Amplitude Modulation Patents (Class 375/320)
  • Patent number: 7583694
    Abstract: An apparatus and a system, as well as a method and article, may operate to send a selected data type without self-definition information to a receiver if a state capable of interpreting the selected data type has been maintained by the receiver, and to send the selected data type with the self-definition information to the receiver if the state capable of interpreting the selected data type has not been maintained by the receiver.
    Type: Grant
    Filed: December 15, 2003
    Date of Patent: September 1, 2009
    Assignee: Intel Corporation
    Inventor: Adrian P. Stephens
  • Patent number: 7583757
    Abstract: The system in one embodiment relates to tightly integrating parameter estimation, symbol hypothesis testing, decoding, and rate identification. The present invention provides Turbo-decoding for joint signal demodulation based on an iterative decoding solution that exploits error correction codes. The system iteratively couples an initial amplitude estimator, a symbol estimator, a bank of decoders, and a joint amplitude estimator to produce the symbol estimates.
    Type: Grant
    Filed: October 15, 2008
    Date of Patent: September 1, 2009
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Thomas P McElwain
  • Publication number: 20090213922
    Abstract: Where two or more multi-valued digital data symbols are modulated so that they overlap after passing through a channel, forming a combined signal, a receiver receives the combined signal and forms detection statistics to attempt to recover the symbols. Where forming detection statistics does not completely separate the symbols, each statistic comprises a different mix of the symbols. A receiver determines the symbols which, when mixed in the same way, reproduce or explain the statistics most closely. For example, the receiver hypothesizes all but one of the symbols and subtracts the effect of the hypothesized symbols from the mixed statistics. The remainders are combined and quantized to the nearest value of the remaining symbol. For each hypothesis, the remaining symbol is determined. A metric is then computed for each symbol hypothesis including the so-determined remaining symbol, and the symbol set producing the best metric is chosen as the decoded symbols.
    Type: Application
    Filed: March 28, 2008
    Publication date: August 27, 2009
    Inventors: Paul Wilkinson Dent, Gregory E. Bottomley
  • Publication number: 20090213964
    Abstract: A radio detection device includes two or more reception antennas, for detecting a detecting object by a mono-pulse method; the radio detection device including: a variable gain unit for discretely changing respective signal intensity of a difference signal and a sum signal of each reception signal received by the two or more reception antennas; an A/D conversion unit for performing A/D conversion process on the difference signal or the sum signal, the difference signal or the sum signal having the signal intensity changed by the variable gain unit; an angle calculating portion for calculating an angle by the mono-pulse method using the difference signal and the sum signal after the A/D conversion process by the A/D conversion unit; and a control unit for performing a control of individually switching a conversion magnification of the signal intensity by the variable gain unit with respect to the difference signal and the sum signal.
    Type: Application
    Filed: February 20, 2009
    Publication date: August 27, 2009
    Applicant: OMRON CORPORATION
    Inventors: Tetsuo Nishidai, Hideyuki Ohara, Hoshibumi Ichiyanagi, Hiroyuki Numata
  • Patent number: 7580673
    Abstract: In a satellite or other relayed communication system having a plurality of subscriber terminals that communicate through an elevated wireless relay (typically a satellite operating in bent pipe mode), a technique for subscriber terminal power control is provided whereby the power level is controlled via leader-follower operation relying on sharing control factors determined at a single calibrated subscriber terminal transmitter (the leader terminal) to create traffic to be compared to the received traffic of the other subscriber terminals. The power level of the subscriber terminals is then adjusted based on the relationship of their received energy to the received energy of the leader terminal.
    Type: Grant
    Filed: August 7, 2006
    Date of Patent: August 25, 2009
    Assignee: ViaSat, Inc.
    Inventors: Mark J. Miller, John H. O'Neill
  • Patent number: 7577208
    Abstract: A vestigial sideband (VSB) modulation transmission system and, a method for encoding an input signal in the system are disclosed. According to the present invention, the VSB transmission system includes a convolutional encoder for encoding an input signal, a trellis-coded modulation (TCM) encoder for encoding the convolutionally encoded signal, and a signal mapper mapping the trellis-coded signal to generate a corresponding output signal. Different types of the convolutional encoders are explored, and the experimental results showing the performances of the VSB systems incorporating each type of encoders reveals that a reliable data transmission can be achieved even at a lower input signal to noise ratio when a convolutional encoder is used as an error-correcting encoder in a VSB system.
    Type: Grant
    Filed: July 23, 2004
    Date of Patent: August 18, 2009
    Assignee: LG Electronics Inc.
