Noise Reduction Or Compensation Patents (Class 329/353)
  • Patent number: 11181409
    Abstract: A monitoring and control system for a flow duct and a method for determining a component status of an operational component disposed within a flow passage of the flow duct utilizing the system are provided. In one exemplary aspect, the system includes at least two sensors that are disposed within the flow passage and configured to sense a characteristic of a fluid flowing therethrough. The sensors may be averaging sensors. Each sensor extends circumferentially about an axial centerline defined by the flow duct. The sensors are arranged in an overlapped arrangement. Particularly, the sensors extend circumferentially about the axial centerline such that the sensors physically overlap one another circumferentially. Additionally, the sensors may be disposed within the same or substantially the same plane axially. Signals generated by the sensors may be utilized to monitor and control the fluid and various operational components disposed within the flow passage.
    Type: Grant
    Filed: August 9, 2018
    Date of Patent: November 23, 2021
    Assignee: General Electric Company
    Inventors: James Ryan Reepmeyer, Gagan Adibhatla
  • Patent number: 10222779
    Abstract: A semiconductor wafer position display system, a semiconductor wafer position display method, and a semiconductor wafer position display program with which a deviation from an appropriate placement position of a semiconductor wafer mounted in a wafer mounting part can be displayed to a user in an easily understood manner are provided.
    Type: Grant
    Filed: March 12, 2015
    Date of Patent: March 5, 2019
    Assignee: Epicrew Corporation
    Inventors: Akira Okabe, Masanori Tanoguchi
  • Patent number: 9363119
    Abstract: A method of FSK decoding includes generating a pulse waveform (R'Edge) from a received FSK encoded signal (FSK signal) and a system clock (Sys_clk). From R'Edge and Sys_clk clocks are generated including a first clock and second clock framing a logic ‘0’ level of the FSK signal, and a third clock and fourth clock framing a logic ‘1’ level of the FSK signal. At least four frequency envelopes are generated from the clocks including a logic ‘0’ envelope, a logic ‘1’ envelope, a lower frequency envelope below the logic ‘0’ envelope, and an upper frequency envelope above the logic ‘1’ envelope. R'Edge is compared to the four envelopes, and a decoded output is produced, logic ‘0’ if the R'Edge overlaps the logic ‘0’ envelope, logic ‘1’ if R'Edge overlaps the logic ‘1’ envelope, and a previous output state if R'Edge does not overlap the logic ‘0’ or logic ‘1’ envelope.
    Type: Grant
    Filed: July 29, 2015
    Date of Patent: June 7, 2016
    Assignee: Honeywell International Inc.
    Inventors: Balakrishna G. Gudi, Dinesh Kumar Kn, Aravind Sathyanarayana, Sandeep Pai
  • Patent number: 9042501
    Abstract: A receiving circuit, use, and method for receiving an encoded and modulated radio signal is provided. The circuit comprise a demodulator and a digital filter connected downstream of the demodulator for moving averaging. The filter has at least two FIFO registers and subtractors. Whereby for subtracting an output value of the FIFO register from an input value of the FIFO register a subtractor is connected to each FIFO register. Wherein the filter has a weighting unit, which is connected downstream of each FIFO register, and wherein the filter has an integrator, which is connected downstream of the subtractors for integration.
    Type: Grant
    Filed: November 14, 2013
    Date of Patent: May 26, 2015
    Assignee: Atmel Corporation
    Inventor: Ulrich Grosskinsky
  • Patent number: 9036742
    Abstract: A demapping scheme, having a low computational cost, suitable for any transmission in which only exhaustive demapping can guarantee good performance. The scheme, proposed in this document, can be used in any transmission based on no differential modulation. For example the proposed scheme can be directly applied to a transmission on flat fading AWGN channels or to a transmission on frequency selective channels after equalization or on each sub-carrier of an OFDM System. The proposed solution can be applied for the demapping of any communication system. The proposed scheme can be used for rotated and un-rotated constellation.
    Type: Grant
    Filed: March 15, 2012
    Date of Patent: May 19, 2015
    Assignee: ALi Europe Sarl
    Inventors: Matteo Butussi, Stefano Tomasin
  • Patent number: 8884691
    Abstract: Disclosed herein is a demodulator, including: a splitting/matching section for carrying out a matching process of making the amplitude and phase of a first modulated signal match respectively the amplitude and phase of a second modulated signal; and a demodulation section for generating a demodulated signal on the basis of the first modulated signal and the second modulated signal, which have been subjected to the matching process carried out by the splitting/matching section, wherein the splitting/matching section has a splitting section, a first matching section, and a second matching section, the first circuit-element constants determining the first input impedance of the first matching section and the second circuit-element constants determining the second input impedance of the second matching section are set at values determined in advance in order to make the first input impedance equal to the second input impedance.
