Balancing Or Cancelling Patents (Class 455/284)
  • Patent number: 10097230
    Abstract: Systems and methods relating to improving transmit (TX) port to receive (RX) port isolation of a duplexer or multiplexer are disclosed. In some embodiments, a system includes a duplexer or multiplexer having a transmit port, a receive port, and an antenna port. The system further includes a leakage cancellation subsystem adapted to cancel a leakage signal from the TX port of the duplexer or multiplexer to the RX port of the duplexer or multiplexer across a desired cancellation bandwidth. The leakage cancellation subsystem compensates for variation of the leakage signal across the desired cancellation bandwidth, thereby improving TX port to RX port isolation over conventional systems.
    Type: Grant
    Filed: April 27, 2016
    Date of Patent: October 9, 2018
    Assignee: Qorvo US, Inc.
    Inventor: Gernot Fattinger
  • Patent number: 10015792
    Abstract: Provided are an electronic device and method for avoiding interference between frequencies therefor. The electronic device may include: a housing; a wireless communication circuit arranged in the housing; at least one electronic component arranged in the housing; a processor electrically connected with the wireless communication circuit and the at least one electronic component; and a memory electrically connected with the processor. The memory may store instructions that, when executed, cause the processor to send or receive a signal to or from the at least one electronic component using a first frequency, to send or receive a signal to or from an external device through the wireless communication circuit using a second frequency, and to determine whether to change the first frequency in consideration of the second frequency. Other embodiments are possible.
    Type: Grant
    Filed: September 23, 2016
    Date of Patent: July 3, 2018
    Assignee: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Hoon Choi, Jonghyeok Youn
  • Patent number: 8977226
    Abstract: A mobile terminal including a transceiver having a plurality of output terminals; a plurality of power amplifier units respectively connected to the plurality of output terminals, and configured to amplify a first or second signal output by the output terminals and to output the amplified first or second signal to a plurality of antennas respectively connected the plurality of power amplifiers; and a receiving module configured to receive a third signal through a receiving antenna disposed to be spaced apart from the plurality of antennas and to output the received third signal to the transceiver. Further, the receiving module includes first and second filters configured to control an intermodulation distortion (IMD) signal included in the third signal due to the output of the first or second signal.
    Type: Grant
    Filed: January 2, 2013
    Date of Patent: March 10, 2015
    Assignee: LG Electronics Inc.
    Inventor: Hoonyong Kim
  • Patent number: 8929848
    Abstract: An interference-robust receiver includes an RF signal processor, a frequency conversion interface and an analog signal processor. The RF signal processor provides an RF signal. The frequency conversion interface includes a passive mixer for generating an intermediate frequency signal by down-converting an in-band part of the RF signal to a passband of a filter and down-converting an out-of-band part of the RF signal to a stopband of the filter. The filter can thus filter the intermediate frequency signal with the passband and the stopband.
    Type: Grant
    Filed: November 5, 2009
    Date of Patent: January 6, 2015
    Assignee: MediaTek Singapore Pte. Ltd.
    Inventors: George Chien, Yen-Horng Chen, Chi-Yao Yu, Lan-Chou Cho, Chih-Chun Tang, Siu-Chuang Ivan Lu
  • Patent number: 8909166
    Abstract: An apparatus and method for controlling a multi-band antenna in a mobile communication terminal are provided. An apparatus for controlling a multi-band antenna in a mobile communication terminal includes a modem, an antenna unit, a Radio Frequency (RF) processing unit, and a switch module. The modem outputs at least one control signal corresponding to a target frequency band. The antenna unit changes a resonance frequency of the antenna according to the at least one control signal. The RF processing unit includes a plurality of transmission/reception (TX/RX) paths and processes TX/RX signals. The switch module connects the antenna to one of the TX/RX paths according to the at least one control signal.
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: December 9, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jung-Ho Park, Sung-Hwan Ko, Suk-Chan Hong, Young-Hwan Jung
  • Patent number: 8843098
    Abstract: The present invention provides a filter that may be used as a reconstruction filter with a built-in balun. One embodiment of the filter includes first and second input nodes for receiving balanced radiofrequency signals and an inductive-capacitive (LC) circuit coupled between the first and second input nodes and first and second intermediate nodes. This embodiment of the filter also includes a coupling circuit that couples the first and second intermediate nodes to an output node. Balanced signals within a filter bandwidth are transmitted from the first and second input nodes to the output node and balanced signals outside the filter bandwidth are substantially shorted to ground.
