Patents Examined by Khanh Cong Tran
  • Patent number: 6504863
    Abstract: A transceiver includes a receiver and a transmitter. The receiver includes an analog-to-digital conversion device for converting a received analog signal to digital form, and the transmitter includes a digital-to-analog conversion device for converting a digital signal into analog form for transmission. A selector selects the resolutions of the conversion devices. The resolution of the analog-to-digital conversion device is selected based on a received signal quality, e.g., the signal-to-noise ratio or the signal-to interference ratio. The resolution of the digital-to-analog conversion device is selected based on a crest factor of the transmitted signal, the crest factor depending, e.g., on the modulation format of the signal being transmitted. The higher the crest factor, the higher the resolution selected.
    Type: Grant
    Filed: September 7, 1999
    Date of Patent: January 7, 2003
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventor: L. Martin Hellmark
  • Patent number: 6501789
    Abstract: Disclosed herein is a receiving apparatus in a CDMA communication system for transmitting a transmit data subjected to a spread modulation processing with a predetermined spreading factor, and demodulating the transmit data by subjecting received signals to a despread processing. A first despread signal generator multiplies a received signal by the same code as a spreading code on the transmission side for each chip, divides the results of multiplications for all the chips into a plurality of groups, and sums the results of multiplications in each group so as to output respectively a despread signal having a spreading factor which is smaller than the spreading factor on the transmission side. A second despread signal generator sums respective k pair of the despread signals which are output from the first despread signal generator so as to generate a plurality of despread signals having a predetermined spreading factor.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: December 31, 2002
    Assignee: Fujitsu Limited
    Inventors: Tetsuya Yano, Kazuhisa Obuchi
  • Patent number: 6498806
    Abstract: Multi-drop Asymmetrical Digital Subscriber Loop (ADSL) modems have at least two sets of digital front end circuitry which allow for simultaneous connections to at least two local loops. A shared DSL modem is operably associated with each of the two sets of digital front end circuitry and transmits and receives data to and from the digital front end circuitry. A digital interface is operably associated with the shared DSL modem and is configured to communicate with an external network.
    Type: Grant
    Filed: August 17, 1998
    Date of Patent: December 24, 2002
    Assignee: International Business Machines Corporation
    Inventor: Gordon Taylor Davis
  • Patent number: 6487252
    Abstract: An orthogonal frequency division multiplexed wideband communication system provides improved time and frequency synchronization by inserting an unevenly spaced pilot sequence within the constellation data. A receive correlates the received data using the unevenly spaced pilot sequence. The pilot sequence is generated with a maximum length pseudo random noise code and inserted into frequency bins having prime numbers.
    Type: Grant
    Filed: January 29, 1999
    Date of Patent: November 26, 2002
    Assignee: Motorola, Inc.
    Inventors: John Eric Kleider, Michael Eugene Humphrey, Jeffery Scott Chuprun, Chad Scott Bergstrom, Byron L. Tarver
  • Patent number: 6487239
    Abstract: A method and an apparatus for performing message communication accurately at high rate even when the communication line is busy. When the communication line between the message transmitting side and the message receiving side connected with an ISDN network is busy, the call between the message transmitting side and the message receiving side is temporarily interrupted and then a message is transmitted automatically from the message transmitting side to the message receiving side by using call setting information where a transmission message is set in a subaddress.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: November 26, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroyuki Goto, Masato Michinaka, Hirofumi Shimizu
  • Patent number: 6483886
    Abstract: A phase-locked loop circuit (“PLL”) is adjustable in both phase and frequency. By providing a plurality of taps on the voltage-controlled oscillator of the PLL, and providing separate multiplexers, each of which can select a different tap—one for the PLL feedback loop and one for the PLL output—one allows the user to adjust the phase of the output relative to that of the input. Similarly, by providing loadable pre-scale (divide by N), post-scale (divide by K) and feedback-scale (divide by M) counters, one allows the user to adjust the frequency of the output to be M/(NK) times that of the input.
