Having Specific Distortion, Noise Or Other Interference Prevention, Reduction Or Compensation Patents (Class 329/318)
  • Patent number: 10462797
    Abstract: Methods and apparatus for using communications channels corresponding to frequency bands subject to cellular network, e.g., LTE, interference and/or other interference are described. The methods are well suited for use of cable networks where communications over a coax cable or via cable device may be subject to LTE interference. In various embodiments data traffic is classified based on whether the traffic corresponds to a protocol that supports a retry communications mechanism in the event of a communication error, the type of traffic data and/or the priority of the traffic data. In some embodiments data being communicated using a protocol which supports a retry mechanism are routed over channels subject to interference even if, in some cases, the packets correspond to data which has a higher priority or QoS requirements than packets, e.g., best effort packets, which are transmitted using a protocol that does not support a packet retry mechanism.
    Type: Grant
    Filed: July 26, 2018
    Date of Patent: October 29, 2019
    Assignee: Time Warner Cable Enterprises LLC
    Inventors: Louis D. Williamson, Michael Kelsen
  • Patent number: 10312954
    Abstract: A computer-implemented method to identify RPI (Radio Frequency Interference) in a spectrogram includes dividing, by a matrix module of a computer processor, the spectrogram into a plurality of blocks, each block comprising a matrix of data points. The method includes applying, by a masking module of the computer processor, a plurality of matrix pooling functions to each block, the plurality of matrix pooling functions configured to produce a plurality of summarized pools. The method includes creating, by a masking module of the computer processor, a line mask for each of the pools and creating, by the masking module, an RPI mask based at least on the line masks, the RPI mask being indicative of RPI.
    Type: Grant
    Filed: December 25, 2017
    Date of Patent: June 4, 2019
    Assignee: International Business Machines Corporation
    Inventors: Melvin Mathew Varughese, Francois P S Luus, Ismail Y Akhalwaya, Arun Aniyan, Monica Obrocka
  • Patent number: 10091795
    Abstract: Methods and apparatus for using communications channels corresponding to frequency bands subject to cellular network, e.g., LTE, interference and/or other interference are described. The methods are well suited for use of cable networks where communications over a coax cable or via cable device may be subject to LTE interference. In various embodiments data traffic is classified based on whether the traffic corresponds to a protocol that supports a retry communications mechanism in the event of a communication error, the type of traffic data and/or the priority of the traffic data. In some embodiments data being communicated using a protocol which supports a retry mechanism are routed over channels subject to interference even if, in some cases, the packets correspond to data which has a higher priority or QoS requirements than packets, e.g., best effort packets, which are transmitted using a protocol that does not support a packet retry mechanism.
    Type: Grant
    Filed: October 24, 2016
    Date of Patent: October 2, 2018
    Assignee: Time Warner Cable Enterprises LLC
    Inventors: Louis D. Williamson, Michael Kelsen
  • Patent number: 9841474
    Abstract: A method for controlling a signal with a plurality of independent components is provided. The signal is fed as an input signal via an input path to a control path that supplies an output signal. The output signal is fed via an output path to a control apparatus controlling the input signal. A coupling signal is determined in a coupling determination apparatus. On the basis of the coupling signal, the independent components are decoupled in a decoupling apparatus, as a result of which, a decoupled output signal is generated. Components of the decoupled output signal are decoupled from the components of the input signal. The decoupled output signal is fed as a control variable to the control apparatus. The control apparatus controls each independent component separately on the basis of a desired signal with a diagonal controller and outputs the input signal as a manipulated variable.
    Type: Grant
    Filed: August 30, 2011
    Date of Patent: December 12, 2017
    Assignee: Siemens Aktiengesellschaft
    Inventors: Klaus Huber, Clemens Jungkunz, Sebastian Martius, Martin Nisznansky, Markus Vester
  • Patent number: 9729378
    Abstract: A system and method involve receiving, at a processor, a phase modulated signal such as an optical or electromagnetic signal, using one or more samples of an in-phase component I(t) and a quadrature component Q(t) of the received phase modulated signal to generate, at the processor, a processed signal using the equation [A?B×I(t)]×Q(t), where A and B are numerical parameters, and inputting the processed signal into a receiver operatively connected to the processor. The processed signal may be filtered prior to being input into the receiver. Parameters A and B may be selected to vary complexity and performance of the receiver while controlling distortion for different modulation indices.
    Type: Grant
    Filed: June 29, 2015
    Date of Patent: August 8, 2017
    Assignee: THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY
    Inventor: Ahsen Ahmed
  • Patent number: 9614558
    Abstract: A device and method for unwrapping phase samples of a burst signal. The device generates a set of vectors including phase samples. A first mean and a first variance of the vectors is computed, and a set of unwrapped phase samples of the burst signal are computed by rotating phase samples of the vector having a smallest first variance by a first rotation amount. The set of vectors is updated based on a new phase sample and a second mean and a second variance of the updated set of vectors is computed. Differences between unwrapped phase samples and a number of phase samples included in the vector having the smallest computed second variance are computed. A next unwrapped phase sample is generated by rotating the new phase sample by a second rotation amount corresponding to a median value of the computed differences.