    Inventors: In Hwan Choi, Young Mo Gu, Kyung Won Kang, Kook Yeon Kwak
  • Publication number: 20090185640
    Abstract: A demodulation circuit, a digital microwave system including the demodulation circuit, and a signal demodulation method are provided. The demodulation circuit includes a first circuit, a second circuit, a third circuit, and a fourth circuit connected in turn. The fourth circuit includes a pulse counting unit and a data decision unit connected in turn. The signal demodulation method includes: performing bandpass filtering on input signals; increasing gains of the bandpass filtered signals; extracting pulse signals are extracted from the gain-increased signals; counting the extracted pulse signals; filtering the pulse signals having counting values falling outside of a predetermined range, and outputting the filtered pulse signals.
    Type: Application
    Filed: April 1, 2009
    Publication date: July 23, 2009
    Applicant: HUAWEI TECHNOLOGIES CO., LTD.
    Inventors: Guixue Zhao, Tianxiang Wang
  • Publication number: 20090180576
    Abstract: Embodiments of the present disclosure provide improved techniques for decoding amplitude modulated messages, including those encoded using quadrature amplitude modulation (QAM). For example, a method of decoding amplitude modulation (AM)-encoded messages includes generating a received waveform matrix from a series of receive basis pulses, receiving a multi-dimensional waveform having n AM-encoded messages. The method also includes removing inter-symbol interference from the waveform. In addition, the method includes applying an error-minimizing technique to the received waveform matrix to decode the n AM-encoded messages.
    Type: Application
    Filed: June 13, 2008
    Publication date: July 16, 2009
    Applicant: Rim Semiconductor Company
    Inventor: James Lorin Rulla
  • Patent number: 7555062
    Abstract: A method and device for detecting the amplitude and/or the phase position of an intensity-modulated signal, including the following: detecting an instant value of the intensity-modulated signal and of a first reference signal with a frequency differing from the intensity-modulated signal; mixing the first reference signal with the intensity-modulated signal to obtain a mixed-signal value; detecting an instant value of a second reference signal with a frequency differing from both the previously detected signals and of a third reference signal of the same frequency but phase-shifted from the second reference signal; mixing the mixed-signal value with the second reference signal to yield a first measurement value; mixing the mixed-signal value with the third reference signal to yield a second measurement signal value; and calculating the amplitude and/or phase position from the two measurement signal values.
    Type: Grant
    Filed: September 6, 2005
    Date of Patent: June 30, 2009
    Assignee: PMD Technologies GmbH
    Inventors: Torsten Gollewski, Robert Lange, Thorsten Ringbeck, Holger Heβ, Bernd Buxbaum
  • Publication number: 20090154599
    Abstract: A method (200a-200b), apparatus (104), and computer program for detecting sequences of digitally modulated symbols transmitted by multiple sources (102, 102a-102t) are provided. A real-domain representation that separately treats in-phase and quadrature components of a received vector, channel gains, and a transmitted vector transmitted by the multiple sources (102, 102a-102t) is determined. The real-domain representation is processed to obtain a triangular matrix. In addition, at least one of the following is performed: (i) hard decision detection of a transmitted sequence and demapping of corresponding bits based on a reduced complexity search of a number of transmit sequences, and (ii) generation of bit soft-output values based on the reduced complexity search of the number of transmit sequences. The reduced complexity search is based on the triangular matrix.
    Type: Application
    Filed: July 20, 2006
    Publication date: June 18, 2009
    Inventors: Massimiliano Siti, Michael P. Fitz
  • Publication number: 20090154600
    Abstract: An apparatus includes a receiver configurable to receive signals from y pairs of antennas, where y is greater than one, and where the received signals convey coded bits of information. The apparatus further includes a detection block that includes a plurality of search modules configurable to process signals received from pairs of the antennas in parallel to find partial Euclidian distances and determine valid partial candidates for individual antennas; and a plurality of sort modules configurable to sort the valid partial candidates to find M best partial candidates to be combined into M2 final candidates. The apparatus further includes a plurality of a posteriori probability function units arranged to process the M2 final candidates in parallel, with corresponding final Euclidian distances, to determine a posteriori reliability information for coded bits. As an example, the signals are received from four antennas and are modulated using 16-QAM modulation.