    Type: Grant
    Filed: August 4, 1999
    Date of Patent: November 19, 2002
    Assignee: Altera Corporation
    Inventors: Chiakang Sung, Joseph Huang, Bonnie I. Wang, Richard G. Cliff
  • Patent number: 6480526
    Abstract: This invention is a spread spectrum receive apparatus comprising a plurality of receive branches, wherein each of the plurality of receive branches includes at least one antenna which receives a plurality of different polarized components, and a RAKE receiver, commonly prepared for the plurality of receive branches, for modulating the plurality of different polarized components received, and outputting a modulated signal based on the plurality of different polarized components modulated.
    Type: Grant
    Filed: March 2, 1999
    Date of Patent: November 12, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroki Shoki, Yasuo Suzuki
  • Patent number: 6480524
    Abstract: Sectorisation has been used in cellular communications networks in order to increase capacity without the need for obtaining new cell sites. However, previously, the increase in the number of main antenna beams provided by a base station transceiver has not produced a commensurate increase in capacity. For example, a hex sectored tricellular network is found to provide an increase in capacity by a factor of only 1.6 over a tri sectored tricellular network despite the fact that twice as many antenna beams are provided. A multiple beam antenna arrangement is described where the increase in capacity is commensurate with the increase in the number of antenna beams provided. In one example, a nine sectored tricellular CMDA network is described which comprises a multiple beam antenna arrangement with six antenna elements each provided as columns. The antenna beams may be orthogonal and a 6×6 Butler matrix beamformer is used which is advantageously loss less.
    Type: Grant
    Filed: September 13, 1999
    Date of Patent: November 12, 2002
    Assignee: Nortel Networks Limited
    Inventors: Martin Stevens Smith, Mark Newton, James E Dalley
  • Patent number: 6480531
    Abstract: A method and apparatus for use in a digital system having a plurality of modem devices from receiving de-multiplexed digital channels of information through a transmission link and providing data for use by computer equipment for detecting the presence of defective modem devices, the plurality of modem devices being organized into groups having a predetermined number of modem devices, testing each of the modems in each group against the remainder of the modems in that group, determining the number of tests that each of the modems within the group have passed successfully, selecting among the modems within each group, a ‘leader’ modem having the highest number of pass rate and thereafter testing the remainder of the modems in that group against the chosen ‘leader’ modem thereby reliably isolating defective modems from use during normal operation of the digital system.
    Type: Grant
    Filed: October 23, 1998
    Date of Patent: November 12, 2002
    Assignee: Cisco Technology, Inc.
    Inventor: Pankaj Malhotra
  • Patent number: 6477196
    Abstract: A method of excising one or more narrow-band interfering signals in a direct sequence spread spectrum receiver that performs a magnitude spectral analysis on baseband signals in a detection channel to determine which frequency bins in the spectral analysis output contain the interfering narrow-band signals by comparing the magnitude of the signals in the frequency bins to a threshold. The corrupted frequency bins are determined by the signal magnitudes exceeding the threshold and band reject filters excise the narrow-band signals in the signal channel in accordance with the corrupted frequency bins.
    Type: Grant
    Filed: August 30, 1999
    Date of Patent: November 5, 2002
    Assignee: Rockwell Collins, Inc.
    Inventors: Christopher J. Swanke, Steven L. White
  • Patent number: 6477206
    Abstract: A system for sending and receiving information is capable of sending and receiving a large amount of data. A CPU of a portable computer has an identification code comparator for comparing an identification code preset by a video game machine with an identification code added to a received data string, and a readout controller having a selective reception function to selectively receive the data string depending on a compared result from the identification code comparator.
    Type: Grant
    Filed: July 30, 1999
    Date of Patent: November 5, 2002
    Assignee: Sony Computer Entertainment Inc.