    Type: Grant
    Filed: March 25, 2016
    Date of Patent: April 4, 2017
    Assignee: VT IDIRECT, INC.
    Inventors: Ronggang Qi, Baoyan Ding
  • Patent number: 9489055
    Abstract: A control panel comprising a plurality of hard key buttons which are arranged in different groups is suggested. A first group of buttons is assigned to select predefined scene settings. A second group of buttons is assigned to select signals for a currently broadcasted scene. A third group of buttons is assigned to select signals for a next scene which is selectable by operating a button of the first group. The hardware control panel provides an operating interface that matches with the workflow of TV productions. It enables context related direct access to all functionalities which are needed during the TV show. However, it does not provide access to those functionalities which are not needed in a specific scene. Hence, it significantly reduces or even prevents malfunctions during a TV production.
    Type: Grant
    Filed: February 2, 2014
    Date of Patent: November 8, 2016
    Assignee: Scalable Video Systems GMBH
    Inventors: Alfred Krug, Sven Papke
  • Patent number: 9398587
    Abstract: A method of and apparatus removing of a plurality of relatively narrow banded signals in a relatively wide banded input signal. The method involves and the apparatus provides for compressively sensing one relatively narrow banded signal in the relatively wide banded input signal and removing one relatively narrow banded signal from the relatively wide banded input signal before detecting and removing another relatively narrow banded signal in the relatively wide banded input signal, the step of and apparatus for compressing sensing occurring with respect to both (i) the input signal with the previously detected narrow banded signals removed therefrom and (ii) a frequency shifted version of (i).
    Type: Grant
    Filed: February 19, 2014
    Date of Patent: July 19, 2016
    Assignee: HRL Laboratories, LLC
    Inventors: Cathy (Xiangming) Kong, Kang-Yu Ni
  • Patent number: 9391625
    Abstract: A digitally controlled oscillator (DCO) modulation apparatus and method provides a wideband phase-modulated signal output. An exemplary modulator circuit uses an oscillator in a phase-locked loop. The circuit receives a wrapped-phase input signal, unwraps the wrapped-phase input signal to generate an unwrapped-phase signal, and differentiates the unwrapped-phase signal. The wrapped-phase input signal and the differentiated unwrapped-phase signal are both injected into a feedback loop of the modulator circuit. The feedback loop may include a multi-modulus frequency divider with a frequency divisor that is temporarily incremented or decremented to cancel out abrupt phase jumps associated with the wrapped-phase to unwrapped-phase conversion.
    Type: Grant
    Filed: March 24, 2015
    Date of Patent: July 12, 2016
    Assignee: INNOPHASE INC.
    Inventors: Yang Xu, Fa Foster Dai, Dongyi Liao
  • Patent number: 8792640
    Abstract: A digital data signal, such as a digital video signal, is intentionally pre-distorted before being sent over a network. In one embodiment, this pre-distortion may be performed in accordance with a pre-distortion pattern or algorithm which is shared with only intended receivers. The pre-distortion pattern may be used to vary the pre-distortion on a periodic basis, as frequently as on a symbol-by-symbol basis. The pre-distortion function may include distorting the phase and/or the amplitude of the digital signal's modulation.
    Type: Grant
    Filed: January 29, 2008
    Date of Patent: July 29, 2014
    Assignees: Sony Corporation, Sony Electronics Inc.
    Inventors: Kenichi Kawasaki, Robert Hardacker
  • Patent number: 8588353
    Abstract: In conventional radio frequency (RF) systems, transmitters will usually convert baseband signals to RF so as to be transmitted. As part of the conversion process, the transmitters will perform digital predistortion (DPD), which uses feedback from a power amplifier. However, there are usually mismatches between the in-phase (I) and quadrature (Q) paths within with feedback loop. Traditional IQ correction filters were ineffective at providing adequate compensation for these mismatches, but here a filter is provided that provides adequate out-of-band compensation by use of frequency selectivity.
    Type: Grant
    Filed: April 1, 2011
    Date of Patent: November 19, 2013
    Assignee: Texas Instruments Incorporated
    Inventors: Zigang Yang, Lars Jorgensen, Lei Ding
  • Patent number: 8532225
    Abstract: Receiver circuitry for processing a received Very Low Intermediate Frequency signal wherein the receiver circuitry comprises a main processing path. The main processing path comprises mixing circuitry arranged to mix a received VLIF signal with a frequency down conversion signal to produce a main path signal. The receiver circuitry further comprises a direct current cancellation path comprising mixing circuitry arranged to mix a DC element of the received VLIF signal with the frequency down conversion signal to produce a DC cancellation signal. The receiver circuitry still further comprises signal summing circuitry arranged to add the DC cancellation signal in anti-phase with the main path signal.