    Type: Grant
    Filed: January 23, 2012
    Date of Patent: November 11, 2014
    Assignee: Sony Corporation
    Inventor: Katsuhisa Ito
  • Patent number: 8831147
    Abstract: A desired signal and interfering signal are transmitted in the same timeslot and on the same frequency using an Adaptive Quadrature Phase Shift Keying (AQPSK) modulated carrier. When the Sub-Channel Power Imbalance Ratio (SCPIR) for the AQPSK modulated carrier is large and favors the interfering signal, the interfering signal is demodulated first to obtain demodulated soft bits. The demodulated soft bits corresponding to the interfering signal are then used to estimate receiver control parameters, such as Doppler shift, frequency offset, timing error, gain, etc. Using the demodulated soft bits corresponding to the interfering signal improves the accuracy of the receiver control parameters when the SCPIR is large, and results in better overall performance of the receiver.
    Type: Grant
    Filed: March 11, 2013
    Date of Patent: September 9, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventors: Naveen Jacob, Amit Singhal
  • Patent number: 8804791
    Abstract: A communication device according to an embodiment of the present invention includes a communication antenna that receives a transmission signal where a spectrum spread signal subjected to a spectrum spread is modulated; an intermediate frequency converting unit that converts the transmission signal received by the communication antenna into an intermediate frequency signal having a predetermined frequency; an analog to digital converting unit that discretizes the intermediate frequency signal and outputs a discretization signal; a noise removing unit that detects a noise other than a normal thermal noise included in the discretization signal and removes the detected noise from the discretization signal; and a demodulating unit that demodulates the spectrum spread signal, based on the discretization signal that is output from the noise removing unit.
    Type: Grant
    Filed: July 15, 2013
    Date of Patent: August 12, 2014
    Assignee: Sony Corporation
    Inventors: Katsuyuki Tanaka, Hideki Takahashi
  • Patent number: 8625723
    Abstract: A method and apparatus for performing demapping in a wireless communication system utilizing a modulo operation are disclosed. The demapping method of a receiver in a wireless communication system includes receiving an input signal and first information indicating whether a first modulo operation is performed on the input signal from a transmitter; if the first information indicates execution of the first modulo operation, performing a second modulo operation of the input signal, and acquiring a reception signal; generating a maximum function value having a highest probability that the reception signal corresponds to a candidate constellation point of an extended constellation; and generating a log-likelihood ratio (LLR) using the generated maximum function value.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: January 7, 2014
    Assignee: LG Electronics Inc.
    Inventors: Wookbong Lee, Inuk Jung, Jinsam Kwak, Kiseon Ryu
  • Patent number: 8594259
    Abstract: A receiving circuit, use, and method for receiving an encoded and modulated radio signal is provided. The circuit comprise a demodulator and a digital filter connected downstream of the demodulator for moving averaging. The filter has at least two FIFO registers and subtractors. Whereby for subtracting an output value of the FIFO register from an input value of the FIFO register a subtractor is connected to each FIFO register. Wherein the filter has a weighting unit, which is connected downstream of each FIFO register, and wherein the filter has an integrator, which is connected downstream of the subtractors for integration.
    Type: Grant
    Filed: February 19, 2010
    Date of Patent: November 26, 2013
    Assignee: Atmel Corporation
    Inventor: Ulrich Grosskinsky
  • Patent number: 8542777
    Abstract: An amplitude modulation (AM) demodulating circuit applied to a radio frequency identification (RFID) system attenuates carrier signals by a notch filter to increase a signal-to-carrier ratio and to reduce complexity and cost of circuit design. The AM demodulating circuit includes an envelope detector, a notch filter, a low-pass filter, and a comparing circuit. The envelope detector performs envelope detection on an AM signal modulated by a carrier frequency to generate an envelope signal. The notch filter filters the envelope signal to generate a first filtered signal, and a zero point of the notch filter corresponds to the carrier frequency of the AM signal. The low-pass filter filters the first filtered signal to generate a second filtered signal, and the carrier frequency of the AM signal corresponds to a stop band of the low-pass filter. The comparing circuit converts the second filtered signal to a digital signal according to a level value.