    Type: Application
    Filed: December 14, 2007
    Publication date: June 18, 2009
    Inventors: Kyeong Jin Kim, Predrag Radosavljevic, Joseph R. Cavallaro
  • Patent number: 7545892
    Abstract: Method for controlling an input signal for a contactless transponder, in which a signal strength of an amplitude-modulated input signal is controlled to a nominal value, and identification of a modulation gap by a demodulation device involves control for a controller gain at the time before the modulation gap being stipulated, and identification of the end of the modulation gap involves the control being released after a predetermined interval.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: June 9, 2009
    Assignee: Infineon Technologies AG
    Inventors: Admir Alihodzic, Walter Kargl, Albert Missoni
  • Publication number: 20090141830
    Abstract: A receiver and method for receiving wireless signal are characterized in that a multi-branch correcting and switching module (402) is added, which is used for amplitude and phase correction of multiple digital baseband signals outputted from a multi-branch correction preprocess module (401); then, the signals are switched according to a switching strategy, and one of the corrected digital baseband signals is outputted; finally, the selected digital baseband signal is inputted to a digital receiving path post-stage (403) and further digital processing on the signal is performed, so that a bit stream is outputted. The multiple digital baseband signals are corrected before switching to be consistent with each other in terms of amplitude and phase, and specific synchronization information is not necessary; therefore, the signals can be switched rapidly when the signals are varied and need to be switched, and a rapid track for the signal change is achieved.
    Type: Application
    Filed: November 24, 2008
    Publication date: June 4, 2009
    Applicant: HUAWEI TECHNOLOGIES CO., LTD.
    Inventor: Siqing YE
  • Patent number: 7535291
    Abstract: An amplitude modulation receiver including an antenna for receiving a signal and an input filter connected to the antenna. A variable gain amplifier is connected to the input filter and is responsive to a gain control signal. An A/D converter is connected to the variable gain amplifier and is responsive to a sampling signal and provides a sampled digital signal. A D/A converter receives a demodulated signal and provides an analog output signal. A controller receives and demodulates the sampled digital signal from the A/D converter, generates the gain control signal for the variable gain amplifier, generates the sampling signal for the A/D converter, and provides the demodulated signal to the D/A converter. The demodulation and generation of the gain control signal and the sampling signal are performed in software.
    Type: Grant
    Filed: November 15, 2005
    Date of Patent: May 19, 2009
    Assignee: Sandbridge Technologies, Inc.
    Inventor: Daniel Iancu
  • Publication number: 20090122895
    Abstract: A digital broadcasting transmission and/or reception system having an improved reception performance and a signal-processing method thereof. A digital broadcasting transmitter comprises a TRS encoder for to TRS-encode an MPEG-2 transmission stream having null data for inserting an SRS data and a TRS parity at predetermined positions, randomizer to input and randomize data stream from the TRS encoder, a SRS exchanger to replace the null data for inserting the SRS data to the known data, and an encoder for encoding a data streams to which the Known data is inserted. Accordingly, the present invention detects the known data from a signal received from a reception side and uses the detected known data for synchronization and equalization and further uses the TRS parity for correcting error of the received signal, so that the digital broadcasting reception performance can be improved at poor multipath channels.
    Type: Application
    Filed: October 31, 2008
    Publication date: May 14, 2009
    Inventors: Jung-jin KIM, Yong-deok Chang, Sung-woo Park, Eui-jun Park
  • Publication number: 20090110121
    Abstract: Disclosed are various embodiments of a programmable slicer in a digital signal processing system and/or software radio system. In one embodiment, a plurality of demodulation schemes and a plurality of channel definitions are stored in a channel allocation table. An analog waveform is received and converted into at least one digital waveform. A specified frequency range is isolated from the at least one digital waveform. The magnitude of tones within the specified frequency range is measured and stored in a signal magnitude table. Symbols and/or bits are decoded from the signal magnitude table by applying a demodulation schemes and channel definitions to the magnitudes stored in the signal magnitude table.
    Type: Application
    Filed: October 27, 2008
    Publication date: April 30, 2009
    Applicant: HUNT TECHNOLOGIES, LLC
    Inventors: Damian Bonicatto, Stuart Haug
  • Publication number: 20090110118
    Abstract: A receiver for use in a wireless network comprising a communications channel and a method of allocating deinterleaver memory usage in the receiver, wherein the receiver comprises a processor adapted to organize subchannels of the communications channel and set a number (N) of data bits per soft decision, wherein the soft decision is represented by N data bits; an address decoder adapted to decode the subchannels; a demapper adapted to receive QAM symbols and demap the QAM symbols to soft decisions; a deinterleaver adapted to perform deinterleaving on the soft decisions, wherein the deinterleaver comprises a memory component having a storage size that is a function of the number (N) of bits per soft decision; and a Viterbi decoder adapted to decode the deinterleaved soft decisions.
    Type: Application
    Filed: October 25, 2007
    Publication date: April 30, 2009
    Inventor: Nabil Yousef
  • Publication number: 20090086849
    Abstract: Methods and apparatus for determining the starting points of redundancy version transmissions in a circular rate matching operation. At least one block of information bits to be transmitted are encoded to generate a plurality of coded bits, which are then segmented into a plurality of sub-blocks of coded bits. Each of the sub-blocks of coded bits is interleaved by using a certain interleaver. The interleaved coded bits of the plurality of sub-blocks are collected and filled into a circular buffer having a plurality of redundancy versions in the circular buffer, with each redundancy version corresponding to a starting bit index in the circular buffer. For each transmission, a subset of bits are selected from the circular buffer by selecting a redundancy version from among the plurality of redundancy version. The selected subset of bits are modulated by using a certain modulation scheme, and are transmitted via at least one antenna.