    Type: Grant
    Filed: March 19, 2008
    Date of Patent: September 10, 2013
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Conor O'Keeffe, Norman Beamish, Richard Verellen
  • Patent number: 8509328
    Abstract: Disclosed herein is a reception apparatus including: an acquisition section configured to acquire an orthogonal frequency division multiplexing signal composed resultingly of signals transmitted by the orthogonal frequency division multiplexing method from a plurality of transmission apparatuses; a correction value calculation block configured to calculate a correction value for correcting a drift amount of the orthogonal frequency division multiplexing signal using the phase of either a first pilot signal or a second pilot signal extracted from the acquired orthogonal frequency division multiplexing signal, the first pilot signal being obtained from pilot signals which are in phase with one another coming from the plurality of transmission apparatuses, the second pilot signal being acquired from pilot signals which are out of phase with one another coming from the plurality of transmission apparatuses; and a correction block configured to correct the drift amount of the orthogonal frequency division multiple
    Type: Grant
    Filed: July 15, 2010
    Date of Patent: August 13, 2013
    Assignee: Sony Corporation
    Inventors: Lachlan Bruce Michael, Yuken Goto, Kenichi Kobayashi
  • Patent number: 8509341
    Abstract: A communications device includes a modulator and a filter downstream therefrom and operable to generate an output wideband complex signal with a frequency notch therein. The filter includes a finite impulse response (FIR) filter with L taps to generate N output values, with L>N. A Fast Fourier Transform (FFT) block is downstream from the FIR filter and has a length N so that filter transition regions occur between frequency bins of the FFT block. A notching block is downstream from the FFT block to generate the frequency notch. An Inverse Fast Fourier Transform (IFFT) block is downstream from the notching block and has the length N.
    Type: Grant
    Filed: December 10, 2008
    Date of Patent: August 13, 2013
    Assignee: Harris Corporation
    Inventor: Mark Chamberlain
  • Patent number: 8503590
    Abstract: Preceding filters receive the inputs of a plurality of received signals associated respectively with a plurality of antennas. Subsequent filters band-limit the plurality of inputted received signals, respectively. A first combining unit derives a weight vector for the plurality of band-limited received signals and performs array synthesis on the plurality of band-limited received signals, using the derived weight vector. The second combining unit performs array synthesis on the plurality of inputted received signal signals, using the derived weight vector. A demodulator demodulates the array-synthesis result.
    Type: Grant
    Filed: May 25, 2010
    Date of Patent: August 6, 2013
    Assignees: Semiconductor Components Industries, LLC, Sanyo Semiconductor Co., Ltd.
    Inventors: Yuichiro Tuskamizu, Yoshiharu Doi, Keisuke Higuchi
  • Patent number: 8503577
    Abstract: In a wireless system including a wireless communication channel, a method for estimating a signal quality of a received signal includes the steps of receiving a signal from the wireless communication channel, the received signal including at least one field that is modulated and encoded in a substantially fixed manner, and generating at least one reference field based, at least in part, on the at least one field and on a channel estimation signal. The channel estimation signal is representative of at least one characteristic of the wireless communication channel. The method further includes the step of generating a signal quality estimate as a function of the at least one field in the received signal and the generated at least one reference field.
    Type: Grant
    Filed: July 17, 2003
    Date of Patent: August 6, 2013
    Assignee: Agere Systems LLC
    Inventors: Jan Boer, Bas Driesen, Ra'anan Gil, Kai Roland Kriedte
  • Patent number: 8390425
    Abstract: RFID readers, reader systems, and methods are provided that utilize double conversion for received tag response signals. A digitized signal is derived from the tag response signal by first shifting the response signal to about DC. The components of the digitized signal are then up converted and down converted and filtered such that only components around DC remain. The up converted and down converted signals may then be compared and one selected or the two combined after weighting to enhance demodulation and reduce circuit complexity.
    Type: Grant
    Filed: May 1, 2007
    Date of Patent: March 5, 2013
    Assignee: Impinj, Inc.
    Inventors: Scott Anthony Cooper, Kurt Eugene Sundstrom
  • Patent number: 8350665
    Abstract: RFID tags are commanded to generate a pilot tone in their backscatter. When the backscattered pilot tone is received in the reader, the pilot tone is used to estimate the tag period/frequency. Then, the estimate is used to seed and lock a symbol timing recovery loop, which provides a detected signal to one or more correlators for detecting the tag preamble. A delayed version of the received tag signal is compared against a baseline signal threshold established from the received signal to detect the pilot tone.
    Type: Grant
    Filed: February 28, 2012
    Date of Patent: January 8, 2013
    Assignee: Impinj, Inc.
