With Specific Filter Structure Patents (Class 455/307)
  • Patent number: 8094759
    Abstract: A system and method to detect broadband pulses in the presence of multiple strong narrow band interferers is disclosed whereby a dynamic filtering method is used to detect and notch out the interfering signal by forming notch filters at the precise location of the narrow band interferers.
    Type: Grant
    Filed: March 10, 2008
    Date of Patent: January 10, 2012
    Assignee: XG Technology, Inc.
    Inventor: Joseph A. Bobier
  • Patent number: 8095095
    Abstract: A band-switch control apparatus for an intermediate-frequency filter comprising: an adjacent interference-signal detecting unit for detecting an adjacent interference-signal, having a frequency adjacent to the desired frequency, superimposed on a reception signal having a frequency tuned to a desired frequency; a modulation-degree detecting unit for detecting a modulation degree of the reception signal; a bandwidth selecting unit for selecting a pass bandwidth of the intermediate-frequency filter corresponding to the amplitude of the adjacent interference-signal; and a band-narrowing suppression control unit for selecting a lower limit value of the pass bandwidth of the intermediate-frequency filter corresponding to the demodulation degree, the intermediate-frequency filter for passing, with a variable pass bandwidth, an intermediate-frequency signal obtained by frequency converting the reception signal, and changing the pass bandwidth selected by the bandwidth selecting unit to the lower limit value, if the
    Type: Grant
    Filed: August 29, 2008
    Date of Patent: January 10, 2012
    Assignee: Semiconductor Components Industries, LLc
    Inventors: Yasuji Saito, Masaya Suto
  • Patent number: 8094025
    Abstract: A receiver architecture for canceling blocking signals in the receive path includes a low noise amplifier for receiving and amplifying an inbound RF signal to produce an amplified inbound signal, in which the inbound RF signal includes a modulated RF signal and a blocking signal, and a cancellation module for substantially canceling the blocking signal from the amplified inbound RF signal and substantially passing the modulated RF signal. The cancellation module cancels the blocking signal by generating an injection signal representative of the blocking signal, combining the blocking signal with the injection signal to produce an error signal, updating the injection signal based on the error signal and using the injection signal to cancel the blocking signal from the amplified inbound RF signal.
    Type: Grant
    Filed: November 9, 2010
    Date of Patent: January 10, 2012
    Assignee: Broadcom Corporation
    Inventors: Aminghasem Safarian, Amin Shameli, Ahmadreza (Reza) Rofougaran, Maryam Rofougaran
  • Publication number: 20120003948
    Abstract: A quadratic amplitude matching system and associated method with an associated tuning control system is provided for continuously and automatically tuning a quadratic amplitude matching filter (QAMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved interference cancellation system performance. The matching control system is provided as an element of an interference cancellation system.
    Type: Application
    Filed: August 15, 2011
    Publication date: January 5, 2012
    Applicant: BAE Systems Information and Electronic Systems Intergration Inc.
    Inventor: Raymond J. Lackey
  • Patent number: 8090339
    Abstract: A tuning control system and associated method is provided for continuously and automatically tuning a lobed amplitude slope matching filter (ASMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved interference cancellation system performance. The tuning control system is provided as an element of an interference cancellation system.
    Type: Grant
    Filed: September 8, 2011
    Date of Patent: January 3, 2012
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Patent number: 8090338
    Abstract: A quadratic amplitude matching system and associated method with an associated tuning control system is provided for continuously and automatically tuning a quadratic amplitude matching filter (QAMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved interference cancellation system performance. The matching control system is provided as an element of an interference cancellation system.
    Type: Grant
    Filed: August 15, 2011
    Date of Patent: January 3, 2012
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Patent number: 8090332
    Abstract: A tracking filter for attenuating out-of-band signals and adjacent channel signals in a receiver is described. In one exemplary design, an apparatus includes a tracking filter, an LNA, and a downconverter. The tracking filter includes a summer, a filter, and an upconverter. The summer subtracts a feedback signal from an input signal and provides a first signal. The LNA amplifies the first signal and provides a second signal. The downconverter frequency downconverts the second signal and provides an output signal. The filter filters (e.g., differentiates) the output signal and provides a third signal. The filter blocks a desired signal and passes out-of-band signal components. The upconverter frequency upconverts the third signal and provides a fourth signal from which the feedback signal is derived. The tracking filter has an equivalent bandpass filter response and a variable center frequency determined based on the frequency of the desired signal.
