Patents Examined by Stephen Chin
  • Patent number: 8855255
    Abstract: Systems and methods are provided for performing the required phase calculation in a telecommunications system in order to optimize system performance more quickly and with reduced complexity as compared to prior approaches to solving this problem. In accordance with the preferred exemplary embodiment of the present invention, the phase delay of the precursor equalizer (EQ) is calculated off-line and as a result it is not necessary to fill the precursor EQ delay line with the indicated number of symbols as in the previous approach. Additionally, because the precursor EQ is fractionally spaced, both sine and cosine values of the 4kHz tone's initial phase can be achieved simultaneously. As a result, only 36 quick timing sequence (QTS) symbols are needed in order to perform the required estimation.
    Type: Grant
    Filed: March 29, 2002
    Date of Patent: October 7, 2014
    Assignee: U.S. Robotics Corp.
    Inventors: Qing Chen, Qian Cheng
  • Patent number: 7428270
    Abstract: Disclosed is a unique system and method for recognizing the type of modulation embedded in an unknown complex baseband signal, comprising a receiver section for extracting the complex baseband signal from a modulated signal having a carrier frequency, and comprising an orderly series of signal processing functions for (a) estimating the bandwidth of the unknown signal, (b) removing the out-of-band noise and correcting gross carrier frequency errors, (c) discriminating between constant envelope and irregular envelope signals, (d) estimating and correcting residual carrier frequency errors, (e) classifying a constant envelope signal into one of the following modulation formats: {Continuous Wave (CW), Frequency Modulation (FM), Frequency Shift Keying (FSK)}, and (f) classifying an irregular envelope signal into one of the following modulation formats: {Amplitude Modulation (AM), Double Sideband Suppressed Carrier (DSB-SC), Binary Shift Keying (BPSK), Quaternary Phase Shift Keying (QPSK), ?/4-shifted QPSK, M-ary
    Type: Grant
    Filed: February 15, 2000
    Date of Patent: September 23, 2008
    Inventors: Christian Dubuc, Daniel Boudreau
  • Patent number: 7409028
    Abstract: A method and system provide a stable reference clock for use in a communication system. A phase-locked loop (PLL) receives an input clock signal with potentially unacceptable levels of jitter and wander. The PLL provides a synchronized output clock with significantly reduced jitter and wander. The PLL nominally uses a digital-to-analog converter (DAC) to control a voltage-controlled oscillator (VCO). Applying a loop filter function to the phase difference between the input clock and the output clock generates control values for the DAC. Loop filter adaptation is based on control value averages, which enhances stability and frequency locking performance. Frequency lock detection is based on the consistency of the DAC control values, rather than on a predetermined target value, making the PLL a self-calibrating system. The long-term average of the control value in the locked state may be stored for later use as an initial DAC setting.
    Type: Grant
    Filed: December 22, 2000
    Date of Patent: August 5, 2008
    Assignee: Ericsson Inc.
    Inventor: Eugene D. Ham, III
  • Patent number: 7379515
    Abstract: A universal frequency translation module (UFT) frequency translates an electromagnetic (EM) input signal by sampling the EM input signal according to a periodic control signal (also called an aliasing signal). By controlling the relative sampling time, the UFT module implements a relative phase shift during frequency translation. In other words, a relative phase shift can be introduced in the output signal by sampling the input signal at one point in time relative to another point in time. As such, the UFT module can be configured as an integrated frequency translator and phase-shifter. This includes the UFT module as an integrated down-converter and phase shifter, and the UFT module as an integrated up-converter and phase shifter. Applications of universal frequency translation and phase shifting include phased array antennas that utilize integrated frequency translation and phase shifting technology to steer the one or more main beams of the phased array antenna.
    Type: Grant
    Filed: March 2, 2001
    Date of Patent: May 27, 2008
    Assignee: ParkerVision, Inc.
    Inventors: Martin R Johnson, Jonathan S Jensen, Robert T Short, Jamison L Young, David F Sorrells, Michael J Bultman, Robert W Cook, Richard C Looke, Charley D Moses, Jr.