    Type: Grant
    Filed: January 6, 2011
    Date of Patent: September 24, 2013
    Assignee: MStar Semiconductor, Inc.
    Inventor: Chien-Shan Chiang
  • Patent number: 8503510
    Abstract: A communication device according to an embodiment of the present invention includes a communication antenna that receives a transmission signal where a spectrum spread signal subjected to a spectrum spread is modulated; an intermediate frequency converting unit that converts the transmission signal received by the communication antenna into an intermediate frequency signal having a predetermined frequency; an analog to digital converting unit that discretizes the intermediate frequency signal and outputs a discretization signal; a noise removing unit that detects a noise other than a normal thermal noise included in the discretization signal and removes the detected noise from the discretization signal; and a demodulating unit that demodulates the spectrum spread signal, based on the discretization signal that is output from the noise removing unit.
    Type: Grant
    Filed: July 18, 2012
    Date of Patent: August 6, 2013
    Assignee: Sony Corporation
    Inventors: Katsuyuki Tanaka, Hideki Takahashi
  • Patent number: 8472571
    Abstract: Direct detection of wireless interferers in a communication device for multiple modulation types. One or more radios implemented within a communication device is/are operative to receive and process wireless communications. A wireless communication signal is processed to extract symbols there from. Various symbols groups are processed in accordance with correlation processing to identify potential interferers (e.g., other communication devices using common portions of frequency spectra). Alternatively, matched filter processing (e.g., using a Barker matched filter in some embodiments) operates on the various symbol groups to identify some potential interferers. Various combinations of correlation processing and matched filter processing may be employed in other instances (e.g., using any of a desired means of comparison, combining, etc.) in considering interferers identified in accordance with each of these two means.
    Type: Grant
    Filed: July 23, 2012
    Date of Patent: June 25, 2013
    Assignee: Broadcom Corporation
    Inventor: Prasanna Desai
  • Patent number: 8462894
    Abstract: In a receiver circuit, an analog signal processor frequency-converts an input high frequency signal into a baseband signal, and performs low pass filtering at a cutoff frequency below a desired-wave band. An ADC converts an output of the analog signal processor into a digital signal. A digital signal processor compensates an output of the ADC for a signal component in the desired-wave band which has been attenuated by the filtering operation of the analog signal processor.
    Type: Grant
    Filed: October 14, 2011
    Date of Patent: June 11, 2013
    Assignee: Panasonic Corporation
    Inventors: Yoshifumi Hosokawa, George Hayashi, Ippei Kanno
  • Patent number: 8284869
    Abstract: A method of demodulating a signal on which is modulated, using a quadrature amplitude modulation scheme, a plurality of information symbols, the method including: determining at least one QAM detection threshold corresponding to one or more of said information symbols; and demodulating each information symbol on the basis of at least one respective QAM detection threshold.
    Type: Grant
    Filed: December 12, 2007
    Date of Patent: October 9, 2012
    Assignee: NEC Corporation
    Inventors: Xinhua Wang, Nikolay Vaptzarov, Shikand Satheesh
  • Patent number: 8270546
    Abstract: In a transmission diversity control method in which a request to start or stop transmission diversity is issued by a reception station to a transmission station having a transmission diversity function, the reception station is provided with an equalizer to reduce multipath interference on the basis of a signal correlation, a transmission diversity start request is issued from the reception station to the transmission station when an effect generated by the equalizer is small, and a transmission diversity stop request is issued from the reception station to the transmission station when the effect generated by the equalizer is large.
    Type: Grant
    Filed: February 18, 2010
    Date of Patent: September 18, 2012
    Assignee: Fujitsu Limited
    Inventors: Yasumitsu Ban, Akira Ito
  • Patent number: 8254484
    Abstract: A method of Dirty Paper Coding DPC using nested lattices is disclosed. The complexity of DPC can be reduced by scaling nested lattices and mapping interference to a lattice point of the scaled lattice.