    Type: Grant
    Filed: December 12, 2007
    Date of Patent: January 3, 2012
    Assignee: QUALCOMM, Incorporated
    Inventors: Gurkanwal Singh Sahota, Chiewcharn Narathong, Ravi Sridhara
  • Publication number: 20110319047
    Abstract: A tuning control system and associated method is provided for continuously and automatically tuning a lobed amplitude slope matching filter (ASMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved interference cancellation system performance. The tuning control system is provided as an element of an interference cancellation system.
    Type: Application
    Filed: September 8, 2011
    Publication date: December 29, 2011
    Applicant: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Publication number: 20110319046
    Abstract: A quadratic amplitude matching system and associated method with an associated tuning control system is provided for continuously and automatically tuning a quadratic amplitude matching filter (QAMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved interference cancellation system performance. The matching control system is provided as an element of an interference cancellation system.
    Type: Application
    Filed: August 15, 2011
    Publication date: December 29, 2011
    Applicant: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Patent number: 8086204
    Abstract: The radio receiving apparatus includes an adaptive receive filter capable of detecting an interference wave and an out-of-band noise level correctly and improving reception performance. The radio receiving apparatus has a plurality of filters, a received signal power meter that measures the overall received signal power, a calculator that performs calculation that associates the measured received signal power with an output of AGC, an interference power meter that measures signal power in a frequency band outside a necessary band of the received signal, a comparator that compares the calculation result by the calculator with a specific threshold, and switches that select a filter to be adopted from the plurality of filters based on the outputs of comparators. The radio receiving apparatus detects adjacent interference based on signal power in the frequency band outside the signal band and detects the noise level based on the power level at an antenna end.
    Type: Grant
    Filed: February 8, 2008
    Date of Patent: December 27, 2011
    Assignee: Panasonic Corporation
    Inventors: Yasutaka Uramoto, Tomohiro Yui
  • Patent number: 8086206
    Abstract: A quadratic amplitude matching system and associated method with an associated tuning control system is provided for continuously and automatically tuning a quadratic amplitude matching filter (QAMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved interference cancellation system performance. The matching control system is provided as an element of an interference cancellation system.
    Type: Grant
    Filed: August 15, 2011
    Date of Patent: December 27, 2011
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Publication number: 20110312294
    Abstract: A channel scanning technique and apparatus provides audio hole suppression in two-way radio communications. Upon detecting the absence of a carrier signal on a priority channel during a priority scan mode of operation, a training waveform is constructed upon returning to the home-channel. The training waveform is applied to audio shaping filters within an audio lineup to suppress transients and minimize or eliminate the occurrence of audio pops at a speaker output thereby reducing the audio hole.
    Type: Application
    Filed: June 16, 2010
    Publication date: December 22, 2011
    Applicant: MOTOROLA, INC.
    Inventors: Geetha K. Thampi, Charles H. Carter, Jesus F. Corretjer, Yadunandana N. Rao
  • Patent number: 8081946
    Abstract: Sampling may be employed to cancel an analog input radio frequency (RF) signal by using an upconverted analog cancellation RF signal to cancel the analog input RF signal at the sample instances. At least two sampling paths may be employed, a signal path and a cancel path, and direct RF bandpass sampling may be included in both the signal and cancel paths.
    Type: Grant
    Filed: December 23, 2008
    Date of Patent: December 20, 2011
    Assignee: L-3 Communications Integrated Systems L.P.
    Inventor: Gerald L. Fudge
  • Patent number: 8078458
    Abstract: A technique is described for concealing the effect of a lost frame in a series of frames representing an encoded audio signal in a sub-band predictive coding system. In accordance with the technique, a first synthesized sub-band audio signal is synthesized, wherein synthesizing the first synthesized sub-band audio signal comprises performing waveform extrapolation based on a stored first sub-band decoded audio signal. A second synthesized sub-band audio signal is also synthesized, wherein synthesizing the second synthesized sub-band audio signal comprises performing waveform extrapolation based on the stored second sub-band decoded audio signal. The first synthesized sub-band audio signal and the second synthesized sub-band audio signal are combined to generate a synthesized full-band output audio signal corresponding to a lost frame.
    Type: Grant
    Filed: May 29, 2009
    Date of Patent: December 13, 2011
    Assignee: Broadcom Corporation
    Inventors: Robert W. Zopf, Jes Thyssen, Juin-Hwey Chen
  • Patent number: 8078130
    Abstract: Systems and methods for interference cancellation in which a first signal having a first frequency may be cancelled with a second frequency having a second and different (e.g., lower) frequency by employing sampling to cancel the first signal with the separate signal at the sample instances.