    Type: Application
    Filed: July 7, 2008
    Publication date: April 2, 2009
    Inventors: Jiannan Tsai, Zhouyue Pi, Farooq Khan
  • Patent number: 7502426
    Abstract: An improved system and method for estimating one or more parameters, such as amplitude and signal-to-noise ratio, of a received signal, such as an M-QAM or q-ASK signal, is set forth herein. The amplitude of an M-QAM signal is estimated based upon known or ascertainable phase information regarding a plurality of transmitted symbols. The amplitude of a q-ASK signal is estimated based upon known or ascertainable magnitude information regarding a plurality of transmitted symbols. In another embodiment, the amplitude of an M-QAM or q-ASK signal is estimated based on statistical knowledge of the amplitude of the transmitted symbols. Other embodiments of the present invention estimate amplitude, noise power, and signal-to-noise ratio of a received signal utilizing second-order and fourth-order moments of received samples, a maximum likelihood searching process, or a Kurtosis estimation process.
    Type: Grant
    Filed: December 31, 2003
    Date of Patent: March 10, 2009
    Assignee: InterDigital Technology Corporation
    Inventors: Bin Li, Gregory S. Sternberg, Philip J. Pietraski
  • Publication number: 20090052576
    Abstract: The invention relates to methods for transmitting and receiving a data bit stream in a communication system using 16-QAM constellations. Further, an apparatus for performing the methods is provided. To improve the bit-error rate performance of the communication using the 16-QAM constellations the invention suggests the use 16-QAM constellations with specially selected mapping rules together with a special constellation rearrangement for creating different versions of the 16-QAM constellations. Further, the data stream is transmitted according to a diversity scheme employing different versions of the 16-QAM constellations obtained adhering the mapping rules and rearrangement rules defined by the invention.
    Type: Application
    Filed: May 4, 2005
    Publication date: February 26, 2009
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD
    Inventors: Alexander Golitschek Edler Von Elbwart, Christian Wengerter, Isamu Yoshii
  • Patent number: 7492835
    Abstract: Synchrodyning apparatus in which a PAM IF signal is mixed with unmodulated carriers nominally at the frequency of the carrier, which unmodulated carriers are in quadrature with respect to each other. E.g., the PAM IF signal may be an intermediate-frequency 8VSB digital television signal. The baseband signals resulting from the mixing procedures are additively combined and differentially combined to generate real and imaginary components of a complex baseband signal. The real component of the complex baseband signal is processed for reproducing the digital signal used to modulate the transmitted RF carrier. An automatic frequency and phase control (AFPC) signal for controlling the oscillator circuitry generating the unmodulated carriers is generated by an AFPC detector responding to the imaginary component of the complex baseband signal or to both components of the complex baseband signal.
    Type: Grant
    Filed: September 15, 2005
    Date of Patent: February 17, 2009
    Inventor: Allen LeRoy Limberg
  • Publication number: 20090034658
    Abstract: This invention is primarily a circuit structure of self-mixing receiver, and the methodology of circuit structure is described as follows. The first stage is a high input impedance voltage amplifier utilized to amplify the received RF carrier signal from the antenna. Besides, there are no any inductors required. The second stage is a multi-stage amplifier to amplify the output signal of first stage to rail-to-rail level, which is quite the same with supply voltage. The third stage is a mixer adopted to lower the signal frequency. The fourth stage is a digital output converter, which is proposed to demodulate the electric signals and convert the demodulated signal to digital signal.
    Type: Application
    Filed: December 6, 2007
    Publication date: February 5, 2009
    Inventors: Shey Shi LU, Yu Tso LIN, Fang Ren LIAO
  • Publication number: 20090034590
    Abstract: A method and apparatus to improve modulation efficiency for chip to chip interconnects. Modulation objects that are integer multiples of a fundamental time unit (FTU) are used to populate a symbol period that is also an integer multiple of the FTU. A possible symbol set is established as the set in which the modulation object occupies every possible combination of slots within the symbol period. By permitting the modulation object to overlap positions in different symbols of the set, greater modulation efficiency is achieved.
    Type: Application
    Filed: October 8, 2008
    Publication date: February 5, 2009
    Applicant: Intel Corporation
    Inventor: Larry R. Tate
  • Publication number: 20090022245
    Abstract: A digital demodulation method for a quadrature amplitude modulated signal uses a phase locked loop to generate a local carrier signal. The phase locked loop uses a feedback signal derived from one or more demodulated signals of interest. The loop has a filter characteristic with a stop band within the information bandwidth(s) of the information signal(s). The preferred method generates an error signal from DC components of in-phase and quadrature-phase baseband signals. DC components are preferably isolated using a low-latency, AC rejection filter.