    Type: Grant
    Filed: January 13, 2010
    Date of Patent: August 28, 2012
    Assignees: Samsung Electronics Co., Ltd., The Board of Regents of the University of Texas System
    Inventors: Sung Hwan Kim, Song Soo Hwang, Sang Boh Yun, Sang Hyun Lee, Sung Yoon Jung, Sriram Viswanath
  • Patent number: 8254502
    Abstract: The present patent application discloses a method and apparatus for decoding, comprising decoding signals iteratively, mutually exchanging extrinsic information, calculating APP LLRs for both systematic and parity bits and making a hard decision after a plurality of iterations is completed based on accumulated soft information. The present patent application also discloses a method and apparatus for post decoding soft interference canceling, comprising generating updated a posteriori probabilities for systematic and parity bits from a turbo decoder, mapping the posteriori probabilities to soft symbols, quantizing the soft symbols, re-encoding a data packet, filtering a chip sequence, reconstructing an interference waveform, and scaling reconstruction filter coefficients using the symbols.
    Type: Grant
    Filed: June 18, 2009
    Date of Patent: August 28, 2012
    Assignee: QUALCOMM Incorporated
    Inventors: Sharad D. Sambhwani, Wei Zeng, Wei Zhang, Jan K Wegrzyn, Mehraban Iraninejad
  • Patent number: 8249203
    Abstract: Methods and systems are described for processing a signal in wireless communications. The signal may have synchronization information. A method of processing a signal having synchronization information may include receiving the signal, and determining a truncation region of the time domain estimated channel, the estimated channel having taps. The method further includes processing the channel taps within the truncation region.
    Type: Grant
    Filed: September 22, 2008
    Date of Patent: August 21, 2012
    Assignee: QUALCOMM Incorporated
    Inventors: Thomas Sun, Raghuraman Krishnamoorthi, Fuyun Ling, Krishna Kiran Mukkavilli, Tao Tian, Bojan Vrcelj
  • Patent number: 8243776
    Abstract: A communication device according to an embodiment of the present invention includes a communication antenna that receives a transmission signal where a spectrum spread signal subjected to a spectrum spread is modulated; an intermediate frequency converting unit that converts the transmission signal received by the communication antenna into an intermediate frequency signal having a predetermined frequency; an analog to digital converting unit that discretizes the intermediate frequency signal and outputs a discretization signal; a noise removing unit that detects a noise other than a normal thermal noise included in the discretization signal and removes the detected noise from the discretization signal; and a demodulating unit that demodulates the spectrum spread signal, based on the discretization signal that is output from the noise removing unit.
    Type: Grant
    Filed: February 25, 2009
    Date of Patent: August 14, 2012
    Assignee: Sony Corporation
    Inventors: Katsuyuki Tanaka, Hideki Takahashi
  • Patent number: 8229041
    Abstract: Direct detection of wireless interferers in a communication device for multiple modulation types. One or more radios implemented within a communication device is/are operative to receive and process wireless communications. A wireless communication signal is processed to extract symbols there from. Various symbols groups are processed in accordance with correlation processing to identify potential interferers (e.g., other communication devices using common portions of frequency spectra). Alternatively, matched filter processing (e.g., using a Barker matched filter in some embodiments) operates on the various symbol groups to identify some potential interferers. Various combinations of correlation processing and matched filter processing may be employed in other instances (e.g., using any of a desired means of comparison, combining, etc.) in considering interferers identified in accordance with each of these two means.
    Type: Grant
    Filed: January 8, 2010
    Date of Patent: July 24, 2012
    Assignee: Broadcom Corporation
    Inventor: Prasanna Desai
  • Patent number: 8223907
    Abstract: A method for deriving interference signals from modulated, digital signals is provided. The receiver end reconstructs the modulated digital signals sent by a transmitter. These reconstructed modulated digital signals are then subtracted from the received modulated digital signals, and the result of the subtraction is used to estimate the interference signals without influence by prior filtering at the receiver end. By way of example, it is possible to demodulate the interference signals estimated at the receiver end in order to ascertain possible unauthorized carrier frequencies which disturb the regular carrier frequencies, even if the interference signals are not completely in the bandwidth of the regular carrier frequency or carrier frequencies.