    Inventors: Kurt E. Sundstrom, Scott A. Cooper, Amir Sarajedini, Aanand Esterberg, Todd E. Humes, Christopher J. Diorio
  • Patent number: 8290100
    Abstract: Techniques for detecting and mitigating interference are described. A device (e.g., a cellular phone) senses interference levels and digitally reconstructs the expected interference in the received signal. The device may correlate the reconstructed interference with the received signal and determine interference in the received signal based on correlation results. The device may adjust the operation of one or more circuit blocks (e.g., a mixer, an LNA, etc.) in a receiver based on the detected interference in the received signal. Alternatively or additionally, the device may condition the digital interference to obtain conditioned reconstructed interference matching the interference in the received signal and may then subtract the conditioned interference from the received signal.
    Type: Grant
    Filed: December 9, 2008
    Date of Patent: October 16, 2012
    Assignee: Qualcomm Incorporated
    Inventors: Christos Komninakis, Daniel F. Filipovic
  • Patent number: 8265206
    Abstract: A radio receiver which performs iterative decoding of a received signal is provided. The radio receiver comprises: a receiving unit receiving a signal on a symbol-by-symbol basis; a demodulation unit (303) demodulating the received signal; a last symbol timing generation unit (308) generating a last symbol timing signal on the basis of the signal demodulated by the demodulation unit (303); a modulation unit (304) modulating the signal demodulated by the demodulation unit (303); and a cancellation unit (306) cancelling an interference component of the received signal using a replica signal generated on the basis of the signal modulated by the modulation unit (304). The modulation unit (304) controls the timing of rearrangement of a data sequence on the basis of the timing of the last symbol. Thus, a radio receiver in which the receiving processing time is reduced can be provided.
    Type: Grant
    Filed: July 3, 2008
    Date of Patent: September 11, 2012
    Assignee: Panasonic Corporation
    Inventors: Hirohito Mukai, Hidekuni Yomo, Kiyotaka Kobayashi, Yoshinori Kunieda
  • Patent number: 8218687
    Abstract: A receiver estimates I/Q imbalance in I and Q input signals using circuitry to separate different frequency components of the I and Q input signals, and estimation circuitry arranged to estimate I/Q imbalance at the different frequency bands. The separating of the bands may be carried out in the frequency domain, and may involve combining corresponding values representing corresponding negative and positive frequency bands, and converting the separated frequency domain representations to a time domain representation before the estimation. The estimated imbalance may be used to correct the I and Q signals at the different frequency bands.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: July 10, 2012
    Assignee: ST-Ericsson SA
    Inventor: Anthony D. Sayers
  • Patent number: 8170151
    Abstract: A receiver includes a band-pass filter that limits a passband of an IF (Intermediate Frequency) signal, an FSK detector that detects the IF signal passing through the band-pass filter to generate a detection signal, and a control block that controls a modulation sensitivity of the FSK detector and a pass bandwidth of the band-pass filter, in which the control block controls the modulation sensitivity of the FSK detector according to the pass bandwidth of the band-pass filter.
    Type: Grant
    Filed: February 18, 2009
    Date of Patent: May 1, 2012
    Assignee: Renesas Electronics Corporation
    Inventor: Shigeya Suzuki
  • Patent number: 8160191
    Abstract: Embodiments of the invention are concerned with correction of quadrature errors associated with digital communications systems, and in particular in a wireless transmit chain in which an up-converter and a down-converter both have a direct conversion architecture. One embodiment comprises a correction network for correcting a difference between a transmission characteristic of an in-phase signal path and a transmission characteristic of a quadrature signal path, said quadrature signal path being for the transmission of in-phase and quadrature parts of a signal and the signal comprising frequency components within a base band, wherein the correction network comprises an in-phase input port, a quadrature input port, an in-phase output port and a quadrature output port, wherein each input port is connected to each output port by a digital filter network, the digital filter network comprising a set of filter tap coefficients and configuration means for configuring values of said set of filter tap coefficients.
    Type: Grant
    Filed: December 1, 2008
    Date of Patent: April 17, 2012
    Assignee: Rockstar Bidco LP
    Inventors: Paul Murray Row, Dorian Thomas Charles Davies
  • Patent number: 8120419
    Abstract: A type-A demodulator comprising a first rectifier configured to rectify a radio frequency (RF) signal received through an antenna and output a first voltage, a second rectifier configured to rectify the voltage of the RF signal received through the antenna and output a second voltage having a different voltage level than the first voltage, and a pause data detector configured to compare the first voltage with the second voltage and detect received pause data.