    Type: Application
    Filed: May 24, 2006
    Publication date: January 22, 2009
    Applicant: General Dynamics Advanced Information Systems
    Inventor: Michael G. Binkley
  • Patent number: 7474713
    Abstract: A system and method demodulate N QAM signals (N being a positive integer equal to or greater than 1) substantially simultaneously using, for example, one or two oscillators, regardless of how many QAM signals need to be demodulated.
    Type: Grant
    Filed: August 5, 2005
    Date of Patent: January 6, 2009
    Assignee: Broadcom Corporation
    Inventor: Taruna Tjahjadi
  • Publication number: 20080310551
    Abstract: A 4QAM-NR decoder and decoding method are disclosed. The 4QAM-NR decoder, obtains original data corresponding to receiving data received by a receiving terminal. The 4QAM-NR decoder comprises a determining device, an improving device and a corresponding device. The determining device provides a determining method to determine whether the receiving data is improved or not. The improving device improves the receiving data. The corresponding device obtains the approximate original data corresponding to the receiving data.
    Type: Application
    Filed: January 15, 2008
    Publication date: December 18, 2008
    Inventors: Shih-Hsun Lin, Kin-Ming So
  • Patent number: 7466747
    Abstract: A method and apparatus for wirelessly transmitting data between two devices (101. 102) is provided herein. During data transmission, a data and a strobe signal are transmitted simultaneously on the I and Q-channels, respectively, of over-the-air interface. More particularly, QPSK modulation is utilized, with the strobe signal being transmitted via the I-channel, and the data signal being transmitted via the Q channel, (or vice versa). Additionally, illegal constellation transitions are utilized to signal the transmission of control information.
    Type: Grant
    Filed: December 3, 2004
    Date of Patent: December 16, 2008
    Assignee: Motorola, Inc.
    Inventors: S. David Silk, Jeffrey A. Dykstra, Bruce C. Eastmond
  • Patent number: 7463703
    Abstract: The system in one embodiment relates to tightly integrating parameter estimation, symbol hypothesis testing, decoding, and rate identification. The present invention provides Turbo-decoding for joint signal demodulation based on an iterative decoding solution that exploits error correction codes. The system iteratively couples an initial amplitude estimator, a symbol estimator, a bank of decoders, and a joint amplitude estimator to produce the symbol estimates.
    Type: Grant
    Filed: November 25, 2003
    Date of Patent: December 9, 2008
    Assignee: Bae Systems Information And Electronic Systems Integration Inc
    Inventor: Thomas P McElwain
  • Publication number: 20080298508
    Abstract: An improved receiver and method estimate one or more parameters, such as amplitude and signal-to-noise ratio, of a received signal, such as an M-QAM or q-ASK signal. The amplitude of an M-QAM signal is estimated based upon known or ascertainable phase information regarding a plurality of transmitted symbols. The amplitude of a q-ASK signal is estimated based upon known or ascertainable magnitude information regarding a plurality of transmitted symbols. In another embodiment, the amplitude of an M-QAM or q-ASK signal is estimated based on statistical knowledge of the amplitude of the transmitted symbols. Other embodiments estimate amplitude, noise power, and signal-to-noise ratio of a received signal utilizing second-order and fourth-order moments of received samples, a maximum likelihood searching process, or a Kurtosis estimation process.
    Type: Application
    Filed: July 2, 2008
    Publication date: December 4, 2008
    Applicant: INTERDIGITAL TECHNOLOGY CORPORATION
    Inventors: Bin Li, Gregory S. Sternberg, Philip J. Pietraski
  • Publication number: 20080298509
    Abstract: Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.
    Type: Application
    Filed: July 15, 2008
    Publication date: December 4, 2008
    Applicant: ParkerVision, Inc.
    Inventors: David F. SORRELLS, Gregory S. Rawlins, Michael W. Rawlins
  • Publication number: 20080298507
    Abstract: An electronic quadrature device is provided comprising at least one I signal path (I) and at least one Q signal path (Q); at least one first sigma-delta modulator (DSDMI) and at least one first digital/analog converter unit (DACI) arranged in the at least one I signal path (I); and at least one second sigma-delta modulator (DSDMQ) and at least one second digital/analog converter unit (DACQ) arranged in the at least one Q signal path (Q). The at least one first sigma-delta modulator (DSDMI) is coupled to the at least one second sigma-delta modulator (DSDMQ) via at least one complex signal path (C1-C4) to implement a complex filter.