    Type: Grant
    Filed: September 28, 2006
    Date of Patent: July 17, 2012
    Assignee: Siemens AG Österreich
    Inventor: Lukas Pauk
  • Patent number: 8218687
    Abstract: A receiver estimates I/Q imbalance in I and Q input signals using circuitry to separate different frequency components of the I and Q input signals, and estimation circuitry arranged to estimate I/Q imbalance at the different frequency bands. The separating of the bands may be carried out in the frequency domain, and may involve combining corresponding values representing corresponding negative and positive frequency bands, and converting the separated frequency domain representations to a time domain representation before the estimation. The estimated imbalance may be used to correct the I and Q signals at the different frequency bands.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: July 10, 2012
    Assignee: ST-Ericsson SA
    Inventor: Anthony D. Sayers
  • Publication number: 20120119827
    Abstract: Disclosed herein is a demodulator, including: a splitting/matching section for carrying out a matching process of making the amplitude and phase of a first modulated signal match respectively the amplitude and phase of a second modulated signal; and a demodulation section for generating a demodulated signal on the basis of the first modulated signal and the second modulated signal, which have been subjected to the matching process carried out by the splitting/matching section, wherein the splitting/matching section has a splitting section, a first matching section, and a second matching section, the first circuit-element constants determining the first input impedance of the first matching section and the second circuit-element constants determining the second input impedance of the second matching section are set at values determined in advance in order to make the first input impedance equal to the second input impedance.
    Type: Application
    Filed: January 23, 2012
    Publication date: May 17, 2012
    Applicant: Sony Corporation
    Inventor: Katsuhisa Ito
  • Patent number: 8120420
    Abstract: Disclosed herein is a demodulator, including: a splitting/matching section for carrying out a matching process of making the amplitude and phase of a first modulated signal match respectively the amplitude and phase of a second modulated signal; and a demodulation section for generating a demodulated signal on the basis of the first modulated signal and the second modulated signal, which have been subjected to the matching process carried out by the splitting/matching section, wherein the splitting/matching section has a splitting section, a first matching section, and a second matching section, the first circuit-element constants determining the first input impedance of the first matching section and the second circuit-element constants determining the second input impedance of the second matching section are set at values determined in advance in order to make the first input impedance equal to the second input impedance.
    Type: Grant
    Filed: July 27, 2010
    Date of Patent: February 21, 2012
    Assignee: Sony Corporation
    Inventor: Katsuhisa Ito
  • Patent number: 7994852
    Abstract: An electronic circuit includes: a circuit generating first and second balanced differential input signals; a first envelope detection circuit including a first output terminal and first and second input terminals receiving the first and second input signals, respectively, via first and second impedance elements, respectively, and outputs from the first output terminal a first output signal that is the sum of the squares of the first and second input signals; a second envelope detection circuit including a second output terminal and third and fourth input terminals receiving the first and second input signals, respectively, via third and fourth impedance elements, respectively, and outputs from the second output terminal a second output signal that is twice the value obtained by squaring the average of the first and second input signals; and a differential circuit generating a differential signal from the first and second output signals.
    Type: Grant
    Filed: November 17, 2009
    Date of Patent: August 9, 2011
    Assignee: Seiko Epson Corporation
    Inventor: Masayuki Ikeda
  • Patent number: 7932775
    Abstract: A digital demodulation device for demodulating an amplitude modulation (AM) signal whose carrier has a first frequency includes: a processing circuit for performing first path digital processing and second path digital processing according to a second frequency and digital values of the AM signal, where the first path digital processing represents performing down conversion by mixing the AM signal with a first sinusoidal signal whose frequency is equal to the second frequency, the second path digital processing represents performing down conversion by mixing the AM signal with a second sinusoidal signal whose frequency is equal to the second frequency, the second frequency is equal to the first frequency plus a predetermined frequency shift, and the second sinusoidal signal is orthogonal to the first sinusoidal signal; and an output stage for outputting an output signal according to processing results of the first path digital processing and the second path digital processing.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: April 26, 2011
    Assignee: Mediatek Inc.
    Inventor: Yu-Chi Chang
  • Patent number: 7907006
    Abstract: According to one embodiment, a threshold adjusting apparatus for a clocked comparator, the clocked comparator comparing an input signal with a threshold in accordance with a clock, the threshold adjusting apparatus comprises an output detection module configured to detect an output from the clocked comparator with the threshold while changing the threshold and a setting module configured to set the threshold when the output detection module detects a change in the output from the clocked comparator as an adjusted threshold.
    Type: Grant
    Filed: March 6, 2009
    Date of Patent: March 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeyasu Iwata, Toshifumi Yamamoto, Takashi Minemura, Toshiyuki Umeda
  • Patent number: 7864879
    Abstract: A system having a signal processor for detection of a signal type of a signal is disclosed. One embodiment includes a processor designed to determine a first variable which is characteristic of a first spectrum element of the signal spectrum, and to determine a second variable which is characteristic of a second spectrum element of the signal spectrum. A system is provided for determination of a ratio between the first variable and the second variable, and a detector which is designed to detect the signal type on the basis of the ratio.