  • Patent number: 7224741
    Abstract: A system for allocating subcarriers to subscribers, comprising a subcarriers allocation controller, connected to a subcarrier modulation unit in a transmitter and to a subcarrier demodulation unit in a receiver for setting a group of subcarriers to be used therein. The transmitter and the receiver are part of the transceiver and subcarriers allocation is made according to a Reed-Solomon code. In a multicarrier system, a method for allocating subcarriers to subscribers, comprising the steps of: A. keep a table of R-S codes for frequency group allocation to base stations; B. assign one set of subcarriers based on R-S codes to a base station; C. assign other sets of subcarriers based on R-S codes to other base stations in such a way that adjacent base stations have different R-S codes, to minimize the number of collision points therebetween.
    Type: Grant
    Filed: July 24, 2000
    Date of Patent: May 29, 2007
    Inventor: Zion Hadad
  • Patent number: 7190744
    Abstract: An equalizer comprises: an FIR; a trellis decoder coupled to the FIR; a mapper coupled to the trellis decoder; and a decision feedback equalizer coupled to the mapper. The decision feedback equalizer receives the mapped and scaled output of the trellis decoder as input and an error signal is generated by subtracting an output of the decision feedback equalizer from the input to the trellis decoder.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: March 13, 2007
    Assignee: Micronas Semiconductors, Inc.
    Inventors: Jingsong Xia, Richard W. Citta, Scott M. LoPresto, Wenjun Zhang
  • Patent number: 7187727
    Abstract: To provide a clock and data recovery circuit which facilitates alteration of the frequency range and adjustment of characteristics.
    Type: Grant
    Filed: December 17, 2001
    Date of Patent: March 6, 2007
    Assignee: NEC Electronics Corporation
    Inventor: Takanori Saeki
  • Patent number: 7184486
    Abstract: A method of decoding low-density parity-check codes comprises a first step that includes calculating ??rRml, for each parity check equation, at iteration i?1, in response to a third step. A second step includes decision aided equalizing, at iteration i, in response to the first step. The third step includes calculating ??rQ?m, for each parity check equation, at iteration i in response to the second step, wherein ??rQ?m represents information from bit node l to equation node m, one for each connection, and wherein ??rRml represents information from equation node m to bit node l, one for each connection.
    Type: Grant
    Filed: December 7, 2000
    Date of Patent: February 27, 2007
    Assignee: Marvell International Ltd.
    Inventors: Zining Wu, Gregory Burd
  • Patent number: 7170925
    Abstract: In a CDMA receiver for applying despread processing to direct wave or delayed waves that arrive via each path of multiple paths, applying synchronous detection processing to the despread signals obtained, combining the detection signals of respective paths and discriminating the received data on the basis of the combined signal, (1) a weighting unit provided for every path measures power of delayed received waves that arrive via its own path and, if the reception power is less than a set level (breakpoint level), subjects an output signal to weighting conforming to the reception power; (2) a RAKE combiner combines signals output from the weighting units of the respective paths; and (3) a data discrimination unit discriminates receive data based upon the output signal of the combiner.
    Type: Grant
    Filed: February 13, 2002
    Date of Patent: January 30, 2007
    Assignee: Fujitsu Limited
    Inventors: Noriyuki Kawaguchi, Satoshi Nakamura, Kensuke Sawada, Dai Kimura, Tokuro Kubo, Morihiko Minowa
  • Patent number: 7167502
    Abstract: A communication system transmits orthogonally encoded data at a symbol rate which is selected from a plurality of symbol rates. The data is encoded in a plurality of packets, each packet having a plurality of symbols having signal points in a field. The signal points of consecutively transmitted symbols are correlated unless the rate is changed, and the data is encoded such that only particular orthogonal descendants of a selected maximum rate code are used. The encoded data is transmitted to a receiver, and orthogonally decoded. A change in the rate of data transmission is recognized when the signal points of consecutively transmitted symbols are not correlated.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: January 23, 2007
    Assignee: Skyworks Solutions, Inc.