    Type: Grant
    Filed: June 10, 2011
    Date of Patent: September 23, 2014
    Assignee: Alcatel Lucent
    Inventor: Michael G. Zierdt
  • Patent number: 8749354
    Abstract: Disclosed is an RFID system that includes a controller that outputs the transmission signal to be transmitted to an RFID tag and reads a receiving signal transmitted from the RFID tag; a leakage signal canceller that receives a portion of the transmission signal and the receiving signal, and performs an adjustment task to generate a cancellation signal according to an adjustment value and the portion of the transmission signal to remove a transmission leakage signal and to remove the transmission leakage signal included in the receiving signal; and a reader controller that determines whether there is a change of an RF environment using an intensity of the receiving signal according in a period set in advance, controls an operation of the leakage signal canceller according to the change of the RF environment, and controls an operation of the controller to read the receiving signal transmitted from the RFID tag.
    Type: Grant
    Filed: May 9, 2011
    Date of Patent: June 10, 2014
    Assignee: LSIS Co., Ltd.
    Inventor: Yeong Chan Kim
  • Patent number: 8742898
    Abstract: Disclosed is an apparatus for removing a transmission leakage signal of an RFID system including a reader controller that sends a transmission signal to an RFID tag and receives a receiving signal transmitted from the RFID tag to read tag information, the apparatus including a leakage signal canceller that receives a portion of the transmission signal and the receiving signal, and performs an adjustment task to generate a cancellation signal according to an adjustment value to remove a transmission leakage signal and the portion of the transmission signal, and to remove the transmission leakage signal included in the receiving signal and a controller that continuously determines whether there is a change of an RF environment using an intensity of the receiving signal, the RFID tag being installed in the RF environment, and controls an operation of the leakage signal canceller according to the change of the RF environment.
    Type: Grant
    Filed: May 9, 2011
    Date of Patent: June 3, 2014
    Assignee: LSIS Co., Ltd.
    Inventor: Yeong Chan Kim
  • Patent number: 8718589
    Abstract: Method and apparatuses are disclosed to substantially compensate for various unwanted interferences and/or distortions within a communications receiver. Each of these apparatuses and methods estimate the various unwanted interferences and/or distortions within the communications receiver. Each of these apparatuses and methods remove the estimates of the various unwanted interferences and/or distortions within the communications receiver from one or more communications signals within the communications receiver to substantially compensate for the various unwanted interferences and/or distortions.
    Type: Grant
    Filed: June 30, 2011
    Date of Patent: May 6, 2014
    Assignee: Broadcom Corporation
    Inventors: Ramon Alejandro Gomez, Bruce J. Currivan, Massimo Brandolini, Young Shin, Francesco Gatta, Hanli Zou, Loke Kun Tan, Lin He, Thomas Joseph Kolze, Leonard Dauphinee, Robindra Joshi, Binning Chen
  • Patent number: 8718584
    Abstract: A dual conversion receiver architecture that converts a radio frequency signal to produce a programmable intermediate frequency whose channel bandwidth and frequency can be changed using variable low-pass filtering to accommodate multiple standards for television and other wireless standards. The dual conversion receiver uses a two stage frequency translation and continual DC offset removal. The dual conversion receiver can be completely implemented on an integrated circuit with no external adjustments.
    Type: Grant
    Filed: July 6, 2010
    Date of Patent: May 6, 2014
    Assignee: MaxLinear, Inc.
    Inventors: Kishore Seendripu, Raymond Montemayor, Curtis Ling, Glenn Chang, Sheng Ye
  • Patent number: 8693528
    Abstract: In one or more embodiments, a circuit is configured to receive a differential signal from a transmitter that is isolated from the receiver circuit and that includes a common-mode suppression circuit and signal combining circuit coupled to the corresponding lines carrying the differential signals. The common-mode suppression and signal combining circuits are configured to suppress common-mode signals of differential signals communicated on the set of differential signal lines and combine to form of differential-mode components of the differential signals.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: April 8, 2014
    Assignee: NXP B.V.