    Type: Grant
    Filed: December 23, 2008
    Date of Patent: December 13, 2011
    Assignee: L-3 Communications Integrated Systems L.P.
    Inventors: Gerald L. Fudge, Ross E. Bland, Antone L. Kusmanoff
  • Patent number: 8064866
    Abstract: A passive processing device (D) is adapted to be interfaced in a full integrated way on at least a first audio signal path defined between a first audio signal source and an audio signal processing means of an electronic device, such as a mobile communication device. This device (D) comprises a first protection means (DE11; DE12) for rejecting electrostatic discharges on the first path, a first rejection means (CR11, R11; CR12) for rejecting radio signals at least in a chosen frequency band on the first path, and a first AC-coupling means (CC1) for interfacing voltage levels between the first audio signal source and the audio signal processing means.
    Type: Grant
    Filed: June 8, 2005
    Date of Patent: November 22, 2011
    Assignee: NXP B.V.
    Inventor: Bertrand Jean-Louis Le Mellat
  • Publication number: 20110281541
    Abstract: An adaptive front-end architecture for a receiver is disclosed. In one embodiment, the adaptive front-end architecture includes an input configured to receive an input signal and a linear low-noise amplifier connected to the input and configured to amplify the input signal to produce an amplified input signal. The adaptive front-end architecture further includes a first passive mixer arrangement configured to generate first a local oscillator signal and mix the first local oscillator signal with the amplified input signal to produce a first baseband output signal. The adaptive front-end architecture further includes a second passive mixer arrangement configured to generate a second local oscillator signal and mix the second local oscillator signal with the input signal to produce a second baseband output signal. The adaptive front-end architecture further includes a baseband impedance component configured to filter the first baseband signal and/or the second baseband signal using impedance translation.
    Type: Application
    Filed: May 11, 2011
    Publication date: November 17, 2011
    Applicants: RENESAS ELECTRONICS CORP., IMEC
    Inventor: Jonathan Borremans
  • Publication number: 20110261912
    Abstract: One aspect of the present invention is directed to an apparatus to perform impulse blanking of a received signal at multiple locations of a signal processing path. To effect such impulse blanking, multiple impulse detectors and blankets may be present, in addition to other circuitry. The impulse detectors may operate at different bandwidths, and the impulse blankers may be located at different locations of the signal processing path and may be differently configured.
    Type: Application
    Filed: April 27, 2010
    Publication date: October 27, 2011
    Inventor: Junsong Li
  • Patent number: 8045942
    Abstract: A waveform reconstruction circuit receives an rf signal from an antenna, digitizes it, and then generates an undistorted reconstructed waveform. The reconstructed waveform can then be conventionally mixed and demodulated to extract useful signal information with enhanced receiver fidelity and sensitivity.
    Type: Grant
    Filed: February 9, 2010
    Date of Patent: October 25, 2011
    Assignee: American Radio LLC
    Inventor: Robert Hotto
  • Patent number: 8045948
    Abstract: A receiving apparatus includes a receiving portion to receive a radio signal generated based on one baseband signal of a baseband signal having a prescribed frequency band and a baseband signal having a partial frequency band being a part of the prescribed frequency band, a signal processing portion to generate the baseband signal by converting a frequency of the radio signal, a filter portion to output a plurality of partial signals, each having a frequency component of each partial frequency band extracted from the baseband signal generated by the signal processing portion, and an analysis portion to analyze characteristics of each partial signal of the plurality of partial signals output from the filter portion.
    Type: Grant
    Filed: May 28, 2008
    Date of Patent: October 25, 2011
    Assignee: Sony Corporation
    Inventors: Seiichi Izumi, Hiroaki Takahashi
  • Patent number: 8041327
    Abstract: A radio frequency (RF) mixing circuit including a quadrature mixer that receives non-overlapping in-phase and quadrature local oscillator (LO) signals, and a plurality of low noise amplifiers (LNAs) operatively connected to the quadrature mixer, the plurality of LNAs presenting an input impedance at a baseband. A first voltage at an input node of the quadrature mixer is equal to a second voltage across the impedance up-converted to a frequency of a LO signal received by the quadrature mixer. The second voltage across the LNA input impedance includes a frequency of an input signal of the quadrature mixer down-converted by a frequency of the in-phase and quadrature LO signals and filtered by the impedance. The quadrature mixer down-converts an input signal by a frequency of the in-phase and quadrature LO signals and transfers the noise cancelled impedance to a RF to achieve a noise cancelled match.