    Inventor: Lih-Feng Tsaur
  • Patent number: 7167513
    Abstract: An in-phase and guadrature (IQ) imbalance error-correction method includes estimating, on the basis of a constellation error in a received orthogonal frequency division multiplexing (OFDM) signal, an extent of an I/Q imbalance error, caused by direct IQ conversion of the received OFDM signal. On the basis of that extent, an equalizing transformation that reduces that error is estimated.
    Type: Grant
    Filed: December 31, 2001
    Date of Patent: January 23, 2007
    Assignee: Intel Corporation
    Inventors: Ernest T. Tsui, Jian Lin
  • Patent number: 7154935
    Abstract: A method for receiving radio signals in a mobile station, and a mobile station for sending and receiving radio signals are proposed. The method and the mobile station have the aim of correcting predistorted code-spread and phase-modulated radio signals with respect to a phase error. In this context, in the receiver of the mobile station, the phase is determined for the radio signals, in order to carry out a phase demodulation, and the phases are mapped in a preselected phase zone and averaged, in order to formulate therefrom a phase correction factor, by which the code-despread radio signals are multiplied in order to correct the phase error. The method according to the present invention therefore improves the data detection of the received radio signals.
    Type: Grant
    Filed: October 11, 2000
    Date of Patent: December 26, 2006
    Assignee: Robert Bosch GmbH
    Inventors: Frank Kowalewski, Peter Mangold
  • Patent number: 7136438
    Abstract: BB input units input baseband received signals. An initial weight data setting unit sets weighting coefficients to be utilized in the interval of a training signal as initial weighting coefficients. A gap compensating unit compensates control weighting coefficients with a gap error signal and outputs the updated weighting coefficients acquired as a result of the compensation. A weight switching unit selects the initial weighting coefficients in the interval of the training signal and selects the updated weighting coefficients in the interval of the data signal. Then the weight switching unit outputs the selected initial weighting coefficients and updated weighting coefficients as the weighting coefficients. A synthesizing unit weights the baseband received signals with the weighting coefficients and then sums them up.
    Type: Grant
    Filed: March 31, 2005
    Date of Patent: November 14, 2006
    Assignee: Sanyo Electric Co., Ltd.
    Inventor: Yoshiharu Doi
  • Patent number: 7130367
    Abstract: A digital delay lock loop (DLL) circuit for receiving parallel data and clock signals, deserializing the high speed parallel data to low speed data, and for improving setup and hold times. A DLL circuit for an N-bit datapath, includes a clock DLL configured to provide a clock signal pulse within an eye opening of each of N data signals. The DLL circuit further includes N data DLLs, each being configured to adjust a delay of a data signal to substantially center the eye opening of the data signal on the clock signal pulse.
    Type: Grant
    Filed: April 9, 2002
    Date of Patent: October 31, 2006
    Assignee: Applied Micro Circuits Corporation
    Inventors: Wei Fu, Joseph J. Balardeta, James Corona
  • Patent number: 7123652
    Abstract: A digital filtering system for filtering sample data includes a delay network for delaying input sample data to provide multiple delayed sample data outputs. The filtering system also includes a filter network represented by a decomposed coefficient weighting matrix for processing the delayed sample data outputs. A processor produces a filtered output by computing a weighted product summation of the delayed sample data outputs and the coefficient weighting matrix. The decomposed coefficient weighting matrix is derived by factoring a first coefficient weighting matrix with a common row factor and/or sparse matrix or by factoring based on matrix row or column symmetry.
    Type: Grant
    Filed: October 12, 1999
    Date of Patent: October 17, 2006
    Assignee: Thomson Licensing S.A.