    Inventors: Rameswor Shrestha, Hendrik Boezen, Martin Bredius
  • Patent number: 8606210
    Abstract: A polyphase harmonic rejection mixer, comprising a plurality of stages following each other; wherein a first stage is arranged to perform at least frequency conversion; and a second stage is arranged to perform at least selective weighting and combining; wherein at least two of the plurality of stages are arranged to perform at least combining. In an embodiment, the first stage (28) comprises three single-ended gain blocks (10, 12, 14), arranged to perform selective weighting, frequency conversion and combining; and a second stage (30) following the first stage (28) and arranged to perform selective weighting and combining. The second stage (30) may reduce the number of phases output by the first stage (28) and may output (32) a complex differential down converted signal. The mixer may be directly interfaced to an antenna of an LNA-less receiver without weighting in the first stage. The mixer may be included in a software-defined radio.
    Type: Grant
    Filed: February 3, 2010
    Date of Patent: December 10, 2013
    Assignee: NXP, B.V.
    Inventors: Zhiyu Ru, Eric A. M. Klumperink, Bram Nauta, Johannes H. A. Brekelmans
  • Patent number: 8588285
    Abstract: A digital subscriber line arrangement includes a downstream modem, an upstream modem and a copper pair connection between the modems. Each modem includes electrical length estimation function code means which causes the respective modem to measure the attenuation of signals transmitted by the other modem at a plurality of different frequencies, and to combine these measurements, or functions thereof, together to form a combined attenuation measure and to use this combined measure to form an electrical length estimation, KL0bis. The downstream modem is operable to transmit its electrical length estimation to the upstream modem, and the upstream modem is operable to generate a definitive electrical length estimation in dependence upon both the received estimation from the downstream modem and the estimation made by the upstream modem. Having generated a definitive electrical length estimation, the upstream modem is operable to transmit this to the downstream modem.
    Type: Grant
    Filed: April 1, 2011
    Date of Patent: November 19, 2013
    Assignee: British Telecommunications Public Limited Company
    Inventors: Leslie Derek Humphrey, Andrew David Wallace
  • Patent number: 8553751
    Abstract: A radio equipment controller includes a calculator that calculates a delay amount by subtracting from a given maximum delay amount an internal delay amount of a radio equipment and a delay amount of a cable, the radio equipment modulating and transmitting orthogonal frequency division multiplexing (OFDM) symbols, and the cable connecting the radio equipment and the radio equipment controller that creates the OFDM symbols, a detector that detects a beginning of the OFDM symbols from data that is inputted into a buffer that stores data of the OFDM symbols, and a delay controller that determines a transmission timing of the OFDM symbols so that the transmission timing of the beginning of the OFDM symbols becomes a timing that is delayed by the calculated delay amount after a reference signal with a specific period.
    Type: Grant
    Filed: March 1, 2012
    Date of Patent: October 8, 2013
    Assignee: Fujitsu Limited
    Inventor: Shinichiro Kobayashi
  • Publication number: 20130115894
    Abstract: A receiver compensation method comprising receiving a radio frequency signal, amplifying the radio frequency signal, thereby producing an amplified signal, compensating the amplified signal, thereby producing a compensated signal, and mixing the compensated signal, thereby producing a mixed compensated signal, wherein the mixed compensated signal has a first gain difference between a positive differential from a center frequency and a negative differential from the center frequency and wherein the first gain differential is smaller than a second gain differential that would be obtained by mixing the amplified signal without compensating the amplified signal.
    Type: Application
    Filed: November 2, 2012
    Publication date: May 9, 2013
    Applicant: FUTUREWEI TECHNOLOGIES, CO.
    Inventor: FUTUREWEI TECHNOLOGIES, CO.
  • Patent number: 8363712
    Abstract: An I/Q imbalance compensation block of a RF receiver for compensating an imbalance between an in-phase component and a quadrature component of an RF signal is disclosed. The compensation block includes a conjugation block; an adaptive finite impulse response (FIR) filter; and an adder. The filter use filter coefficients iteratively updated at least partly in response to a compensated digital signal. The filter can have a complex number for at least one, but not all of filter taps, and real numbers for other filter taps. The filter can be provided with adaptation step sizes different from filter tap to filter tap. The filter can also be provided with an adaptation step size(s) varying over time. The filter can also be provided with an adaptation step size(s) divided by the square norm of the compensated signal.