    Type: Grant
    Filed: June 11, 2008
    Date of Patent: October 18, 2011
    Assignee: Newport Media, Inc.
    Inventor: Edward Youssoufian
  • Patent number: 8036624
    Abstract: A tuning control system and associated method is provided for continuously and automatically tuning a lobed amplitude slope matching filter (ASMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby Providing improved interference cancellation system performance. The tuning control system is provided as an element of an interference cancellation system.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: October 11, 2011
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Patent number: 8036623
    Abstract: This disclosure describes techniques for reducing adverse effects of TX signal leakage in a full-duplex, wireless communication device. The techniques make use of a notch filter to reject TX signal leakage in a signal processed in the RX path of the wireless communication device. The notch filter may be constructed as a complex notch filter using passive resistor and capacitor components to produce a notch frequency that attenuates TX signal leakage components in a desired signal. The notch filter may be applied to a down-converted, baseband signal produced by a passive mixer.
    Type: Grant
    Filed: July 12, 2007
    Date of Patent: October 11, 2011
    Assignee: QUALCOMM, Incorporated
    Inventors: Li-Chung Chang, Prasad S. Gudem, Jose Cabanillas
  • Publication number: 20110244821
    Abstract: Electronic devices contain radio-frequency receivers such as direct conversion receivers. A receiver may receive radio-frequency antenna signals from an antenna in an electronic device. The receiver may include notch filters that attenuate signals in the center of the communications channel that is being received by the receiver. An electronic device may include a clock source. The clock source may be used to clock electrical components in the electronic device. During operation, the clock source may produce radio-frequency interference signals at an associated interferer frequency. The potential for the interference signals to disrupt operation of the receiver can be reduced by configuring the electronic device so that the interferer frequency is aligned with the center of the communications channel. The clock source may be adjusted dynamically to accommodate changes in the communications channel.
    Type: Application
    Filed: March 31, 2010
    Publication date: October 6, 2011
    Inventor: John G. Dorsey
  • Publication number: 20110244822
    Abstract: A receiver 1 is comprised of a first frequency changing circuit 13 for converting a received signal including two or more broadcast waves into a first intermediate frequency signal with a local oscillation, a band separation filter 14 for allowing bands included in the two or more broadcast waves converted into the first intermediate frequency signal to pass therethrough simultaneously, and a second frequency changing circuit 15 for converting the received signal which is outputted by the band separation filter 14 and which is limited to the two or more broadcast waves into a second intermediate frequency signal from which each of the broadcast waves can be sampled at a frequency at which the broadcast waves do not interfere with one another.
    Type: Application
    Filed: November 5, 2009
    Publication date: October 6, 2011
    Inventors: Mitsuru Takeuchi, Eiji Arita
  • Patent number: 8030991
    Abstract: The present invention provides a frequency tuning/DC offset canceling circuit for continuous-time analog filter with time division, the frequency tuning/DC offset canceling circuit including: a frequency tuning/DC offset canceling unit for performing frequency tuning by comparing an output voltage with a reference voltage when a frequency tuning control signal is inputted, and canceling a DC offset after terminating the frequency tuning when a DC offset canceling control signal is inputted; and a control signal generator for generating the frequency tuning control signal and the DC offset canceling control signal based on a reference clock in time division.
    Type: Grant
    Filed: November 6, 2009
    Date of Patent: October 4, 2011
    Assignee: Samsung Electro-Mechanics Co., Ltd.