    Inventor: Masayuki Chatani
  • Patent number: 6473455
    Abstract: A method compensates a phase delay of a clock signal used in a data communications system. First, a plurality of delayed clock signals are provided by modifying the amount of delay of the clock signal. In synchronization with one of the delayed clock signals, one or more test data signals and their address signals are sequentially issued and sent to a storage device. In synchronization with the original clock signal, each test data signal is stored in an area that its address signal indicates and then, upon receipt of the address signal at a predetermined time of the original clock signal, a data signal which corresponds to the address signal is read and sent to a controller. At a predetermined time of the delayed clock signal, a data signal is received from the storage device and it is checked whether or not each test data signal and the received data signal are the same.
    Type: Grant
    Filed: October 22, 1999
    Date of Patent: October 29, 2002
    Assignee: Daewoo Electronics Co., Ltd.
    Inventor: Ki Paek Kwon
  • Patent number: 6470053
    Abstract: Methods and arrangements are provided for allowing various devices to communicate data over standard twisted pair wire within a confined region, such as a home environment. The methods and arrangements employ radio frequency (RF) communication techniques to modulate and transmit data signals over existing twisted pair phone lines at RF frequencies. The RF transmitted data can be detected over limited distances by other similarly configured devices. The RF transmitted data is then received and demodulated to regenerate the original data. The methods and arrangements also allow the data transmission to be conducted in accordance with conventional CSMA/CD techniques/protocols. Thus, for example, Ethernet network configured devices can be seamlessly interconnected using the methods and arrangements of the present invention without requiring that additional and/or upgraded wiring be installed in the home environment.
    Type: Grant
    Filed: October 30, 1998
    Date of Patent: October 22, 2002
    Assignee: Compaq Information Technologies Group, L.P.
    Inventor: Ce Richard Liu
  • Patent number: 6470055
    Abstract: Spectral efficient transmitters-receivers (transceivers), modulation-demodulation (Modem) methods, architectures, structures and implementation technologies for enhanced performance and increased capacity CDMA, TDMA, GSM,OFDM, CMA, FDM and other wireless and wired communications, broadcasting and telemetry systems and integrated Modems/Transceivers suitable for operation over Non-Linearly Amplified (NLA) power efficient RF systems are described. Cross-correlated cascaded Time Constrained Signal (TCS) response processors and Long Response (LR) filtered Bit Rate Agile (BRA) in phase (I) and quadrature phase (Q) baseband signals are disclosed. These spectral efficient high performance processing, transmitting and receiving methods are designated as Feher's Quadrature Phase Shift Keying (FQPSK) Transceivers.
    Type: Grant
    Filed: August 9, 1999
    Date of Patent: October 22, 2002
    Inventor: Kamilo Feher
  • Patent number: 6466627
    Abstract: A pulse signal transmitting circuit generates a pulse signal having an enhanced high-frequency component with a reduced power loss. A pulse signal is transmitted to a load circuit through a transmission cable connected to a secondary winding of a transformer. First and second transistors are connected to a primary winding of the transformer. A voltage output from an external power source is input to the primary winding of the transformer when at least one of the first and second transistors is conductive so that a pulse voltage signal is input to the transformer. A booster power supply circuit is located between the external power source and a middle point of the primary winding of the transformer. The booster power supply circuit superimposes a boost voltage onto the voltage input to the primary winding of the transformer so that a high-frequency component of the pulse voltage signal input to the primary winding of the transformer is enhanced.
    Type: Grant
    Filed: February 5, 1999
    Date of Patent: October 15, 2002
    Assignee: Fujitsu Limited
    Inventor: Isamu Kuwana
  • Patent number: 6463092
    Abstract: The system preferably includes a unique transmitter that sends both clock and data signals over the same transmission line. The receiver uses the same transmission line to send data signals back to the transmitter. The transmitter comprises a clock generator, a decoder and a line interface. The clock generator produces a clock signal that includes a variable position falling edge. The falling edge position is decoded by the receiver to extract data from the clock signal. The receiver comprises a clock re-generator, a data decoder and a return channel encoder. The clock re-generator monitors the transmission line, receives signals, filters them and generates a clock signal at the receiver from the signal on the transmission line. The return channel encoder generates signals and asserts them on the transmission line. The signal is asserted or superimposed over the clock & data signal provided by the transmitter.