    Type: Grant
    Filed: March 12, 2010
    Date of Patent: February 21, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jong Pil Cho, Hyuk Jun Sung
  • Patent number: 8116395
    Abstract: An exemplary aspect of an embodiment of the present invention is a receiver comprises a subcarrier unit combination section that performs weighting corresponding to quality of each subcarrier with respect to each subcarrier relating to a received symbol, a symbol unit combination section that performs common weighting based on quality of the symbol with respect to each subcarrier, and a combination system switching unit that switches between use of the symbol unit combination section and the subcarrier unit combination section.
    Type: Grant
    Filed: October 16, 2008
    Date of Patent: February 14, 2012
    Assignee: Renesas Electronics Corporation
    Inventor: Takahiro Sato
  • Patent number: 8093765
    Abstract: Disclosed is an improved noise reducing apparatus using an anti-circuit, including a digital logic circuit and a digital anti-circuit corresponding to the digital logic circuit. The digital anti-circuit functions to cancel noise generated by the digital logic circuit. The anti-circuit includes logic to generate a similar number of switching edges as the logic circuit, where the anti-circuit edges are in the opposite direction as the logic circuit. The anti-circuit may have a circuit structure close to that of the noisy circuit, or can be formed of components different in structure but generating an output pattern similar to (and opposite from) the noisy circuit. In some embodiments, the differently structured components can include a state machine coupled to a memory or look-up-table.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: January 10, 2012
    Assignee: Cypress Semiconductor Corporation
    Inventor: Paul Beard
  • Patent number: 8073079
    Abstract: A threshold noise-canceling method comprising the steps of: receiving an angle-modulated signal; identifying in the angle-modulated signal potential threshold noise events that exceed a first threshold value; calculating average values of the phase of the angle-modulated signal before and after a potential threshold noise event; identifying every potential threshold noise event as a threshold noise event when the difference between the corresponding before and after average values of the phase is greater than a second threshold value; and canceling out each threshold noise event by adding to the phase of the angle-modulated signal a 2? phase shift of polarity opposite to that of the corresponding threshold noise event.
    Type: Grant
    Filed: October 20, 2008
    Date of Patent: December 6, 2011
    Assignee: The United States of America as represented by Secretary of the Navy
    Inventor: Ahsen Ahmed
  • Patent number: 8068531
    Abstract: A device and method for eliminating narrow-band interference by windowing in a spread spectrum system are disclosed. The method comprises extracting N sampling points of data to perform frequency spectrum transform each time and obtaining N points of data; updating control information, comparing the energy values of the N points with the threshold within the set time period to determine the number of narrow-band interference as well as the width and location of the interference; determining the corresponding frequency domain adjusting window based on the width and location of the narrow band interference, obtaining the points within the window and the adjusted values of those points; with regard to the transformed N points during interference elimination process, setting the energy values of the points within the window during the current time period and the last period as the corresponding adjusted values, outputting the points after frequency spectrum inverse transform.
    Type: Grant
    Filed: December 16, 2005
    Date of Patent: November 29, 2011
    Assignee: ZTE Corporation
    Inventors: Meng Zhao, Jiying Xiang, Chunbo Yao
  • Patent number: 8059739
    Abstract: A wireless communication device corrects data transmission errors caused by the simultaneous transmission of multiple streams of data in a Multiple-Input Multiple-Output (MIMO) network. The wireless communication device corrects data transmission errors by removing the signal contribution associated with one or more received signal components from a corresponding received composite signal, thus allowing the remaining components to be decoded relatively free from the signal contribution of the removed components. In one embodiment, the wireless communication device comprises a plurality of antennas and a baseband processor. The antennas are configured to receive a composite signal having a plurality of received signal components.
    Type: Grant
    Filed: June 5, 2006
    Date of Patent: November 15, 2011
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventor: Elias Jonsson
  • Patent number: 8026758
    Abstract: There is provided an FM demodulator comprising a transistor (Q323), a filter unit for producing first and second amplitude-modulated signals from a received frequency-modulated signal, wherein the filter unit is coupled to the switching transistor (Q323), and first and second diodes (D300) connected in opposite relationship for rectifying the first and second amplitude-modulated signals of the filter unit. The filter unit has an LC network and is so dimensioned that there is a linear relationship between the output voltage and the input frequency. The demodulator further has an operating point adjusting unit for adjusting an operating point of the transistor. The operating point adjusting unit (100) is adapted to effect operating point adjustment with a noise negative feedback.
    Type: Grant
    Filed: September 11, 2009
    Date of Patent: September 27, 2011
    Assignee: Sennheiser electronic GmbH & Co. KG
    Inventor: Frank Hagemeyer
  • Patent number: 7961040
    Abstract: A mixed-signal chip is described. The mixed-signal chip comprises a first portion of analog circuit and second portion of digital circuit, an on-chip precision oscillator residing on the first analog portion, the precision oscillator has a precision frequency; a first on-chip non-precision tunable oscillator from a first clock domain residing on the first analog portion, the first non-precision tunable oscillator has a first adjustable frequency; a noise detector for detecting a first noise in the first clock domain; a frequency adjusting register for storing a first desired frequency value of the first on-chip non-precision tunable oscillator, wherein the first desired frequency value is determined based on the first detected noise; a control circuit for adjusting the adjustable frequency of the first non-precision tunable oscillator to the first desired frequency value by using the precision frequency of the on-chip precision oscillator as a reference.