    Inventors: Sang Hyun Cha, Chang Seok Lee
  • Patent number: 8032103
    Abstract: A tuning control system and associated method is provided for continuously and automatically tuning a lobed amplitude slope matching filter (ASMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved adaptive control loop performance. The tuning control system is provided as an element of an adaptive control loop.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: October 4, 2011
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Patent number: 8023921
    Abstract: A quadratic amplitude matching system and associated method with an associated tuning control system is provided for continuously and automatically tuning a quadratic amplitude matching filter (QAMF) to a band center of an interfering signal to provide improved rejection of an interfering signal coupled from a transmission antenna into a local receive antenna in the presence of local multi-path, thereby providing improved interference cancellation system performance. The matching control system is provided as an element of an interference cancellation system.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: September 20, 2011
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Raymond J. Lackey
  • Patent number: 8024192
    Abstract: A technique is described for use in a decoder configured to decode a series of frames representing an encoded audio signal. The technique is for transitioning between a lost frame and one or more received frames following the lost frame in the series of frames. In accordance with the technique, an output audio signal associated with the lost frame is synthesized. An extrapolated signal is generated based on the synthesized output audio signal. A time lag is calculated between the extrapolated signal and a decoded audio signal associated with the received frame(s), wherein the time lag represents a phase difference between the extrapolated signal and the decoded audio signal. The decoded audio signal is time-warped based on the time lag, wherein time-warping the decoded audio signal comprises stretching or shrinking the decoded audio signal in the time domain.
    Type: Grant
    Filed: August 15, 2007
    Date of Patent: September 20, 2011
    Assignee: Broadcom Corporation
    Inventors: Robert W. Zopf, Juin-Hwey Chen, Jes Thyssen
  • Patent number: 8018273
    Abstract: A filter circuit that removes high-frequency components from an input signal, comprises: an operational amplifier; a first resistor connected between a non-inverting input terminal of the operational amplifier and an input signal source; a first capacitor connected to the non-inverting input terminal of the operational amplifier; a second resistor connected to the non-inverting input terminal of the operational amplifier; a third resistor connected between an inverting input terminal of the operational amplifier and the input signal source; a second capacitor connected between the inverting input terminal of the operational amplifier and an output terminal of the operational amplifier; and a fourth resistor connected to the inverting input terminal of the operational amplifier.
    Type: Grant
    Filed: September 16, 2010
    Date of Patent: September 13, 2011
    Assignee: Onkyo Corporation
    Inventor: Koji Takahama
  • Patent number: 8019308
    Abstract: A receiving apparatus 10 includes a stereo blend control unit 21 for carrying out a stereo blend process according to the reception state of a broadcast wave, a pilot detecting unit 18 for detecting a pilot signal included in the broadcast wave, and a high cut control unit 22 for carrying out high cut control according to the reception state of the broadcast wave and for carrying out the high cut control when the pilot signal is not detected by the pilot detecting unit.
    Type: Grant
    Filed: October 23, 2006
    Date of Patent: September 13, 2011
    Assignee: Mitsubishi Electric Corporation
    Inventors: Takayuki Endo, Hiroyuki Nagahama
  • Patent number: 8014469
    Abstract: A wireless communication device processes N Radio Frequency (RF) bursts contained within N slots of a digital communications time divided frame, wherein N is a positive integer greater than one. The wireless communication device includes an RF front end, a baseband processor, and an equalizer module. The RF front end is operable to receive the plurality of received RF bursts and to convert the RF bursts to corresponding baseband signals. The baseband processor is operable to receive the baseband signals, to pre-equalization process the baseband signals to produce processed baseband signals, and to post-equalization process soft decisions. The equalizer is operable to equalize the processed baseband signals to produce the soft decisions. These RF bursts may be contained in adjacent slots or, in non-adjacent slots, or in a combination of adjacent slots and non-adjacent slots.
    Type: Grant
    Filed: April 23, 2009
    Date of Patent: September 6, 2011
    Assignee: Broadcom Corporation
    Inventors: Baoguo Yang, Li Fung Chang, Zhijun Gong
  • Patent number: 8009728
    Abstract: A parallel equalizer for a DS-CDMA UWB system and method thereof are provided. The parallel equalizer includes: a filter block for filtering a training input signal in a ‘training mode’, and filtering the plurality of input signals in parallel in a ‘symbol decision mode’; a symbol decision block for obtaining a symbol error based on a output from the filter block and a training symbol in the ‘training mode’, and estimating a transmission symbol for each of the input signals in the ‘symbol decision mode’, obtaining an error of one among the estimated transmission symbols for a symbol error calculating input signal; and an weight update block for updating a filter tap coefficients of the filter block based on the training input signal or the symbol error calculating input signal and the symbol error and transmitting the updated filter tap coefficients into the filter block.
    Type: Grant
    Filed: December 8, 2006
    Date of Patent: August 30, 2011
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Kyu-Min Kang, Cheol-Ho Shin, Sung-Woo Choi, Sang-In Cho, Sang-Sung Choi, Kwang-Roh Park
  • Patent number: 8010075
    Abstract: A high-order harmonics generator includes a plurality of high-pass filters to block out DC signals. In one embodiment, high-pass filters are coupled to the output signals from an envelope detector and a power detector. A high-pass filter can also be coupled to the output of a multiplier that multiplies the filtered envelope signal and the filtered power signal. Additional multipliers may also be used at outputs of multipliers in a cascaded chain of multipliers for higher harmonics generation.