    Type: Grant
    Filed: February 15, 2007
    Date of Patent: January 4, 2011
    Assignee: Infineon Technologies AG
    Inventors: Xiaofeng Wu, Martin Krueger
  • Patent number: 7724836
    Abstract: In order to compensate for a frequency offset or a change in the phase of the transmission channel over time during mobile radio transmission of data symbols, the data symbols are transmitted by way of carrier-frequency, modulated data bursts. Sample values of the received signal, which are known in advance and correspond to first and second symbols, are evaluated in order to estimate the frequency offset or the change in the phase of the transmission channel over time. These first and second symbols are transmitted with a defined phase angle by way of the data burst, and are arranged separated from one another in the data burst. Edge symbols in a data burst are advantageously used as first and second symbols, or as a symbol pair, for estimation.
    Type: Grant
    Filed: September 7, 2004
    Date of Patent: May 25, 2010
    Assignee: Infineon Technologies AG
    Inventors: Ralf Hartmann, Martin Krüger, Hartmut Wilhelm
  • Patent number: 7623990
    Abstract: A system for reducing signal interference in modulated signal communication includes a measurement processor. The measurement processor measures amplitudes of noise components of a received amplitude modulated signal prior to demodulation. The measurement processor also identifies a frequency of a noise component having an amplitude larger than the amplitude of another noise component. A carrier frequency generator generates a carrier frequency substantially at a harmonic of the identified noise component. The carrier frequency is used to generate and demodulate the amplitude modulated signal.
    Type: Grant
    Filed: November 3, 2005
    Date of Patent: November 24, 2009
    Assignee: Draeger Medical Systems, Inc.
    Inventors: Ralph Anderson, Michael Bernstein
  • Patent number: 7184487
    Abstract: A receiver (202) has a down-conversion receiver (304) for transforming a signal (201) from a first operating frequency to a second operating frequency that is lower than the first operating frequency, and a receiver filter (308) with chopper stabilization for filtering unwanted portions of the signal (306) at the second operating frequency and for generating a final filtered signal (203) at the second operating frequency.
    Type: Grant
    Filed: December 21, 2004
    Date of Patent: February 27, 2007
    Assignee: Motorola, Inc.
    Inventors: Jerry T. Bolton, Jr., Joseph P. Heck
  • Patent number: 6861901
    Abstract: A voltage follower comprising a first field-effect transistor (MN1) whose gate forms the input of the voltage follower. Further provided is a second field-effect transistor (MN2) whose drain connected to the gate forms the output of the voltage follower. The sources of the two field-effect transistors (MN1, MN2) are connected to each other and to the drain of a third field-effect transistor (MN3) serving as current source and to the gate of which a predefined bias voltage is applied. The invention employs in addition a fourth field-effect transistor (MN4) whose source-drain path is circuited between the output of the voltage follower and the drain of the third field-effect transistor (MN3) and whose gate is connected to the gate of the third field-effect transistor (MN3). As compared to prior art voltage followers the voltage follower in accordance with the invention comprises a wider voltage range in which it can be put to use. This can be made use of e.g.
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: March 1, 2005
    Assignee: Texas Instruments Deutschland, GmbH
    Inventors: Franz Prexl, Wolfgang Steinhagen, Ralph Oberhuber
  • Patent number: 6751264
    Abstract: Embodiments of the present invention relate generally to receivers. One embodiment relates to a digital FM receiver having multiple sensors (e.g. antennas). In one embodiment, the digital receiver includes a baseband unit having a channel processing unit. In one embodiment, the channel processing unit is capable of calculating or estimating a phase difference between the incoming signals prior to combining them. One embodiment uses phase estimation method for diversity combining the signals while another embodiment utlizes a hybrid phase lock loop method. Also, some embodiments of the present invention provide for echo-cancelling after diversity combining. An alternate embodiment of the channel processing unit utilizes a space-time unit to diversity combine and provide echo cancelling for the incoming signals.
    Type: Grant
    Filed: July 27, 2001
    Date of Patent: June 15, 2004
    Assignee: Motorola, Inc.