    Inventor: David Lowell McNeely
  • Patent number: 7120198
    Abstract: A coherent adaptive subcarrier modulation system applies subcarrier modulation to quadrature modulated signals with constant envelope modulation suitable for efficient sinewave and squarewave subcarrier modulations. The quadrature subcarrier enables the addition of new signals to the in-phase and quadrature phase signals with spectral isolation in the Global Position System while maintaining a constant envelop amplitude.
    Type: Grant
    Filed: May 26, 1999
    Date of Patent: October 10, 2006
    Assignee: The Aerospace Corporation
    Inventors: Philip A. Dafesh, Tien M. Nguyen
  • Patent number: 7110435
    Abstract: Frequency translation and spread spectrum applications of same are described herein. Such applications include, but are not limited to, unified down-conversion and de-spreading, unified up-conversion and spreading, RAKE receivers utilizing unified down-conversion and de-spreading, and Early/Late receivers utilizing unified down-conversion and de-spreading, and combinations and applications of same. Additionally, applications are included for limiting spectral growth during unified up-conversion and spreading of a baseband signal.
    Type: Grant
    Filed: March 14, 2000
    Date of Patent: September 19, 2006
    Assignee: ParkerVision, Inc.
    Inventors: David F. Sorrells, Michael J. Bultman, Charles D. Clements, Robert W. Cook, Joseph M. Hamilla, Richard C. Looke, Charley D. Moses, Jr., Gregory S. Rawlins, Michael W. Rawlins, Gregory S. Silver
  • Patent number: 7103089
    Abstract: A method of transmitting and receiving a spread spectrum signal, wherein a product of a lower bit rate signal and a second PN-code equals the bit rate of a higher bit rate signal, and wherein a first PN-code sequence is used to spread the product or the higher bit rate signal to a predetermined output chip rate signal which is transmitted. At a receiver, the spread spectrum signal is received and demodulated and in a first operation the demodulated signal is correlated with the first PN-code sequence and in a second operation the output from the first mentioned correlating step is correlated with the second PN-code sequence. The demodulated signal is treated as either a higher bit rate signal or a lower bit rate signal based on the first and second correlations operations.
    Type: Grant
    Filed: December 7, 2000
    Date of Patent: September 5, 2006
    Assignee: Koninklijke Philips Electronics, N.V.
    Inventor: Kenneth R. Whight
  • Patent number: 7099371
    Abstract: The present invention relates to an orthogonal spreading code in a code division multiple access (CDMA) mobile communication system, and more particularly, to a method for generating and allocating code or code pairs on the basis of an orthogonal code set, which is generated using orthogonal spreading codes, so as to reduce a peak-to-average power ratio and enlarge the length of an interference free window. In accordance with the invention, at least one orthogonal code set is generated based upon orthogonal spreading codes, one of the at least one orthogonal code set is determined as a representative orthogonal code set, and then the order is allocated according to rules determined based upon the representative orthogonal code set. The codes or code pairs are generated and allocated using the orthogonal spreading codes, so as to reduce a Peak-to-Average Power Ratio or extend the length of an interference free window (IFW).
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: August 29, 2006
    Assignee: LG Electronics Inc.
    Inventor: Dong Wook Roh
  • Patent number: 7095796
    Abstract: A low power radio transmitter includes an intermediate frequency stage, signal-to-pulse conversion module, and a power amplifier. The intermediate frequency stage up-converts the frequency of a base-band digital signal into an N-bit signal at the intermediate frequency. The signal-to-pulse conversion module converts the N-bit signal at the intermediate frequency into a pulse signal of M-bits at the radio frequency. As such, the signal-to-pulse conversion module is taking an N-bit signal (e.g., an 8-bit digital signal) and converting it into an M-bit pulse signal (e.g., a 1-bit pulse stream). Accordingly, the M-bit signal at the radio frequency is essentially a square-wave, which has a peak to average ratio of zero, is subsequently amplified by the power amplifier.
    Type: Grant
    Filed: January 7, 2002
    Date of Patent: August 22, 2006
    Assignee: VIXS, Inc.
    Inventors: Michael May, Michael Cave, James Girardeau, Mathew Rybicki