    Type: Grant
    Filed: August 22, 2008
    Date of Patent: June 14, 2011
    Assignee: OmniVision International Holding, Ltd.
    Inventor: Gang Xu
  • Patent number: 7864879
    Abstract: A system having a signal processor for detection of a signal type of a signal is disclosed. One embodiment includes a processor designed to determine a first variable which is characteristic of a first spectrum element of the signal spectrum, and to determine a second variable which is characteristic of a second spectrum element of the signal spectrum. A system is provided for determination of a ratio between the first variable and the second variable, and a detector which is designed to detect the signal type on the basis of the ratio.
    Type: Grant
    Filed: February 15, 2007
    Date of Patent: January 4, 2011
    Assignee: Infineon Technologies AG
    Inventors: Xiaofeng Wu, Martin Krueger
  • Patent number: 7844018
    Abstract: An OFDM telecommunications system includes a transmitter and a receiver. The receiver includes a canceller configured to reduce inter-carrier interference (ICI) in an OFDM symbol in the frequency domain.
    Type: Grant
    Filed: February 13, 2007
    Date of Patent: November 30, 2010
    Assignee: QUALCOMM Incorporated
    Inventors: Tao Tian, Raghuraman Krishnamoorthi, Krishna Kiran Mukkavilli, Fuyun Ling
  • Patent number: 7728461
    Abstract: Disclosed is an improved noise reducing apparatus using an anti-circuit, including a digital logic circuit and a digital anti-circuit corresponding to the digital logic circuit. The digital anti-circuit functions to cancel noise generated by the digital logic circuit. The anti-circuit includes logic to generate a similar number of switching edges as the logic circuit, where the anti-circuit edges are in the opposite direction as the logic circuit. The anti-circuit may have a circuit structure close to that of the noisy circuit, or can be formed of components different in structure but generating an output pattern similar to (and opposite from) the noisy circuit. In some embodiments, the differently structured components can include a state machine coupled to a memory or look-up-table.
    Type: Grant
    Filed: June 3, 2004
    Date of Patent: June 1, 2010
    Assignee: Cypress Semiconductor Corporation
    Inventor: Paul Beard
  • Publication number: 20100085116
    Abstract: There is provided an FM demodulator comprising a transistor (Q323), a filter unit for producing first and second amplitude-modulated signals from a received frequency-modulated signal, wherein the filter unit is coupled to the switching transistor (Q323), and first and second diodes (D300) connected in opposite relationship for rectifying the first and second amplitude-modulated signals of the filter unit. The filter unit has an LC network and is so dimensioned that there is a linear relationship between the output voltage and the input frequency. The demodulator further has an operating point adjusting unit for adjusting an operating point of the transistor. The operating point adjusting unit (100) is adapted to effect operating point adjustment with a noise negative feedback.
    Type: Application
    Filed: September 11, 2009
    Publication date: April 8, 2010
    Applicant: Sennheiser electronic GmbH & Co. KG
    Inventor: Frank Hagemeyer
  • Patent number: 7683705
    Abstract: A circuit arrangement for matching a demodulator to operating conditions comprises a demodulator designed to demodulate an analog input signal to a demodulated signal. The demodulator is also designed to be driven by a control signal. The circuit arrangement further comprises a sensor which is designed to provide a sensor status signal, and a control unit to whose input side the sensor status signal is applied and which is designed to provide the control signal for the demodulator during operation.
    Type: Grant
    Filed: May 29, 2007
    Date of Patent: March 23, 2010
    Assignee: Infineon Technologies AG
    Inventor: Helmut Koroschetz
  • Patent number: 7653152
    Abstract: Apparatus and methods for data demodulation in FM-FSK communication systems may include comparing the power spectral density (PSD) of the received frequency spectrum with that of the previously received samples using digital signal processing on a multi-sample message. A narrow band FM-FSK receiver may include a filter configured to pass FM signal components of a predetermined signal band, a memory configured to store the filtered signal component, and a DSP operably connected to the filter and the memory. The DSP may be configured to output a digital signal based upon a comparison of successive DSP calculated frequencies associated with a peak power of a power spectrum density (PSD) of successive samples of the filtered multi-sample message.