    Inventors: Yui-Luen Ho, Junsong Li, Azfar Inayatullah
  • Patent number: 6590932
    Abstract: Methods, systems and receiver devices are provided which may reduce the average power of a signal disturbance by whitening the signal disturbance. In one aspect, a finite impulse response filter (FIR) is provided which whitens the signal disturbance by filtering a downsampled received signal using filter coefficients adaptively established using known signal information in each signal burst of the received signal. Alternatively, a noise-whitening equalizer is utilized having a modified metric that whitens the signal disturbance again using coefficients adaptively established using known signal information in each signal burst of the received signal. The noise-whitening equalizer approach further allows the noise-whitening coefficients to be updated by treating symbol estimates from the equalizer as known signal information to generate updated noise-whitening coefficients. A novel receiver containing a modified Euclidean metric equalizer to provide noise-whitening is also provided.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: July 8, 2003
    Assignee: Ericsson Inc.
    Inventors: Dennis Hui, Kambiz C. Zangi, Rajaram Ramesh
  • Patent number: 6577182
    Abstract: A device for demodulating a modulated signal resulting from an amplitude modulation of a sinusoidal signal of frequency fo by a signal of frequency fm according to an unknown modulation rate, comprising a transistor (10) where the gate is connected to the modulated signal (Et) so as to obtain in the transistor (10) output a derived signal (St) equal to a power N of the modulated signal, N being an integer greater than 1, and a filter for selecting the frequency component fm in the transistor output signal. The device can be used to demodulate an amplitude-modulated signal received by a scanner of a system identifying contactless portable objects.
    Type: Grant
    Filed: August 27, 2001
    Date of Patent: June 10, 2003
    Assignee: Ask S.A.
    Inventor: Sébastien Morand
  • Patent number: 6442218
    Abstract: The present invention relates to a demodulator which receives a signal transmitted via phase modulation or multivalue QAM modulation, and decides transmitted data based on the received signal. The present invention enhances a transmission-line estimate by using tentatively decided data symbols as pilot symbols and in estimating a transmission line without a decrease in accuracy of transmission-line estimate even when an error rate of the tentatively decided data symbols is increased. The demodulator includes a pilot-based transmission-line estimation unit for estimating transmission-line characteristics by using pilot symbols. A tentative-data-decision unit for tentatively deciding data symbols based on the pilot-based transmission-line estimate. A data-based transmission-line estimation unit for estimating the transmission-line characteristics by using the tentatively decided data.
    Type: Grant
    Filed: August 19, 1999
    Date of Patent: August 27, 2002
    Assignee: Fujitsu Limited
    Inventors: Michiharu Nakamura, Yasuyuki Oishi, Kazuo Nagatani, Hajime Hamada, Yoshihiko Asano, Hiroyuki Seki, Yoshinori Tanaka
  • Patent number: 6400778
    Abstract: A DC-offset canceller in a receiver of a communication system using a burst signal including a training sequence with a predetermined periodicity at the head thereof is disclosed. In the canceller, a quadrature demodulator 112 converts the received burst signal to a base band signal. An AD converter 113 converts an output signal of the quadrature demodulator to a digital signal. A one-cycle delay element 114 makes a delay of an output signal of the AD converter 113 corresponding to one-cycle of the training sequence. A DC-offset detector 115 detects a DC-offset component in the converted signal by the AD converter 113 on the basis of an output signal of the AD converter 113 and an output signal of the one-cycle delay element 114. A subtractor 116 removes the DC-offset component detected by the DC-offset detector 115 from the output signal of the AD converter 113.
    Type: Grant
    Filed: December 4, 1998
    Date of Patent: June 4, 2002
    Assignee: NEC Corporation
    Inventor: Hitosi Matui
  • Patent number: 6075409
    Abstract: A method for demodulating a radio frequency signal having a frequency, by oscillating a demodulator at a frequency different from the signal frequency, and measuring a DC offset value at this different frequency, the DC offset value being associated with interference. Then the demodulator is oscillated at the signal, thereby providing a demodulated signal. The DC offset value is subtracted from the demodulated signal in order to provide a demodulated signal with a substantially reduced DC component. The demodulated signal is then monitored for further DC offset components, and these further DC offset components are subtracted from the demodulated signal.
    Type: Grant
    Filed: April 1, 1999
    Date of Patent: June 13, 2000
    Assignee: Motorola, Inc.
