Patents Examined by Dung X. Nguyen
  • Patent number: 6952462
    Abstract: A phase detector generates a phase dependent control signal according to the phase relationship between a first and second clock signal. The phase detector includes first and second phase detector circuits receiving the first and second clock signals and generating select signals having duty cycles corresponding to the phase relationship between the clock edges of the first and second clock signals. The phase detector also includes a charge pump that receives select signals from the phase detector circuits and produces an increasing or decreasing control signal when the first and second clock signals do not have the predetermined phase relationship, and a non-varying control signal when the first and second clock signals do have the predetermined phase relationship. The control signal may be used to adjust the delay value of a voltage-controlled delay circuit in order to adjust the phase relationship between the first and second clock signals to have a predetermined phase relationship.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: October 4, 2005
    Assignee: Micron Technology, Inc.
    Inventor: Ronnie M. Harrison
  • Patent number: 6940935
    Abstract: Local source data is first sampled at an original sampling rate and then resampled at a first resampling rate which is equal to the framing rate for transmitting said data to the remote source. The resampled local source data is then delayed by the transmission time between the local and remote data sources. The data from the remote relay which is resampled at the remote source at the first resampling rate and the delayed resampled data at the local source are both then resampled at a second resampling rate, at an original sampling rate, to produce aligned data at the local source.
    Type: Grant
    Filed: April 5, 2001
    Date of Patent: September 6, 2005
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Tony J. Lee, Jeffrey L. Hawbaker
  • Patent number: 6934326
    Abstract: A communication apparatus that is selectively connectable to a communication device. A communicator executes a first communication mode to transmit a first predetermined signal to a communication device that designates a specific mode, and the communication device responds by issuing a second predetermined signal. The communicator executes a second communication mode to transmit a third predetermined signal to the communication device that requests a transmission of the first predetermined signal from the communication device, and upon receipt of the first predetermined signal from the communication device, transmits the second predetermined signal to the communication device. A controller controls the execution of either the first communication mode or the second communication mode upon initializing a communication with the communication device.
    Type: Grant
    Filed: June 21, 2002
    Date of Patent: August 23, 2005
    Assignee: Panasonic Communications Co., Ltd
    Inventor: Stephen Palm
  • Patent number: 6931086
    Abstract: A phase detector generates a phase dependent control signal according to the phase relationship between a first and second clock signal. The phase detector includes first and second phase detector circuits receiving the first and second clock signals and generating select signals having duty cycles corresponding to the phase relationship between the clock edges of the first and second clock signals. The phase detector also includes a charge pump that receives select signals from the phase detector circuits and produces an increasing or decreasing control signal when the first and second clock signals do not have the predetermined phase relationship, and a non-varying control signal when the first and second clock signals do have the predetermined phase relationship. The control signal may be used to adjust the delay value of a voltage-controlled delay circuit in order to adjust the phase relationship between the first and second clock signals to have a predetermined phase relationship.
    Type: Grant
    Filed: June 20, 2002
    Date of Patent: August 16, 2005
    Assignee: Micron Technology, Inc.
    Inventor: Ronnie M. Harrison
  • Patent number: 6928121
    Abstract: A constrained-envelope digital communications transmitter (10) places constraints on the envelope of spectrally constrained, digitally modulated communication signals (46) converted into diverse frequency channels (54) and combined into a composite signal (58). The envelope constraints achieve lower peak-to-average power ratio without allowing significant spectral regrowth. The composite signal (58) is applied to a plurality of cascade-coupled constrained-envelope generators (64). Each constrained-envelope generator (64) detects overpeak events (66) and configures corrective impulses (68) for the overpeak events (66). The corrective impulses (68) are distributed to the respective frequency channels (54) in accordance with a predetermined distribution profile (102) and are filtered into allocated shaped pulses (120) that exhibit a constrained spectrum.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: August 9, 2005
    Assignee: Intersil Americas, Inc.
    Inventors: Daniel D. MacFarlane Shearer, III, James A. Sills
  • Patent number: 6925127
    Abstract: A receiver decodes quantized and unquantized wanted data symbols from received signal samples. The receiver comprises a control adapted to process a group of currently received signal samples to determine a corresponding current set of unquantized wanted data symbols and an interfering waveform representative of a sum of other unwanted data symbols by subtracting an amount of a previously decoded set of quantized wanted symbols and a previously determined interfering waveform. A quantizer quantizes the determined current set of unquantized wanted symbols to obtain corresponding quantized symbols.
    Type: Grant
    Filed: October 6, 2000
    Date of Patent: August 2, 2005
    Assignee: Ericsson Inc.
    Inventor: Paul W. Dent
  • Patent number: 6920189
    Abstract: The present invention relates to a carrier recovery means in particular in a channel decoding unit or a digital demodulating unit of a digital broadcasting receiver. The inventive carrier recovery means comprises at least first and second phase error detecting means (2, 4) in which the first phase error detecting means (2) generates a robust phase error signal based on a digital input signal. Said second phase error detecting means (4) receives said robust phase error signal and generates therefrom a frequency sensitive phase error signal which is representative for the frequency error or frequency offset between the frequency of the receiver and the frequency of the carrier of the received digital input signal. The frequency sensitive phase error signal is then used to reduce at least the frequency error with respect to the received digital input signal to enable locking of the receiver to the carrier of the digital signal.