    Type: Grant
    Filed: September 9, 1999
    Date of Patent: October 8, 2002
    Assignee: Silicon Image, Inc.
    Inventors: Gyudong Kim, Min-Kyu Kim, Seung Ho Hwang
  • Patent number: 6456645
    Abstract: In a digital wireless audio transmission system, a transmitter section includes a local oscillator and frequency modulator to modulate the local oscillator signal with a periodic transmitter spreading signal in order to generate a frequency-modulated radio-frequency signal. An amplitude modulator amplitude-modulates this signal with serial digital data that is generated by an audio interface and a channel encoder. This amplitude-keyed signal which is spread in frequency is then transmitted via a transmit antenna as electromagnetic waves. A receiver section receives these electromagnetic waves via multiple antennae and amplitude-modulates the signal of at least one antenna with antenna modulator signals that have the same frequency as the transmitter spreading signal and a fixed relative phase deviation. All of these antenna signals are then added, and the sum signal is amplified and detected by a small-signal detector.
    Type: Grant
    Filed: October 29, 1999
    Date of Patent: September 24, 2002
    Inventor: Jens Kurrat
  • Patent number: 6445745
    Abstract: A method for phase encoding DPSK and N-PSK which maintains phase continuity and which does not require any reference symbols when using N-PSK. A sequence of known DPSK phases are encoded with respect to an initial phase. The N-PSK phases are then all offset by this same initial phase. The known DPSK phases can be used at a receiver to determine a sum consisting of the initial phase and any further phase shift introduced by the channel, and this sum is used to decode the unknown N-PSK phases. The method is more generally applicable to any case where a switch between a phase encoding method which requires an absolute phase reference and a phase encoding method which does not have an absolute phase reference is to be implemented on a single carrier or channel.
    Type: Grant
    Filed: May 6, 1999
    Date of Patent: September 3, 2002
    Assignee: Nortel Networks Limited
    Inventors: Chandra S. Bontu, Yonghai Gu, Shavantha Kularatna, Peter Barany
  • Patent number: 6445746
    Abstract: A system and method for demodulating slots having a mixed slot formation including differential and coherently encoded slots is disclosed. The method includes pre-phase encoding data and a predetermined sequence in a slot at a transmitter such that the encoded data and the predetermined sequence have equal reference phases from a reference symbol of a previous slot having a reference phase. Another method includes pre-phase encoding the predetermined sequence with a phase determined from a reference symbol from the previous slot at the transmitter. Yet another method includes differentially phase encoding the predetermined sequence according to IS-136A standards using a reference phase of π 4 . In another method pre-phase encoding data includes phase shifting data using one of a group of different phase angles, each of the different phase angles an integer multiple of π 2 .
    Type: Grant
    Filed: August 11, 1999
    Date of Patent: September 3, 2002
    Assignee: Hughes Electronics Corporation
    Inventors: In-Kyung Kim, Wonjin Sung
  • Patent number: 6445757
    Abstract: The invention relates to a diversity combining method and to a receiver. In diversity combining, outputs (33) of a matched filter (25) of each branch are weighted with a quality estimate (32) which is generated in quality means (28b) in such a matter that the quality estimate (30) is proportional to the inverse of the interference strength (31) of the signal. The strength (31) of signal interference is generated in interference means (28c) e.g. in variance-like fashion from the differences between a reference signal (30) generated in reference signal means (28a) as the convolution of the estimated channel impulse response and the predetermined sequence and a signal received from the channel.
    Type: Grant
    Filed: June 3, 1999
    Date of Patent: September 3, 2002
    Assignee: Nokia Telecommunications Oy
    Inventors: Mika Raitola, Harri Jokinen, Pekka Ranta