Patents Examined by Stephen Chin
  • Hybrid frequency-time domain equalizer
    Patent number: 7042937
    Abstract: A channel decoder employs a hybrid frequency-time domain equalizer for effectively combining a frequency domain equalizer with a time domain equalizer to achieve superior static and dynamic multi-path performance compared to conventional decision feedback equalizers. A frequency domain equalizer structure is included within the forward path of a time domain, decision feedback equalizer, with both the frequency domain and time domain portions employing a common error vector. Updates to the taps (frequency bins) may be adapted individually, or fully within the frequency domain without altering the feedback filter. Improved performance, including performance for noisy channels with deep notches, is achieved, and the frequency domain equalizer portion is relieved from equalizing minimum phase zeros of the channel.
    Type: Grant
    Filed: April 23, 2001
    Date of Patent: May 9, 2006
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: Dagnachew Birru
  • Soft bit computation for a reduced state equalizer
    Patent number: 7042938
    Abstract: Method and apparatus for soft bit computation with a reduced state equalizer. The method assures that the number of states in the equalizer is reduced to obtain acceptable complexity, while also ensuring that soft bit computation is performed for substantially all bits. The method involves computing a first set of soft bits from bits transmitted in a received signal, using a reduced-state trellis with finite non-zero delay, calculating hard decisions in response to the received signal, and also ensuring that substantially all soft bits are computed by employing zero-delay soft decision-making or decision-feedback equalization to compute a second set of soft bits. Furthermore, the hard decisions are used to compute the second set.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: May 9, 2006
    Assignee: Nokia Corporation
    Inventors: Andrei Malkov, Heikki Berg, Pekka Kaasila, Kiran Kumar Kuchi, Jan C. Olivier
  • Adaptive information compression
    Patent number: 7039105
    Abstract: An adaptive information compression system and method conserves information bandwidth or storage space by compressing underutilized information present in a wide-band signal into a much narrower maximum utilized information band signal. This is achieved by obtaining a spectral concentration map of an input wide-band signal by transforming the wide-band signal into the frequency domain and de-selecting the data space where there is substantially little spectral activity. A narrow-band signal is created by reformatting the remaining data space into a contiguous narrow-band signal. The original time-domain image of the data, which has the inactive spectra removed, is reconstructed from the narrow-band signal, thus allowing the total time-domain bandwidth to be significantly less than the original.
    Type: Grant
    Filed: April 17, 2001
    Date of Patent: May 2, 2006
    Assignee: Lockheed Martin Corporation
    Inventors: Arleigh B. Baker, James H. Hughen
  • Method and apparatus for generating a composite signal
    Patent number: 7039122
    Abstract: A programmable waveform generator forms a composite transmission signal containing multiple information signals using a reduced number of hardware components to modulate the phase and amplitude of the carrier signal. A signal generator develops baseband direct sequence spread spectrum digital bit streams from corresponding input data signals. The values of the digital bit steams are used to simultaneously control states of phase modulators and variable attenuators which modulate the phase and amplitude of the in-phase and quadrature carrier components. The programmable waveform generator can be used to implement an interplex modulator producing a constant-envelope composite signal with fewer phase modulators and attenuators.
    Type: Grant
    Filed: October 17, 2001
    Date of Patent: May 2, 2006
    Assignee: ITT Manufacturing Enterprises, Inc.
    Inventor: Philip George Dragonetti
  • Signal demodulation method and apparatus for reproducing data from received signal
    Patent number: 7039123
    Abstract: A demodulation method, and apparatus, for reproducing data from a received signal. The demodulation method includes the steps of: receiving a signal including a series of frames each containing a training signal for automatic equalization processing and a data signal; controlling an amplitude of the received signal by AGC processing so as to make the amplitude a predetermined level; conducting demodulation processing on the signal subjected to the AGC processing; periodically conducting automatic equalization processing so as to adapt the modulated signal to characteristics of the signal transmission path based on each training signal of the frame; and setting values of a time constant of the AGC processing and an update repetition period of the automatic equalization processing so as to satisfy a predetermined relation.