    Type: Grant
    Filed: June 23, 2000
    Date of Patent: July 19, 2005
    Assignee: Sony International (Europe) GmbH
    Inventor: Gerd Spalink
  • Patent number: 6914932
    Abstract: Received level measurement circuit 1071 performs received level measurement using input despread traffic channel data. Received level measurement circuit 1072 performs received level measurement using input despread common control channel data. These received levels are respectively output from received level measurement circuits 1071 and 1072 to correlation circuit 1075. Correlation circuit 175 first performs correlation calculation between paths in respective profiles of the traffic channel and common control channel each generated based on respective received level. Based on the result of the correlation calculation, path selection is performed to determine a reception timing.
    Type: Grant
    Filed: June 27, 2000
    Date of Patent: July 5, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kazuyuki Miya, Satoshi Imaizumi
  • Patent number: 6907095
    Abstract: A clock ride-over circuit in which clock ride-over may be achieved even if jitter is contained in clocks prior to and subsequent to ride-over and no control input signal for write and readout is applied from outside. A clock prior to rideover CLK—1 is detected by a clock subsequent to ride-over CLK—2 which is of a higher speed than the clock prior to ride-over. A timing signal TIM of a constant period, generated by a counter adapted for self-running with the clock prior to ride-over, is compared to the phase comparison signal COMP which is the result of the clock detection. Stable clock ride-over is possible by the phase comparison signal COMP having a pulse width larger than the jitter period of the clock subsequent to ride-over.
    Type: Grant
    Filed: November 9, 2000
    Date of Patent: June 14, 2005
    Assignee: NEC Electronics Corporation
    Inventors: Fumio Nakano, Hitoshi Fujita
  • Patent number: 6904080
    Abstract: A receiving circuit has a speech/no-speech signal detector for detecting whether there is a speech signal or not based on data inversely diffused by finger receivers, and a clock controller for controlling operation of the finger receivers based on a detected result from the speech/no-speech signal detector. If a speech signal is detected by the speech/no-speech signal detector, then the clock controller controls all the finger receivers to operate. If no speech signal is detected by the speech/no-speech signal detector, then the clock controller controls only one or two of the finger receivers to operate.
    Type: Grant
    Filed: September 23, 1999
    Date of Patent: June 7, 2005
    Assignee: NEC Corporation
    Inventor: Tomoaki Hokao
  • Patent number: 6888888
    Abstract: Methods and systems for processing a single sub-channel that includes two or more combined channels. Using intermediate frequency sub-sampling, two or more channels from a broad band signal are combined into a single sub-channel for further analog and digital processing. Each of the two or more channels is down converted to an intermediate frequency, filtered to remove certain undesired channels, and combined such that the two or more channels are adjacent to each other. A digital representation of the sub-channel is produced from the combined intermediate frequency channels. Each channel within the digital representation is down converted to baseband, and the in-phase and quadrature components are separated from each other. Compared to one direct down conversion technique, intermediate frequency sub-sampling as described in the application may reduce the number of analog to digital converters and control amplifiers used in analog processing by a factor of four.
    Type: Grant
    Filed: June 26, 2001
    Date of Patent: May 3, 2005
    Assignee: Microsoft Corporation
    Inventors: Dan Q. Tu, Louis F. Coffin, III
  • Patent number: 6885691
    Abstract: A system and method for allocating channelization code and scrambling code in multiple code rates is disclosed. In the present invention, many user signals that have various chip rates in overlaid frequency band can be transmitted with minimum interference between users, by allocating orthogonal spreading code in which the sum of bits for a period that is determined by the ratio of chip rates is canceled respectively, as channelization codes.
    Type: Grant
    Filed: August 1, 2000
    Date of Patent: April 26, 2005
    Assignee: LG Information & Communications, Ltd.
    Inventor: Dug In Lyu
  • Patent number: 6879651
    Abstract: In a data transmission and reception system, a reception-side unit determines a phase adjustment of received relative to a local clock. The reception-side unit includes a means for computing an optimum delay time based, among other data, on externally provided values which are stored locally. In an alternate embodiment of the invention, a transmission-side unit includes a similar mechanism.
    Type: Grant
    Filed: June 26, 2001
    Date of Patent: April 12, 2005
    Assignee: Hitachi, Ltd.
    Inventor: Yuji Saeki
  • Patent number: 6873652
    Abstract: Apparatus and method for establishing a communication link. A negotiation data transmitting section, associated with an initiating communication device, transmits carriers to a responding communication device. A negotiation data receiving section, associated with the plurality of initiating communication devices, receives carriers from the responding communication device, in response to the transmitted carriers. A selecting device selects an appropriate communication device from the plurality of communication devices, in accordance with the responding communication device, in order to establish a communication channel.