    Type: Grant
    Filed: January 6, 2011
    Date of Patent: January 29, 2013
    Assignee: Analog Devices, Inc.
    Inventor: Raju Hormis
  • Patent number: 8364100
    Abstract: Methods and systems for a transmitter LOFT cancellation scheme that maintains IQ balance are disclosed. Aspects of one method may include providing current compensation to both differential inputs of a mixer for each of I and Q channels. An initial current compensation of X units may be provided, followed by subsequent compensation as needed. The initial compensation may be provided to each differential input of the mixers used for I and Q channels. The subsequent current compensation for the I channel may be independent of the subsequent current compensation for the Q channel. Subsequent current compensation to a first differential input for a mixer may be increased by Y units while decreasing current compensation to the second differential input of the mixer by Y units. In this manner, the DC common mode level for the mixer may remain the same at the initial DC compensation current of X units for both mixers.
    Type: Grant
    Filed: June 3, 2010
    Date of Patent: January 29, 2013
    Assignee: Broadcom Corporation
    Inventor: Meng-An Pan
  • Patent number: 8346198
    Abstract: In one embodiment, the present invention includes an amplifier having a transistor stage coupled between a supply voltage and a bias current. The transistor stage has an input to receive a radio frequency (RF) input signal obtained from an antenna. The amplifier has an input impedance that is unmatched to a source impedance of the antenna. In some embodiments, this unmatched input impedance may be substantially greater than the source impedance, and may further be controlled based on a strength of the RF input signal.
    Type: Grant
    Filed: June 30, 2005
    Date of Patent: January 1, 2013
    Assignee: Silicon Laboratories Inc.
    Inventors: Dan B. Kasha, G. Tyson Tuttle, Gregory A. Hodgson
  • Patent number: 8280314
    Abstract: A method for compensating a transceiver for impairments includes transmitting a plurality of partial bandwidth training signals using a transmitter. A plurality of response signals of a receiver having a bandwidth and exhibiting receiver impairments is captured. Each response signal is associated with one of the partial bandwidth training signals. Each of the partial bandwidth training signals is associated with a portion of the receiver bandwidth. A plurality of partial compensation filters is generated based on the plurality of response signals. Each partial compensation filter is associated with one of the response signals. The partial compensation filters are combined to configure a receiver compensation filter operable to compensate for the receiver impairments.
    Type: Grant
    Filed: June 30, 2009
    Date of Patent: October 2, 2012
    Assignee: Alcatel Lucent
    Inventors: Michael Steven Heutmaker, Walter Honcharenko
  • Patent number: 8270907
    Abstract: Aspects of a method and system for matching an integrated system to an antenna utilizing on-chip measurement of reflected signals are provided. In a chip comprising at least a portion of a receiver and at least a portion of a transmitter, a best impedance match between an antenna and the chip may be determined based on on-chip measurement of one or more signals reflected from the antenna. The best impedance match between the antenna and the chip may be determined utilizing a correction algorithm. The correction algorithm may be determined utilizing data from an external test set that measures signals transmitted by the chip via the antenna. The reflected signals may be routed to a signal analyzer via on on-chip directional coupler. The best impedance match may be determined for each of a plurality of frequencies and/or each of a plurality of transmit signal strengths.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: September 18, 2012
    Assignee: Broadcom Corporation
    Inventor: Thomas Baker
  • Patent number: 8254834
    Abstract: A radio frequency identification (RF) system includes an RF reader, an RF tag, and a network connection module. The RF reader includes a reader radio frequency (RF) bus transceiver. The network connection module includes a network connection RF bus transceiver, wherein the reader RF bus transceiver exchanges at least one of inbound RF data and outbound RF data with the network RF bus transceiver via an RF bus.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: August 28, 2012
    Assignee: Broadcom Corporation
    Inventor: Ahmadreza (Reza) Rofougaran
  • Patent number: 8194718
    Abstract: In the reception and demodulation of a communication signal with frequency hopping among a plurality of frequency bands, a demodulator is formed by a balance circuit. The demodulator performs frequency conversion by multiplying signals in_a and in_b, which are obtained by converting a received signal into differential signals, by local signals Lo—1a and Lo—1b with a frequency corresponding to a frequency band of the received signal, which are frequency-switched during a guard interval period of the received signal, in synchronization with a symbol of the received signal. Further, two output ends of the demodulator are charged/discharged through capacitors in synchronization with frequency switching of the local signal so that a voltage difference between the two output ends of the demodulator becomes a prescribed level.