    Type: Application
    Filed: December 4, 2006
    Publication date: December 4, 2008
    Applicant: NXP B.V.
    Inventors: Lucien Johannes Breems, Robert Rutten, Derk Reefman
  • Publication number: 20080292024
    Abstract: An amplitude-shift-keying radio-frequency (ASK RF) signal decoding method includes separating a low frequency and a high frequency from an ASK RF signal, which includes a pause section and a non-pause section, generating a divided signal by dividing the high frequency signal, counting the divided signal for the non-pause section of the low frequency signal, and decoding the ASK RF signal based on a result of the counting.
    Type: Application
    Filed: May 20, 2008
    Publication date: November 27, 2008
    Inventors: SANG JOO JUN, Ki Yeol Kim, Eui Seung Kim
  • Patent number: 7450666
    Abstract: A delay section delays a detected signal by less than one bit time in the NRZ data. A subtraction section performs subtraction between a delayed signal and the detected signal, and outputs a resultant signal. A clock extraction section extracts, from crossing points of a subtracted signal, crossing points whose time interval is more than or equal to (Tb??) and less than or equal to (Tb+?) (wherein 0<??Tb/8, 0<??Tb: Tb is one bit time in the NRZ data), and outputs a synchronous signal synchronized with the extracted crossing point. A clock recovery section synchronizes a clock signal with the phase of the synchronous signal, and outputs a data clock signal. A determination section determines the polarity of the subtracted signal outputted from the subtraction section in accordance with the data clock signal, and outputs the determination result as the NRZ data.
    Type: Grant
    Filed: October 28, 2004
    Date of Patent: November 11, 2008
    Assignee: Panasonic Corporation
    Inventors: Kenji Miyanaga, Tomohiro Kimura, Kenichi Mori, Hitoshi Takai
  • Patent number: 7446695
    Abstract: A precision pulse detection system for time-of-flight sensors detects a zero axis crossing of a pulse after it crosses above and then falls below a threshold. Transmit and receive pulses flow through a common expanded-time receiver path to precision transmit and receive pulse detectors in a differential configuration. The detectors trigger on zero axis crossings that occur immediately after pulse lobes exceed and then drop below a threshold. Range errors caused by receiver variations cancel since transmit and receive pulses are affected equally. The system exhibits range measurement accuracies on the order of 1-picosecond without calibration even when used with transmitted pulse widths on the order of 500 picoseconds. The system can provide sub-millimeter accurate TDR, laser and radar sensors for measuring tank fill levels or for precision radiolocation systems including digital handwriting capture.
    Type: Grant
    Filed: August 22, 2006
    Date of Patent: November 4, 2008
    Inventor: Thomas Edward McEwan
  • Publication number: 20080267313
    Abstract: Apparatuses and methods for receiving an amplitude modulated signal in one of two modes depending on the quality of the received signal. In a first mode, the amplitude modulated signal is converted directly to a baseband signal. In a second mode, the amplitude modulated signal is converted to an intermediate frequency signal. The present invention advantageously combines direct conversion and image-rejection heterodyne receiver topologies with a relatively large degree of component reuse and relatively few additional components.
    Type: Application
    Filed: April 25, 2007
    Publication date: October 30, 2008
    Inventors: David Meltzer, Gregory A. Blum, Muralikumar A. Padaparambil
  • Patent number: 7444128
    Abstract: A method of estimating the carrier frequency of a signal is disclosed. The method comprising the steps of initializing a time average vector to zero, selecting a user-selectable time segment to divide a received signal into. A signal is received, and divided into the user-selectable time segments. A spectral peak vector is calculated by performing a spectral estimation process on the user-selectable time segment divided signal. A first correlation vector is calculated on the spectral peak vector, and a second correlation vector is calculated from the spectral peak vector and the first correlation vector. The time average vector is appended with the result from the second correlation vector, and the process repeats for each time segment the received signal was broken into. The carrier is estimated using the most commonly occurring frequency in the time average vector.
    Type: Grant
    Filed: January 19, 2006
    Date of Patent: October 28, 2008
    Assignee: The United States of America as represented by the Secretary of the National Security Agency
    Inventor: Douglas J. Nelson
  • Publication number: 20080247490
    Abstract: In a receiver, a synchronization circuit (MIX2, OSC, C1, R1) provides a set of oscillator signals (OSI, OSQ) that are synchronized with a carrier of an amplitude-modulated signal. The set of oscillator signals (OSI, OSQ) comprises a quadrature oscillator signal (OSQ), which is substantially 90° phase shifted with respect to the carrier of the amplitude-modulated signal. A quadrature mixer (MIX2) mixes the quadrature oscillator signal (OSQ) with the amplitude-modulated signal so as to obtain a quadrature mixer output signal (MO2a). A phase-error corrector (PEC) adjusts the phase of the oscillator signals in response to a variation in the magnitude of an alternating current component (AC) in the quadrature mixer output signal (MO2a).