    Type: Grant
    Filed: March 31, 1999
    Date of Patent: March 29, 2005
    Assignee: Panasonic Communications Co., Ltd.
    Inventor: Stephen Palm
  • Patent number: 6870882
    Abstract: A MIMO Decision Feedback Equalizer improves operation of a receiver by cancelling the spatio-temporal interference effects caused by the MIMO channel memory with a set of FIR filters in both the feedforward and the feedback MIMO filters. The coefficients of these FIR filters can be fashioned to provide a variety of controls by the designer.
    Type: Grant
    Filed: September 28, 2000
    Date of Patent: March 22, 2005
    Assignee: AT&T Corp.
    Inventors: Naofal Al-Dhahir, Ali H Sayed
  • Patent number: 6870878
    Abstract: An adaptive array radio base station comprises at least three antenna elements (ANTj (j=1, 2, . . . , n)) and a signal processing circuit (20). In calibration, the difference in a phase rotation quantity and the difference in an amplitude fluctuation quantity between a transmission circuit and a receiving circuit in each transmission system are estimated on the basis of a known signal transmitted from each transmission system and a received signal measured in each transmission system. A phase rotation quantity of a phase shifter (PSj) and an amplitude fluctuation quantity of an attenuator (ATTj) are set on the basis of the results of the estimation. Thus provided are a radio apparatus and a calibration method capable of calibrating transmission characteristics of the transmission circuit and the receiving circuit in a simple structure at a low cost without providing a specific measuring circuit.
    Type: Grant
    Filed: August 2, 1999
    Date of Patent: March 22, 2005
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yoshiharu Doi, Toshinori Iinuma
  • Patent number: 6865219
    Abstract: An apparatus and method for performing circular group-wise parallel interference cancellation in a multi-rate DS-CDMA system that reduce the multiple access interference in a CDMA system are disclosed. The invention provide a method of grouping received signals, which improves the interference cancellation efficiency of the signal receiver. The method of the invention groups a plurality of signals according to the magnitude of signals, and sequentially performs interference cancellation with respect to the groups in order of the signal magnitude. The apparatus and method determine the signal rank by using both the power estimation value of the received signal of each finger and the soft bit decision value being the output value of the maximal ratio combiner, perform grouping of the fingers selected by a finger selector, and finally perform interference cancellation. The soft bit decision value is independent of channel, and has the bit information at the time of signal transmission.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: March 8, 2005
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Seong Rag Kim, In Kyeong Choi, Young Wha Kim
  • Patent number: 6865241
    Abstract: An improved data acquisition system interface provides virtually constant sampling of input signals and provides those signals in a digitized format to a data acquisition unit that may not be able to sample at a constant rate without missing or “losing” some of the samples. The present invention acts as a front end interface that temporarily latches the sampled data, expands the data into multiple parallel signals, then stores the multiple parallel signals in a dual-port FIFO memory unit. Finally, the multiple parallel signals are transferred into the data acquisition unit at a lower frequency, and the transfer operations take place only when the data acquisition unit is ready to accept data. Since the front end misses no sampling intervals (i.e., it always takes a sample according to an extremely constant frequency crystal clock), then the data acquisition unit will be provided with all of these samples without losing any data.
    Type: Grant
    Filed: December 15, 1999
    Date of Patent: March 8, 2005
    Assignee: Lexmark International, Inc.
    Inventors: Christopher Alan Adkins, David Allen Crutchfield
  • Patent number: 6862324
    Abstract: Data aided carrier phase and symbol timing synchronizers are implemented at baseband as digital modulators isolating input signal inphase and quadrature component signals fed into inphase and quadrature Laurent transforms that function as data detector to provide odd and even data bit multiplexed output data signal while cross coupling the inphase and quadrature transformed outputs for removing data modulation in error signals to correct phase errors and timing errors in the received signal so as to provide reliable data demodulation of noisy received signals having dynamic carrier phase and symbol timing errors as found in continuous phase modulation communications systems such as Gaussian minimum shift keying communications systems.
    Type: Grant
    Filed: October 23, 2000
    Date of Patent: March 1, 2005
    Assignee: The Aerospace Corporation
    Inventors: Gee L. Lui, Kuang Tsai
  • Patent number: 6862314
    Abstract: To provide a higher data rate service on one link, it is possible to use more than one scrambling code per link. In this way, the same channelization code can be reused and a higher data rate can be supported because the highest data rate is restricted by the set of channelization codes with the shortest length. When reusing one and the same channelization code for spreading the two different data streams transmitted in one link and scrambling these two data streams by two different scrambling codes, the complexity of the receiver will be reduced. Therefore, the two data streams are spread with one and the same channelization code. After this, each of these data streams is scrambled with a different scrambling code.
    Type: Grant
    Filed: October 20, 1999
    Date of Patent: March 1, 2005
    Assignee: Sony International (Europe) GmbH
    Inventors: Jens-Uwe Jürgensen, Richard Stirling-Gallacher