    Type: Grant
    Filed: July 25, 2006
    Date of Patent: January 26, 2010
    Inventor: Abdullah A. Al-Eidan
  • Patent number: 7542531
    Abstract: A method and system of canceling radio frequency interference (RFI) sourced from a narrow-band radio frequency transmitter to interfere with the operation of a multi-carrier modulation system. The spectral components of the RFI can be represented as a Taylor series of 1/(m-½) where m is an integer and (m-½) is a normalized approximate distance between the frequency of interest and the center frequency of the RFI. The coefficients of the Taylor series are obtained by solving a set of linear equations using the Fourier output at several properly chosen frequencies where the REI components dominate. The coefficients for the Taylor series are formulated as linear combinations of the FFT output at the chosen frequencies and are computed and stored beforehand. Simple multiplications and additions are needed for obtaining the Taylor series coefficients from the FFT output at the chosen frequencies.
    Type: Grant
    Filed: August 4, 2005
    Date of Patent: June 2, 2009
    Assignee: Realtek Semiconductor Corp.
    Inventors: Chia-Liang Lin, Pei-Chieh Hsiao
  • Patent number: 7480348
    Abstract: In an I/Q demodulation circuit, an offset amount determined in an offset detection mode is previously stored so that, in a normal reception mode, an offset is corrected for based on the data thus stored. With this configuration, a DC offset and a phase offset can be corrected for without a delay in an I/Q demodulation operation.
    Type: Grant
    Filed: August 17, 2004
    Date of Patent: January 20, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Yoshiaki Nakano
  • Patent number: 7428280
    Abstract: The present invention has a N pieces of receiving antennas, a propagation path characterization estimator, a weight generator for interference canceller, an array processing interference canceller, a weight generator for signal estimator, a signal estimator, a transmission signal classification apparatus, and a decoding order decision apparatus. The antenna inference elimination circuit eliminates only signal component relating to transmission signal component which does not belong to groups. The signal estimator performs separation and decoding of the transmission signal belonging to the group. The transmission signal classification apparatus classifies the transmission signals from sets of the transmission antennas in which a cross-correlation value of the vector is larger than a threshold value, into one group, and classifies the transmission signal in which the cross-correlation value is smaller than the threshold value, into another group.
    Type: Grant
    Filed: June 21, 2007
    Date of Patent: September 23, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tsuguhide Aoki, Shuichi Obayashi
  • Patent number: 7420409
    Abstract: The invention relates to a demodulator to demodulate frequency-modulated signals FM including a phase locked loop PLL including at least a phase detector, a loop filter and a voltage controlled oscillator function VCO?, characterized in that said voltage controlled oscillator function VCO? has modifiable gain. The invention allows to eliminate drawbacks presented by the conventional use of a complex gain modifiable amplifier at the input of demodulated signal processing means. Application: demodulation of modulated signals: wireless phone, home network.
    Type: Grant
    Filed: October 9, 2003
    Date of Patent: September 2, 2008
    Assignee: DSP Group Switzerland AG
    Inventors: Eric Desbonnets, Frédéric Parillaud, Erick Giroux
  • Patent number: 7421043
    Abstract: An apparatus comprising a first circuit, a second circuit, a third circuit and a fourth circuit. The first circuit may be configured to generate a demodulated signal in response to (i) a modulated signal and (ii) a seed value. The second circuit may be configured to generate a first control signal in response to the demodulated signal. The third circuit may be configured to generate a second control signal in response to (i) the first control signal and (ii) a compensation signal. The fourth circuit may be configured to generate the seed value in response to the second control signal.
    Type: Grant
    Filed: November 27, 2002
    Date of Patent: September 2, 2008
    Assignee: LSI Corporation
    Inventor: Dean L. Raby
  • Patent number: 7330068
    Abstract: Demodulation apparatus includes a transversal filter characterized by coefficients adjusted by a coefficient determiner responsive to a constant modulus error signal and variable mode error signal related to the output of a spectral mean frequency detector having its input coupled to the output of the transversal filter.
    Type: Grant
    Filed: April 16, 2002
    Date of Patent: February 12, 2008
    Assignee: Bose Corporation
    Inventor: Tobe Barksdale
  • Patent number: 7277688
    Abstract: A wireless receiver includes a local oscillator, a mixer, a band pass filter, a DC offset determination module, a DC offset correction module, a subtraction module, and a down converter. The local oscillator produces a local oscillation that a mixer uses to down convert the RF information signal to produce a Very Low Intermediate Frequency (VLIF) information signal at a VLIF and having a DC offset. The band pass filter band pass filters the VLIF information signal. The DC offset determination module produces a DC offset indication for the VLIF information signal. The DC offset correction module generates a DC offset correction based upon the DC offset indication. The subtraction module subtracts the DC offset correction from the VLIF information signal to substantially remove a DC offset of the post-filtered VLIF information signal. The down converter down converts the VLIF information signal to a baseband information signal.