    Type: Grant
    Filed: November 6, 2001
    Date of Patent: May 2, 2006
    Assignee: Hitachi Koksusai Electric, Inc.
    Inventors: Yoshiro Kokuryo, Kunihiko Kondo, Hiroyuki Ando, Nobuo Hirose
  • Method and apparatus for base station and mobile station time calibration
    Patent number: 7039098
    Abstract: A method and apparatus for calibrating a Base Station and Mobile Station for use in systems that use round trip delay and systems that do not use round trip delay.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: May 2, 2006
    Assignee: Qualcomm Incorporated
    Inventor: Saed Younis
  • Reduced complexity correlator for use in a code division multiple access spread spectrum receiver
    Patent number: 7039134
    Abstract: A reduced complexity correlator that enables the re-use of the most complex portions of a correlator, namely the multiplier and adder. The correlator of the present invention is especially well-suited for use in CDMA and W-CDMA spread spectrum communication systems that require the use of numerous correlators in their operation. Multiple input samples, multiple codes and integration results are stored in shift registers and circularly shifted and clocked out at appropriate clock rates such that the multiplication and accumulation steps of the correlation process are synchronized.
    Type: Grant
    Filed: January 22, 2002
    Date of Patent: May 2, 2006
    Assignee: Comsys Communication & Signal Processing Ltd.
    Inventors: Yaniv Avital, Ehud Reshef
  • Phase detector and signal locking system controller
    Patent number: 7039148
    Abstract: A phase detector and signal locking system controller for use in a digital phase-locked loop (PLL) application includes a first and a second phase detector where the first phase detector result is used to control the initial pull-in and the second phase detector is used to control fine tuning once the phase differences are too small for appropriate detection by the first phase detector. A post processing and control unit operates to effectively merge the two phase detector outputs and to apply the appropriate gain factor that can be used to control a PLL system.
    Type: Grant
    Filed: August 2, 2001
    Date of Patent: May 2, 2006
    Assignee: Semtech Corporation
    Inventors: Jonathan Lamb, Wolfgang Bruchner, Richard Lansdowne
  • Adaptive coefficient signal generator for adaptive signal equalizers with fractionally-spaced feedback
    Patent number: 7039104
    Abstract: An adaptive coefficient signal generator for use in an adaptive signal equalizer with fractionally-spaced feedback. The signals representing the feedback tap coefficients are generated in conjunction with a timing interpolation parameter such that the fractionally-spaced feedback circuitry dynamically emulates symbol-spaced feedback circuitry.
    Type: Grant
    Filed: December 17, 2002
    Date of Patent: May 2, 2006
    Assignee: Scintera Networks, Inc.
    Inventors: Abhijit G. Shanbhag, Qian Yu, Abhijit Phanse, Jishnu Bhattacharjee, Debanjan Mukherjee, Fabian Giroud, Venugopal Balasubramonian
  • Arrangement for adaptive baseband filter selection
    Patent number: 7039093
    Abstract: A digital signal detector arrangement comprises at least two selectable baseband filters for receiving a digital signal, a signal estimator receiving the output signal of the selected baseband filter, a modulator unit receiving the estimated signal from the signal estimator, a subtractor for subtracting the modulated signal from the received digital signal, and a determination unit receiving the signal from the subtractor for selecting the baseband filter.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: May 2, 2006
    Assignee: Siemens Communications, Inc.
    Inventors: Antoine J. Rouphael, Benny Vejlgaard, Thomas Klingenbrunn, Lichung Chu
  • Pilot signal cycling technique for a control system that reduces distortion produced by electrical circuits
    Patent number: 7035312
    Abstract: A control system comprising an electrical circuit that produces distortion where the electrical circuit has a frequency band of operation. A pilot modulated carrier signal is frequency hopped about the frequency band of operation. The hopping pilot modulated carrier signal does not interfere with any signal applied to or generated by the electrical circuit as it is not at any time located within the frequency band of operation. Information obtained from the hopping pilot modulated carrier is provided to the control system which uses such information to cancel the distortion produced by the electrical circuit.