    Type: Grant
    Filed: February 26, 2008
    Date of Patent: August 30, 2011
    Assignee: Scintera Networks, Inc.
    Inventor: Frederic Roger
  • Patent number: 8005678
    Abstract: A technique is described herein for updating a state of a decoder configured to decode a series of frames representing an encoded audio signal. In accordance with the technique, an output audio signal associated with a lost frame in the series of frames is synthesized. The decoder state is set to align with the synthesized output audio signal at a frame boundary. An extrapolated signal is generated based on the synthesized output audio signal. A time lag is calculated between the extrapolated signal and a decoded audio signal associated with a first received frame after the lost frame in the series of frames, wherein the time lag represents a phase difference between the extrapolated signal and the decoded audio signal. The decoder state is then reset based on the time lag.
    Type: Grant
    Filed: August 15, 2007
    Date of Patent: August 23, 2011
    Assignee: Broadcom Corporation
    Inventors: Robert W. Zopf, Jes Thyssen, Juin-Hwey Chen
  • Patent number: 8005452
    Abstract: A wideband receiver comprises a comb limiter combiner wherein the limiting is conducted by digitization and frequency excision in the frequency domain. The received signal is divided up into sub-bands by a bank of bandpass filters having contiguous pass bands spanning the entire receiver range. In each sub-band the band limited signal is digitized and subjected to digital signal processing. A threshold is set such that any frequency with a magnitude that exceeds the threshold is excised in the frequency domain. When converted back to the time domain, the high-power interference frequencies will no longer be present, thereby leaving only the low-power noise and the desired signal.
    Type: Grant
    Filed: May 7, 2008
    Date of Patent: August 23, 2011
    Assignee: Sentel Corporation
    Inventor: Michael A. Maiuzzo
  • Patent number: 7999608
    Abstract: Apparatus and methods for providing integrated RF notch filter subsystems having enhanced Q values are described. An integrated notch filter includes an LC filter element and a Q-enhancement circuit coupled to the LC filter element, with the Q-enhancement circuit configured to offset resistive losses in the LC filter element to adjust the Q value of the filter system. A transceiver having multiple LNAs for various bands may be provided to a single notch filter system including a Q-enhancement circuit.
    Type: Grant
    Filed: July 1, 2009
    Date of Patent: August 16, 2011
    Assignee: Quintic Holdings
    Inventors: John B. Groe, Lucio Marc Facchni
  • Patent number: 8000420
    Abstract: A system and method in a radio receiver for joint synchronization and noise covariance estimation of a received signal. A spatially and temporally stacked signal model, whereby successive samples of temporally adjacent received signal vectors and corresponding training vectors are stacked, is used in the derivation of the estimation problem. The Toeplitz structure of the channel response matrix is neglected in the formulation of the estimation problem. The resulting estimator jointly estimates a synchronization position, a channel response matrix, and a noise covariance matrix. An estimate of a whitened channel is then computed based on the noise covariance matrix and the estimate of the channel response matrix.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: August 16, 2011
    Assignee: Telefonaktiebolaget L M Ericsson (PUBL)
    Inventors: Dennis Hui, Abdulrauf Hafeez
  • Patent number: 8000960
    Abstract: A technique is described for concealing the effect of a lost frame in a series of frames representing an encoded audio signal in a sub-band predictive coding system. In accordance with the technique, a first synthesized sub-band audio signal is synthesized, wherein synthesizing the first synthesized sub-band audio signal comprises performing waveform extrapolation based on a stored first sub-band decoded audio signal. A second synthesized sub-band audio signal is also synthesized, wherein synthesizing the second synthesized sub-band audio signal comprises performing waveform extrapolation based on the stored second sub-band decoded audio signal. The first synthesized sub-band audio signal and the second synthesized sub-band audio signal are combined to generate a synthesized full-band output audio signal corresponding to a lost frame.