    Type: Application
    Filed: July 26, 2006
    Publication date: October 9, 2008
    Applicant: NXP B.V.
    Inventors: Rob Fortuin, Hubertus J. F. Maas
  • Publication number: 20080232510
    Abstract: Transmit diversity system in which constellation rearrangement is used. Both diversity signals contain the same data and both are 16-QAM, but the location of the data bits within the constellation is different. This averages the effect of the different levels of reliability of the different constellation points. A method for modifying a quadruple of data bits in a data transmission system using Quadrature. Amplitude Modulation with 16 different modulation states, 16-QAM, using an Antipodal Inverted Constellation AICO) mapping, swapping bits selecting contiguous symbol regions with bits selecting non-contiguous symbol regions. Depending on the particular pre-defined mapping and on the particular permutation of bits, inversion of selected bits may be performed in addition. The quadruples thus obtained are mapped to modulation symbols according to a pre-defined AICO mapping.
    Type: Application
    Filed: July 26, 2005
    Publication date: September 25, 2008
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD
    Inventors: Alexander Golitschek Edler Von Elbwart, Christian Wengerter, Isamu Yoshii
  • Publication number: 20080225988
    Abstract: A logarithmic detector circuit including a drive circuit to receive a modulated input signal and generate a buffered modulated signal, a signal shaping circuit coupled to the drive circuit and configured to shape a voltage range of the buffered modulated signal to generate a shaped modulated signal, and a detecting circuit to detect the shaped modulated signal to generate an output signal substantially proportional to a logarithm of an amplitude of the modulated input signal.
    Type: Application
    Filed: March 14, 2007
    Publication date: September 18, 2008
    Applicant: QUANTANCE, INC.
    Inventor: Mark R. Gehring
  • Patent number: 7426243
    Abstract: Systems and methods for receiving non-coherent layered modulation signals are presented. An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal, a processor for decoding the layered in-phase signal and the layered quadrature signal to produce a single layer in-phase signal and a single layer quadrature signal, a digital-to-analog encoder for converting the single layer in-phase signal and the single layer quadrature signal to a single layer in-phase analog signal and a single layer quadrature analog signal and a modulator for modulating the single layer in-phase analog signal and the single layer quadrature analog signal to produce a single layer signal.
    Type: Grant
    Filed: January 2, 2007
    Date of Patent: September 16, 2008
    Assignee: The DIRECTV Group, Inc.
    Inventors: Ernest C. Chen, Tiffany S. Furuya, Philip R. Hilmes, Joseph Santoru
  • Patent number: 7423987
    Abstract: Systems and methods are disclosed for feeder link configurations to layered modulation. One feeder link system employs feeder link spot beam to antennas in distinct coverage areas to enable frequency reuse. Another system employs narrow beam width feeder link antenna to illuminate individual satellites also enabling frequency reuse. Yet another system uses layered modulation in the feeder link. Another feeder link system employs a higher order synchronous modulation for the satellite feeder link than is used in the layered modulation downlink signals.
    Type: Grant
    Filed: October 20, 2003
    Date of Patent: September 9, 2008
    Assignee: The DIRECTV Group, Inc.
    Inventors: Paul R. Anderson, Joseph Santoru, Ernest C. Chen
  • Patent number: 7417496
    Abstract: Provided is a demodulator circuit allowing a tag or transponder to efficiently recover data of an input amplitude signal at very low power in a wireless communication system such as a radio frequency identification (RFID) system. The demodulator connects an output of a voltage multiplier to a low-current path by capacitive coupling, thereby recovering data. Therefore, data is recovered, at low power, from an input amplitude signal having a low modulation depth, and it is possible to increase a communication distance.
    Type: Grant
    Filed: October 27, 2006
    Date of Patent: August 26, 2008
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Tae Young Kang, Kyung Hwan Park, Seong Su Park
  • Publication number: 20080198947
    Abstract: A rf signal transfer link is described which uses amplitude shift keying (ASK) to transfer rf data pulses. The link minimizes state transition time at the end of each data pulse.
    Type: Application
    Filed: February 15, 2007
    Publication date: August 21, 2008
    Inventor: Clemens M. Zierhofer
  • Publication number: 20080181331
    Abstract: A system and method for encoding and receiving data is provided. The data is encoded as a pulse amplitude modulated signal such that the amplitude signals do not transition from the highest signal level to the lowest signal level and do not transition from the lowest signal level to the highest signal level. The encoding and decoding is performed in some embodiments via a lookup table, and in further embodiments is designed to minimize the step between sequential pulse amplitude modulated symbols.
