind conditions using diversity present in the signal of interest or in the interferer. A first path interference mitigation procedure extracts training information from received signals, performs interference mitigation on the training information and estimates the channel. The second path interference mitigation procedure uses data extracted from the received signal and the channel estimate to perform interference mitigation. Each interference mitigation process can take the form of a lossy compression followed by decompression.Type: ApplicationFiled: March 15, 2013Publication date: September 18, 2014Inventor: Fernando Lopez de Victoria
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Publication number: 20140241411Abstract: A system and method for link training of a backplane physical layer device operating in simplex mode. In one embodiment of the present invention, a backplane training system includes a backplane device coupled to a first end of a backplane and at least one retimer device at a second end of the backplane. During a training process, a receiving device is configured to forward a training frame (e.g., DME frame) to a second device for use by a transmitter in the second device.Type: ApplicationFiled: March 28, 2013Publication date: August 28, 2014Applicant: Broadcom CorporationInventor: Ali Ghiasi
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Publication number: 20140241397Abstract: According to one embodiment, an electronic thermometer includes a temperature sensing unit, a conversion unit, an FSK modulation unit, and a transmission unit. The temperature sensing unit detects the temperature of a subject. The conversion unit converts a result detected by the temperature sensing unit to a digital signal. The FSK modulation unit converts the digital signal from the conversion unit to an FSK modulation signal. The transmission unit outputs a transmission signal including a pilot signal having a frequency assigned to the FSK (frequency shift keying) modulation signal and the FSK modulation signal subsequent to the pilot signal.Type: ApplicationFiled: February 25, 2014Publication date: August 28, 2014Applicant: Kabushiki Kaisha ToshibaInventors: Kazunori Hashimoto, Hiromi Sakata, Hisashi Yoshikawa, Kumiko Yamato
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Patent number: 8817860Abstract: Systems and methods for performing phase tracking scheme for an Analog to Digital converter based tuner. In many embodiments, a phase tracking scheme is used that includes a phase locked loop that corrects the phase of the output signals and an amplitude modulation compensator that modulates the amplitude of the output digital signals to compensate for phase noise based upon the received output digital signals.Type: GrantFiled: September 10, 2012Date of Patent: August 26, 2014Assignee: Entropic Communications, Inc.Inventor: Tommy Yu
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Publication number: 20140233627Abstract: An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.Type: ApplicationFiled: January 21, 2014Publication date: August 21, 2014Applicant: RAMBUS INC.Inventor: Robert E. Palmer
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Publication number: 20140226703Abstract: A wireless receiver includes an input module, a channel module, an equalizer module, and a decoder module. The input module receives a message over a wireless communication channel. The message includes a plurality of training fields and first data. The first data includes user data perturbed by the channel. The channel module generates a first matrix indicative of an estimation of properties of the channel. The channel module, as each of the plurality of training fields of the message is being received, recursively computes parameters for equalization based on the plurality of training fields, the first matrix, and a vector indicative of a substream signal-to-noise ratio. The equalizer module generates equalizer coefficients based on the parameters for equalization and applies the equalizer coefficients to the first data of the message to generate compensated first data. The decoder module decodes the compensated first data to recover the user data.Type: ApplicationFiled: April 15, 2014Publication date: August 14, 2014Applicant: MARVELL WORLD TRADE LTD.Inventor: Konstantinos Sarrigeorgidis
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Patent number: 8797837Abstract: Systems and methods for multiplexing signals are disclosed. In one embodiment, the method comprises receiving a first signal having at least a real component, receiving a second signal having at least a real component, generating an in-phase signal based, at least in part, on the first signal, the in-phase signal being real in a first domain, generating a quadrature signal based, at least in part, on the second signal, the quadrature signal being imaginary in the first domain, adding the in-phase signal and the quadrature signal to generate a multiplexed signal, and transmitting the multiplexed signal.Type: GrantFiled: September 2, 2009Date of Patent: August 5, 2014Assignee: Samsung Electronics Co., Ltd.Inventors: Xiaochen Li, Chiu Ngo
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Patent number: 8792396Abstract: Pre-equalizing a data signal transmitted in frequency division duplex by an originating entity having a set of originating antennas to a destination entity having a set of destination antennas, including: transmitting a first pilot by a destination antenna; the originating entity estimating a first impulse response of a first channel; an iterative step including an originating antenna transmitting a second pilot modulated by the first impulse response; the destination entity estimating and time reversing a combined impulse response of the first and second channels; the destination antenna transmitting a third pilot modulated by the time-reversed response; estimating a composite response of the channels; re-iterating the iterative step for some originating antennas; and re-iterating the steps of transmitting a first pilot, estimating the first response, and the iterative step for some destination antennas; and determining pre-equalization coefficients for the data signal from a combination of a set of compositType: GrantFiled: April 30, 2010Date of Patent: July 29, 2014Assignee: France TelecomInventors: Dinh Thuy Phan Huy, Jean-Marie Chaufray
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Patent number: 8787438Abstract: A technique for a reconditioning equalizer filter for non-constant envelope signals is described. The input to a transmitter chain is modified by a reconditioning equalizer filter, prior to being applied to the transmitter. The reconditioning equalizer filter modifies and smoothens the amplitude of the signal. The modified and smoothened signal has its peaks reduced which results in lower Crest Factor. The input to the reconditioning equalizer filter could be a baseband, intermediate frequency (IF) or radio frequency (RF) signal. When the signal is an IF or RF signal, it needs to be down-converted to baseband before being applied to the reconditioning equalizer filter. The reconditioning equalizer filter could be performed in a digital or analog domain.Type: GrantFiled: December 23, 2013Date of Patent: July 22, 2014Assignee: Altera CorporationInventor: Kiomars Anvari
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Patent number: 8787436Abstract: A communication device is disclosed including: an analog-to-digital converter (ADC) for converting an analog input signal into a digital input signal; an equalizer module coupled with the ADC for processing the digital input signal to generate an equalized signal; a data slicer coupled with the equalizer module for generating an output signal based on the equalized signal; and a control unit coupled with the equalizer module and the data slicer; wherein the control unit or the equalizer module preserves at least one signal equalizing parameter of the equalizer module before the equalizer module enters power saving mode, and the equalizer module loads the at least one signal equalizing parameter to operate when the communication device receives a predetermined control signal.Type: GrantFiled: December 23, 2011Date of Patent: July 22, 2014Assignee: Realtek Semiconductor Corp.Inventors: Liang-Wei Huang, Fang-Ru Wang, Ting-Fa Yu, Chien-Sheng Lee
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Patent number: RE45136Abstract: A telephone line status notification system including at least one telephone line having a status, a communications network, at least one communications terminal which is connectable to the communications network and which is employable by a seeking user to communicate via the communications network a status request concerning the status of the at least one telephone line, apparatus for processing the status request the apparatus for processing is connectable to the communications network for receiving the status request from the seeking user therethrough and communicating the request, and apparatus for acquiring the status of the at least one telephone line, the apparatus for acquiring is in communication with the apparatus for processing for receiving the status request therefrom, and the apparatus for acquiring is connectable to the communications network for communicating the status via the communications network.Type: GrantFiled: August 17, 2012Date of Patent: September 16, 2014Assignee: Facebook, Inc.Inventors: Joseph Vardi, Arie Vardi, Joseph Vigiser, Yair Goldfinger