    Type: Grant
    Filed: August 15, 2007
    Date of Patent: August 16, 2011
    Assignee: Broadcom Corporation
    Inventors: Juin-Hwey Chen, Robert W. Zopf, Jes Thyssen
  • Patent number: 7991379
    Abstract: A radio frequency receiver front-end includes a low noise amplifier, a mixing stage, and a selectable channel filter. The low noise amplifier is operably coupled to amplify inbound RF signals to produce amplified inbound RF signals. The mixing stage is operably coupled to mix amplified inbound RF signals with a 1st local oscillation to produce a 1st intermediate frequency (IF) signal. The selectable channel filter is operably coupled to pass a 1st channel of the 1st IF signal when a channel select signal is in a 1st state and to pass a 2nd channel of the 1st IF signal when the channel select signal is in a 2nd state to produce a selected channel.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: August 2, 2011
    Assignee: ViXS Systems, Inc.
    Inventors: Bojan Subasic, Mathew A. Rybicki
  • Patent number: 7986756
    Abstract: Techniques for filtering noisy estimates to reduce estimation errors are described. A sequence of input values (e.g., for an initial channel impulse response estimate (CIRE)) is filtered with an infinite impulse response (IIR) filter having at least one coefficient to obtain a sequence of output values (e.g., for a filtered CIRE). The coefficient(s) are updated based on the sequence of input values with an adaptive filter, a bank of prediction filters, or a normalized variation technique. To update the coefficient(s) with the adaptive filter, a sequence of predicted values is derived based on the sequence of input values. Prediction errors between the sequence of predicted values and the sequence of input values are determined and filtered to obtain filtered prediction errors. The coefficient(s) of the IIR filter are then updated based on the prediction errors and the filtered prediction errors.
    Type: Grant
    Filed: February 25, 2010
    Date of Patent: July 26, 2011
    Assignee: Qualcomm Incorporated
    Inventors: Gokhan Mergen, Parvathanathan Subrahmanya, Vijayaraj Alilaghatta-Kantharaj, Nitin Kasturi
  • Patent number: 7986932
    Abstract: A fixed point finite impulse response (FIR) filter comprising: 1) an input stage for receiving an input signal as a sequence of input samples comprising: i) delay elements connected in series for receiving and shifting N sequential input samples; ii) multipliers, each multiplier receiving a selected one of the N sequential input samples from the delay elements and multiplying the selected input sample by a corresponding coefficient to produce an intermediate product; and iii) a summer for receiving and adding N intermediate products from the multipliers to produce an output sum signal comprising a sequence of output sum samples; and 2) an output stage for truncating k least significant bits (LSBs) from each of the output sum samples, wherein k is a variable number.
    Type: Grant
    Filed: November 19, 2002
    Date of Patent: July 26, 2011
    Assignee: National Semiconductor Corporation
    Inventor: Tao Zhang
  • Patent number: 7986739
    Abstract: A method and system for detecting the presence of narrowband transmitters utilizing frequencies also utilized by wider band communication systems. In some embodiments an ultrawideband transceiver detects signals at specific frequencies within a spectrum of frequencies, and analyzes the signals to determine if the signals indicate transmissions by a narrowband transmitter in a narrowband communication system. In further embodiments transmission circuitry reduces signal components at frequencies occupied by the narrowband transmitters.
    Type: Grant
    Filed: February 25, 2008
    Date of Patent: July 26, 2011
    Assignee: Realtek Semiconductor Corp.
    Inventors: Turgut Aytur, Stephan ten Brink, Ravishankar H. Mahadevappa, Venkatesh Rajendran
  • Patent number: 7982547
    Abstract: Phase locked loop based frequency tuning of an adjustable filter is disclosed. A resonant circuit includes the adjustable filter, and an oscillator signal provides an input to the resonant circuit.
    Type: Grant
    Filed: March 30, 2009
    Date of Patent: July 19, 2011
    Assignee: Infineon Technologies AG
    Inventor: Stefan Herzinger
  • Patent number: 7983648
    Abstract: The present invention provides a low intermediate frequency receiver for receiving radio frequency signal and provides the sampling method thereof. The low intermediate frequency receiver firstly samples the radio frequency signal so as to convert it into digital signal of non-zero frequency domain. Secondly it compensates the digital signal of non-zero frequency domain to filter out the interfering signal therein. Finally, the compensated digital signal is frequency-shifted to the zero frequency domain. By using the low intermediate frequency receiver and the sampling method thereof according to the present invention, the interference at the zero frequency, like DC drift and intermodulation component, could be easily filtered out without imposing any great influence on the useful signals.