    Type: Application
    Filed: March 24, 2008
    Publication date: July 31, 2008
    Inventors: Bryan K. Casper, Shekhar Y. Borkar, Stephen R. Mooney, Aaron K. Martin, Joseph T. Kennedy, Matthew B. Haycock, James E. Jaussi
  • Publication number: 20080170639
    Abstract: A transmitter modulator that is operable to modulate signals according to multiple modulation formats includes a first modulator, a second modulator, and a polarization beam combiner. The first modulator encodes a first signal according to a first modulation format. The second modulator encodes a second signal according to a second modulation format, the first signal orthogonally polarized with respect to the second signal. The polarization beam combiner combines the first signal and the second signal for transmission.
    Type: Application
    Filed: January 12, 2007
    Publication date: July 17, 2008
    Inventors: Olga I. Vassilieva, Takao Naito
  • Publication number: 20080170641
    Abstract: Multi-carrier modulation fiber optic systems constructed using a series of electrical carriers, modulating the data on the electrical carriers and combining the carriers to form a wideband signal. The wideband signal can then be intensity modulated on a laser and coupled to a fiber optic channel. A receiver may then receive the laser signal from the fiber optic channel and convert it into an electrical signal. Multi-carrier modulation may be applied to existing fiber channels, which may be of lower quality. Existing fiber channels may have characteristics which prevent or restrict the transmission of data using intensity modulation at certain frequencies. An adaptive multi-carrier modulation transmitter may characterize an existing fiber optic channel and ascertain the overall characteristics of the channel. The transmitter and receiver can then be configured to use various bandwidths and various modulations in order to match the transfer characteristic of the fiber channel.
    Type: Application
    Filed: March 25, 2008
    Publication date: July 17, 2008
    Inventor: Oscar E. Agazzi
  • Publication number: 20080112509
    Abstract: The invention relates to a method for determining the sampling instant of a clock signal (ti) for a circuit for determining symbols (Se) from a digitized signal (sd, S) which is coupled to at least one quadrature signal pair of a modulation method (QAM), wherein the digitized signal is converted to polar signal coordinates (R, ?) with a radial component (R). In order to implement an optimization of the sampling instant independently of the frequency or phase offset of the carrier control on which the symbols depend, it is proposed that the rate-of-occurrence distribution of the signals over the radii, which are assigned to the modulation method within the complex plane, be considered at different sampling phases (?i, ?i2) as the quality value (G, G*), and that the better quality value be selected from among the multiple rate-of-occurrence determinations. The variation of the sampling phase assigned to this value is subsequently employed to correct the sampling clock signal (ti).
    Type: Application
    Filed: April 22, 2005
    Publication date: May 15, 2008
    Inventors: Christian Bock, Franz-Otto Witte, Carsten Noeske
  • Publication number: 20080107210
    Abstract: A method for extracting time information from a received, amplitude-modulated time signal is provided. The method provides that the time signal is demodulated, the analog signal thus obtained is digitized by a comparator, and the digital signal thus obtained is analyzed to extract the time information. In addition, a characteristic value of the time duration of at least one signal phase of a specific signal level of the digital signal is compared to a target value, and a comparator threshold of the comparator is altered as a function of a result of the comparison such that the time duration of at least the applicable signal phase of the digital signal approaches the target value. In this way, an improved system sensitivity is achieved according to the invention in a receiver for receiving time signals.
    Type: Application
    Filed: November 27, 2006
    Publication date: May 8, 2008
    Inventor: Horst Haefner
  • Publication number: 20080095273
    Abstract: A method of processing received radio signals in a receiver operating according to the DRM standard, in which the signals are converted to the receiver's baseband frequency, sampled and then subject to Fourier transformation to resolve QAM constellation points, wherein the sample rate of the signal on which the Fourier transform is performed is an integral multiple of the desired frequency spacing in the transform output and the Fourier transformation is a Fast Fourier Transformation.
    Type: Application
    Filed: March 10, 2005
    Publication date: April 24, 2008
    Inventors: Stewart John Hamish Bell, Danny Yuk Kun Wong
  • Patent number: 7363648
    Abstract: An IF input signal corresponding to a selected reception channel is applied through an SAW filter to an IF-AGC circuit, the amplitude of the signal is adjusted to a prescribed level, and the signal is thereafter supplied to a down converter unit. The down converter unit selectively outputs a Low-IF signal provided by down-converting the IF input signal and the High-IF signal amplified without frequency conversion, in accordance with an external instruction. A filter circuit has its cut off frequency selectively set to pass the Low-IF signal only, or both the Low-IF and High-IF signals.
    Type: Grant
    Filed: February 14, 2001
    Date of Patent: April 22, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Syuuji Matsuura