    Inventor: Nadim Khlat
  • Patent number: 5535248
    Abstract: A digital radio communication system includes a first demodulator, a second demodulator, a non-break switch, and a switching controller. The first demodulator receives a signal from a first antenna and outputs demodulated data and a line quality degradation signal. The second demodulator receives a signal from a second antenna and outputs demodulated data and a line quality degradation signal. The non-break switch receives the demodulated data output from the first and second demodulators and selects and outputs one of the demodulated data. The switching controller receives line quality degradation signals output from the first and second demodulators to output a switching control signal to the non-break switch on the basis of the received line quality degradation signals. The first and second demodulators output the line quality degradation signals before the demodulated data are set in an interrupt state when abrupt frequency selective fading occurs.
    Type: Grant
    Filed: December 23, 1994
    Date of Patent: July 9, 1996
    Assignee: NEC Corporation
    Inventor: Yuzo Kurokami
  • Patent number: 5442655
    Abstract: In receiving apparatus of a digital communication system, a received signal burst is demodulated to produce inphase (I) and quadrature (Q) baseband signals which are digitized to provide a set of signal-value pairs for the burst. Each pair consists of an I-value and a corresponding Q-value. The modulation is such that the pairs, if plotted on a complex signal space (I-Q) diagram, would lie substantially on a common circle. To cancel DC offsets in the I and Q signal paths, the average I-value and average Q-value over the burst are found and subtracted respectively from the I- and Q-values of each signal-value pair, to shift the circle so the origin of the I-Q diagram lies within the circle. Then, to restore the DC content of the I and Q signals, the distances I.sub.i1, Q.sub.i2, I.sub.i3 and Q.sub.i4 of signal-value pairs from the I- or Q-axis are averaged in four regions of the I-Q diagram.
    Type: Grant
    Filed: May 27, 1993
    Date of Patent: August 15, 1995
    Assignee: Fujitsu Limited
    Inventors: Ian J. Dedic, Dominic C. Royce
  • Patent number: 5341106
    Abstract: There is described an electronic circuit which operates an Amplitude Locked Loop. The circuit comprises a voltage controlled amplifier, a modulus detector and an integrator combined in a feedback loop. An FM signal decoder is also described as are a number of applications of Amplitude Locked Loop.
    Type: Grant
    Filed: July 22, 1992
    Date of Patent: August 23, 1994
    Assignee: The Governors of Paisley College of Technology
    Inventor: Archibald M. Pettigrew
  • Patent number: 5260974
    Abstract: An improvement in an apparatus which uses a carrier detection threshold level for detecting a carrier signal modulated with binary data. The threshold level is dynamically changed and generally seeks a level above the background noise. The threshold level is maintained constant when the detected signal exceeds the threshold level. An evaluation circuit is able to examine the detected signal to determine whether it contains data or only noise, and if it contains only noise, a possible trapped condition is avoided by raising the threshold level to a level higher than the background noise.
    Type: Grant
    Filed: May 10, 1991
    Date of Patent: November 9, 1993
    Assignee: Echelon Corporation
    Inventors: Howard W. Johnson, Chin-Chen Lee, Amy O. Hurlbut
  • Patent number: 5157343
    Abstract: Electronic receive arrangement for receiving a modulated carrier signal, which arrangement comprises a mixer/demodulator driven with the carrier frequency fc, at least one adder included in a closed signal loop, a low-pass filter, and a pulse shaper constituted by a sigma-delta (one-bit) signal converter and driven with the sampling frequency fs and also comprises a digital decimation filter. The signal loop includes the mixer/demodulator so that the modulated carrier signal is applied to the adder and the output signal of the adder is applied to the mixer/demodulator. The signal loop also comprises a second mixer driven with frequency fc, and the frequencies fs and fc present a common multiple.
    Type: Grant
    Filed: May 31, 1991
    Date of Patent: October 20, 1992
    Assignee: U.S. Philips Corporation
    Inventor: Johannes O. Voorman
  • Patent number: 5097222
    Abstract: There is disclosed a system and method for demodulating an analog signal using digital conversion of the analog signal. In one embodiment the incoming modulated signal is digitally sampled and a calculation is made as to both the short term and long term energy of the digitized version of the analog signal. The deviation between the short and long term energy levels is used to determine the amount of modulation of the incoming analog signal. An analog demodulated signal is then reconstructed from the digitized deviation calculations. In an alternate embodiment, a digital signal processor is used to derive the demodulated signal.
    Type: Grant
    Filed: July 18, 1991
    Date of Patent: March 17, 1992
    Assignee: Texas Instruments Incorporated
    Inventor: Peter R. Dent