    Type: Grant
    Filed: January 10, 2006
    Date of Patent: July 19, 2011
    Assignee: ST-Ericsson SA
    Inventor: Xuecheng Qian
  • Patent number: 7983644
    Abstract: An apparatus and method for local oscillator calibration compensates for filter passband variation in a mixer circuit, such as a receiver circuit. The receiver includes at least a mixer circuit and a filter coupled to the output of the mixer. During operation, the mixer mixes an RF input signal with a first local oscillator (LO) signal to frequency translate a selected channel in the RF input signal into the passband of the filter. During a calibration mode, the RF input signal is disabled, and the first LO signal is injected into the filter input by leaking the first LO signal through the mixer circuit. The frequency of the LO signal is then swept over a frequency bandwidth that is sufficiently wide so that the actual passband is detected by measuring the signal amplitude at the output of the bandpass filter, thereby determining any variation in the passband of the filter from the expected passband.
    Type: Grant
    Filed: March 15, 2010
    Date of Patent: July 19, 2011
    Assignee: Broadcom Corporation
    Inventors: Donald G. McMullin, Ramon A. Gomez, Lawrence M. Burns, Myles Wakayama
  • Patent number: 7983625
    Abstract: A notch filter suitable for attenuating certain frequencies of a radio-frequency signal includes an input for receiving the radio-frequency signal and an output for the output of a portion of the radio-frequency signal, first and second capacitive means, at least one inductor and a negative resistance circuit suitable for compensating the resistive losses of said at least one inductor. The inductor and the first and second capacitive means are placed to produce a resonator and the filter comprises a control device suitable for controlling the negative resistance circuit. The input impedance of the filter comprises a pole and a zero, with the pole depending on the second capacitive means and the zero depending on both the first and second capacitive means. The first and second capacitive means are variable and the control device is suitable for controlling the first and second capacitive means.
    Type: Grant
    Filed: April 16, 2010
    Date of Patent: July 19, 2011
    Assignee: ST-Ericsson SA
    Inventor: Angelo Granata
  • Patent number: 7983640
    Abstract: A receiver circuit for receiving an analog signal comprises a mixer device, a first integrator device coupled to the mixer device, a second integrator device following the first integrator device, a quantizer device, and first and second feedback digital/analog converters. The mixer device mixes the analog signal with a local-oscillator frequency and outputs a mixer current signal. The first integrator device generates a first intermediate signal by integrating the mixer current signal summed with a first feedback current signal, the second integrator device generates a quantizer input signal by integrating the first intermediate signal summed with a second feedback current signal, and the quantizer device generates a digital output signal by quantizing the quantizer input signal.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: July 19, 2011
    Assignee: Infineon Technologies AG
    Inventor: Lukas Doerrer
  • Publication number: 20110171922
    Abstract: Embodiments of the invention may provide for reducing interference in the front-end of a communications receiver. The cancellation circuitry may be utilized in conjunction with a preliminary rejection filter for improved rejection of out-of-band interference from other radio services or circuitry. The cancellation circuit may be placed in parallel with the preliminary rejection filter and may enhance suppression at the interference frequency by matching the gain and phase of the preliminary rejection filter prior to subtracting the matched signal from the preliminary rejection filter output. The cancellation circuit need not necessary know beforehand the characteristics of the preliminary rejection filter, the interference source, or the coupling mechanism, as it may adapt to unknown or varying interferers by adapting the matching gain and phase values based on the output of the preliminary rejection filter at tap points occurring both before and after application of the cancellation signal.
    Type: Application
    Filed: March 25, 2010
    Publication date: July 14, 2011
    Applicant: SAMSUNG ELECTRO-MECHANICS COMPANY
    Inventors: Andrew Joo Kim, Yunseo Park, Seongmo Yim, Youngsik Hur
  • Patent number: 7979049
    Abstract: A method and apparatus for controlling the power consumption of a receiver based on current operating conditions is described herein. A receiver according to the present invention applies a received signal to a variable filter. The received signal includes a desired in-band signal. Depending on the current operating conditions, the received signal may further include one or more unwanted out-of-band blocking signals. A filter controller controls one or more operating parameters of the variable filter to maintain the power ratio at the filter output of the power of the blocking signal(s) to the in-band signal at or below a desired level. In so doing, the present invention controls the receiver power consumption while still providing the desired receiver performance.
    Type: Grant
    Filed: March 28, 2008
    Date of Patent: July 12, 2011
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Filip Oredsson, Tony Petersson, Lars Sundström