    Type: Grant
    Filed: March 29, 2004
    Date of Patent: October 2, 2007
    Assignee: Broadcom Corporation
    Inventors: Baoguo Yang, Nelson R. Sollenberger
  • Patent number: 7260163
    Abstract: A noise blanker (40, 106) monitors and removes noise from a sampled signal by adaptive filtering (98, 150) the sampled signal to generate trained adaptive filter prediction coefficients. The sampled signal is provided as an output signal when the noise blanker is in a training mode. A noise monitor (34, 154) detects whether noise contained within the sampled signal exceeds a predetermined threshold and provides a control signal in response to the detecting. The noise blanker is placed in a prediction mode for a predetermined amount of time in response to asserting the control signal. A prediction output signal is generated using a plurality of prediction coefficients as an all-pole filter. The prediction output signal has minimal noise content.
    Type: Grant
    Filed: August 9, 2002
    Date of Patent: August 21, 2007
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Junsong Li, Ronald Wang, Raghu G. Raj
  • Patent number: 7133476
    Abstract: Information is recovered from a composite signal including first and second component signals modulated according to respective first and second modulations, for example, 8-PSK and GMSK. The composite signal is processed based on predetermined characteristics of the first and second modulations, for example, signal rotations, to generate a channel model for the first component signal and a whitening filter for the second component signal. The composite signal is filtered according to the whitening filter to generate a filtered signal. A symbol hypothesis for a symbol of the first component signal is evaluated using a metric with respect to the filtered signal that is a function of the whitening filter and the channel model, for example, in a multidimensional Viterbi symbol estimation algorithm. The invention may be embodied as methods, apparatus and computer program products.
    Type: Grant
    Filed: August 1, 2002
    Date of Patent: November 7, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Huseyin Arslan, Rajaram Ramesh
  • Patent number: 7116734
    Abstract: A method for providing maximum likelihood detection with decision feedback interference cancellation is provided. The method includes estimating a current symbol with previous symbol interference (PSI) removed based on estimated previous symbols. A next symbol is estimated with PSI removed based on the estimated current symbol and/or the estimated previous symbols. The current symbol is re-estimated with PSI removed based on the estimated previous symbols and next symbol interference (NSI) removed based on the estimated next symbol. This method of providing maximum likelihood detection with decision feedback interference cancellation may be used in direct sequence spread spectrum systems with relatively short block spreading, such as IEEE802.11b Wireless LAN standard, or in any other suitable systems.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: October 3, 2006
    Assignee: National Semiconductor Corporation
    Inventor: Aydin Nergis
  • Patent number: 7099647
    Abstract: A single chip direct conversion transceiver that includes a substrate on which a mixer unit and a local oscillator are provided as a circuit, and a positive hole formed between the mixer unit and the local oscillator and filled with a conductive plug to block signal leakage. A shield ground surface is formed above the substrate and blocks signal leakage occurring when the signals received through the antenna are input into the mixer and signal leakage occurring when the reference signal is input into the mixer from the local oscillator. A first interconnection is formed above the shield ground surface and connects the mixer unit and the local oscillator. Dielectric layers are formed between the substrate and the shield ground surface and on the shield ground surface to cover the first interconnection.
    Type: Grant
    Filed: January 29, 2004
    Date of Patent: August 29, 2006
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sang-hyun Woo, Jong-ae Park
  • Patent number: 7095799
    Abstract: Systems and methods for providing baseband predistortion within a transmitter. In a simplified embodiment, the transmitter contains a main signal path that receives an input signal and generates a main signal in response thereto. A filter in the main signal path is used for removing unwanted signal components from the main signal. A power amplifier having non-linearity is also located within the transmitter. A digital predistortion module is used by the transmitter to digitally process the input signal to generate a predistortion signal that models an inverse of the non-linearity of the power amplifier. In addition, means, located between the filter and the power amplifier, for combining the predistortion signal with the main signal to generate a combined signal, and for providing the combined signal to the power amplifier, is located within the transmitter.
    Type: Grant
    Filed: April 29, 2002
    Date of Patent: August 22, 2006
    Assignee: Agilent Technologies, Inc.
    Inventor: Richard Neil Braithwaite
  • Patent number: 7024608
    Abstract: Ideal nonlinear distortion compensation is realized by removing an imperfection of amplitude delay characteristic and an affection of inherent deviation that an amplifier has. A linear distortion compensation factor calculating part (18) estimates, based on quadrature demodulated signals (I?ch, Q?ch), the linear distortion characteristic occurring mainly due to imperfection of analog circuits, such as a quadrature modulator (13) and a high-power amplifier (14), and calculates and outputs a linear distortion compensation factor for compensating the linear distortion. A linear distortion compensating part (12) performs a pre-distortion (addition of a reverse characteristic of the linear distortion characteristic) by multiplying the baseband signals (Ich, Qch) by the data of the linear distortion compensation factor.
    Type: Grant
    Filed: February 19, 2003
    Date of Patent: April 4, 2006
    Assignee: NEC Corporation
    Inventor: Yuzo Kurokami