    Type: Grant
    Filed: June 21, 2002
    Date of Patent: April 25, 2006
    Assignee: Lucent Technologies Inc.
    Inventor: Robert Evan Myer
  • Doppler corrected communications receiver and method of removing doppler frequency shift
    Patent number: 7035315
    Abstract: A method and communications receiver is disclosed that removes Doppler frequency shift in a spread spectrum communications signal. A pilot channel rake section has I and Q Doppler estimation channels for estimating the Doppler change in frequency based on a common pilot channel. A data channel rake section has I and Q data channels for receiving the Doppler change in frequency from the pilot channel rake section and canceling any Doppler error.
    Type: Grant
    Filed: April 24, 2001
    Date of Patent: April 25, 2006
    Assignee: Lucent Technologies Inc.
    Inventor: Po-An Sung
  • Decision feedback equalizer with dynamic feedback control
    Patent number: 7035330
    Abstract: A decision feedback equalizer with dynamic feedback control for use in an adaptive signal equalizer. Timing within the decision feedback loop is dynamically controlled to optimize recovery of the data signal by the output signal slicer. The dynamic timing is controlled by a signal formed as a combination of feedback and feedforward signals. The feedback signal is an error signal related to a difference between pre-slicer and post-slicer signals. The feedforward signal is formed by differentiating and delaying the incoming data signal.
    Type: Grant
    Filed: January 30, 2004
    Date of Patent: April 25, 2006
    Assignee: Scintera Networks, Inc.
    Inventors: Abhijit G. Shanbhag, Qian Yu, Abhijit M. Phanse, Jishnu Bhatacharjee, Debanjan Mukherjee, Venugopal Balasubramonian, Fabian Giroud, Edem Ibragimov
  • Receiver apparatus
    Patent number: 7035348
    Abstract: A receiver configured to receive a plurality of signals k (k=1, 2, . . . , M) allocated in a first frequency band. The receiver includes a frequency conversion section for reallocating the signals k in a second frequency band for sampling by a single AD converter at a sampling frequency fs such that digital data of the sampled signals k are obtained in a third frequency band extending from zero Hz to a frequency represented by fs/2; and a signal extraction section for extracting a target base band signal k from the digital data obtained by the AD conversion section. The frequency conversion section performs the reallocation in such a manner that at least a frequency represented by Jfs/2 (J is an integer) is located between the frequencies of at least two of the signals k and that the sampled signals do not overlap.
    Type: Grant
    Filed: May 24, 2002
    Date of Patent: April 25, 2006
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Noriyoshi Suzuki, Tomohisa Harada, Tsutayuki Shibata, Hisanori Uda, Hiroaki Hayashi, Nobuo Itoh
  • Process and device for extracting digital data contained in a signal conveyed by an information transmission channel, in particular for a cellular mobile telephone
    Patent number: 7035357
    Abstract: A device includes a receiver including an estimation block for estimating the impulse response of the transmission channel and a transformation block. The transformation block may include a preprocessing block for determining a phase minimum transformed impulse response corresponding to a transformed channel based upon the estimated impulse response of the transmission channel, and a filter for filtering the signal received. This makes it possible to retain equality between the autocorrelation of the signal received and the autocorrelation of the filtered signal. Further, the receiver may include an equalizer for applying an equalization processing operation to the filtered signal while taking account of the transformed impulse response.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: April 25, 2006
    Assignee: STMicroelectronics N.V.
    Inventor: Corinne Bonhomme
  • Phase-noise measurement with compensation for phase noise contributed by spectrum analyzer
    Patent number: 7035324
    Abstract: A method and apparatus compensates for phase noise added by a spectrum analyzer from phase noise measurements of a signal under test (SUT) taken by the spectrum analyzer. The method comprises the steps of measuring the phase noise of the SUT, determining the added phase noise of the spectrum analyzer, and applying a mathematical correction to the measured phase noise. A spectrum analyzer apparatus that compensates for added phase noise comprises a controller portion, a memory portion, a signal conversion and detection portion, and a compensation algorithm stored in the memory portion. A system that compensates for added phase noise comprises a controller having a control algorithm and a spectrum analyzer. The compensation and control algorithms are computer programs that implement the method of the present invention.
    Type: Grant
    Filed: August 1, 2001
    Date of Patent: April 25, 2006
    Assignee: Agilent Technologies, Inc.
    Inventors: Wing Jong Mar, Joseph Michael Gorin
  • Soft slicer in a hybrid decision feedback equalizer
    Patent number: 7035329
    Abstract: A method and apparatus for estimating a transmitted symbol from a received sample as a function of Signal-to-Interference and Noise Ratio (SINR) of the received sample. The received sample is quantized and mapped to a region of a grid overlaid on the transmitted symbol constellation. The region may correspond to a symbol estimate value or may be processed further to obtain a symbol estimate value. The regions in one embodiment are rectangular. The symbol estimate values may be stored in a memory storage unit.
    Type: Grant
    Filed: July 18, 2002
    Date of Patent: April 25, 2006
    Assignee: Qualcomm, Inc.
    Inventors: Srikant Jayaraman, Ivan Jesus Fernandez Corbaton, John E. Smee
  • Parallel concatenated code with soft-in soft-out interactive turbo decoder
    Patent number: 7035342
    Abstract: A method for parallel concatenated (Turbo) encoding and decoding. Turbo encoders receive a sequence of input data tuples and encode them. The input sequence may correspond to a sequence of an original data source, or to an already coded data sequence such as provided by a Reed-Solomon encoder. A turbo encoder generally comprises two or more encoders separated by one or more interleavers. The input data tuples may be interleaved using a modulo scheme in which the interleaving is according to some method (such as block or random interleaving) with the added stipulation that the input tuples may be interleaved only to interleaved positions having the same modulo-N (where N is an integer) as they have in the input data sequence. If all the input tuples are encoded by all encoders then output tuples can be chosen sequentially from the encoders and no tuples will be missed.
    Type: Grant
    Filed: September 12, 2001
    Date of Patent: April 25, 2006
    Assignee: Broadcom Corporation
    Inventors: Kelly B. Cameron, Hau Thien Tran, Ba-Zhong Shen, Christopher R. Jones
  • Efficient method for traceback decoding of trellis (Viterbi) codes
    Patent number: 7035356
    Abstract: Methods and apparatus are provided for efficiently implementing a traceback decoding of Viterbi codes. A Viterbi decoder circuit having at least two data selection blocks and at least two trace registers is described. The number of registers corresponds to the number of states in a Viterbi trellis diagram applicable to encoded data. The trace registers are used to represent the current state best metric and are each configured to send their output to the inputs of the predecessor states representing the possible branches to the current state. The best metric for the predecessor state is determined using a survivor vector stored in memory. Traceback occurs by sequentially reading survivor vectors from memory, using the vectors to control the data selection blocks, and using the trace registers to sequentially identify predecessor states in the traceback.
    Type: Grant
    Filed: October 25, 2001
    Date of Patent: April 25, 2006
    Assignee: Altera Corporation
    Inventor: Martin Langhammer
  • Apparatus and method for decode arbitration in a multi-stream multimedia system
    Patent number: 7035355
    Abstract: An apparatus and method are described for mapping a plurality of multimedia streams (e.g., received from a set of satellite transponders) across a lesser plurality of decoders. In one embodiment, arbitration logic allocates the multimedia streams to divide the decoding load equally among the group of decoders (or at least as equally as possible). Allocation may occur statically, when the system is initialized, or dynamically, as the streams are being processed. In addition, in one embodiment, the arbitration logic monitors the amount of multimedia data for each stream stored in a buffer and causes streams to be serviced by the decoders which have relatively more stored multimedia data.
    Type: Grant
    Filed: October 4, 2001
    Date of Patent: April 25, 2006
    Assignee: Digeo, Inc.
    Inventors: Eric Lais, Mark Greenberg, Manish Shah