    Type: Grant
    Filed: April 1, 2008
    Date of Patent: June 5, 2012
    Assignee: Renesas Electronics Corporation
    Inventor: Hideo Ohba
  • Patent number: 8131245
    Abstract: A mixer for downconversion of RF signals includes at least one RF transistor (305); at least one switching pair (303) connected to the drain current (301) of the at least one RF transistor (305); and a common mode sensing component (300) configured to detect deviations in the common mode output of the switching pair (303) from a specified output; wherein the deviations modify the current of the at least one switching pair (303).
    Type: Grant
    Filed: September 13, 2007
    Date of Patent: March 6, 2012
    Assignee: Cambridge Silicon Radio Limited
    Inventors: Niels Christoffers, Nicolas Sornin
  • Patent number: 8131226
    Abstract: A high-frequency circuit comprising a high-frequency switch circuit for switching the three-way connection of an antenna to a transmitting circuit for the first communications system, a receiving circuit for a first communications system, and a transmitting/receiving circuit for a second communications system; a first bandpass filter disposed between the antenna and the high-frequency switch circuit; and a balanced-unbalanced conversion circuit disposed between the receiving circuit of the first communications system and the high-frequency switch circuit.
    Type: Grant
    Filed: December 6, 2005
    Date of Patent: March 6, 2012
    Assignee: Hitachi Metals, Ltd.
    Inventors: Shigeru Kemmochi, Kazuhiro Hagiwara, Keisuke Fukamachi, Takahiro Yamashita, Masayuki Uchida, Mitsuhiro Watanabe
  • Patent number: 8121571
    Abstract: A transceiver device that performs an intercept point calibration using signal interferers is described. The signal interferers include at least self-generated signal interferers or opportunistic signal interferers in surrounding areas. Due to non-linearity in the transceiver device, intermodulation distortion (IMD) signal components are generated. Filtering of the IMD signal components is performed to allow low-frequency components, such as a second order intermodulation (IM2) to pass through. A dynamic minimization algorithm is performed to minimize distortion effects of the low-frequency components.
    Type: Grant
    Filed: December 18, 2009
    Date of Patent: February 21, 2012
    Inventors: Igal Kushnir, Ofir Degani, Lior Kravitz, Alexander Rivkind
  • Patent number: 8019312
    Abstract: An apparatus, method, and system for DC offset cancellation are provided herein. For instance, the apparatus can include a first commutating mixer switch and a second commutating mixer switch. The first commutating mixer switch can have a first input port configured to receive a first differential signal and a first differential output port. The second commutating mixer switch can have a second input port configured to receive a second differential offset signal and a second differential output port. The first and second differential output ports can be coupled to one another to provide a combined differential output signal.
    Type: Grant
    Filed: August 20, 2009
    Date of Patent: September 13, 2011
    Assignee: Broadcom Corporation
    Inventor: Tzi-Hsiung Shu
  • Patent number: 7925220
    Abstract: Aspects of a method and system for matching an integrated FM system to an antenna utilizing on-chip measurement of reflected signals are provided. In this regard a portion of a signal output by an integrated FM radio transmit block and reflected by an antenna may be routed to an on-chip signal analyzer. Accordingly, measurements of the reflected signals may be utilized to configure a matching network in order to provide a best impedance match between the FM radio and the antenna. In this regard, a best impedance match may maximize radiation efficiency and/or radiated power. Additionally, the configuration of the matching network may incorporate a correction algorithm/offset experimentally determined via a calibration utilizing external components.
    Type: Grant
    Filed: August 1, 2007
    Date of Patent: April 12, 2011
    Assignee: Broadcom Corporation
    Inventor: Thomas Baker
  • Patent number: 7907891
    Abstract: Embodiments of a repeater environment can be operative to deploy a feedback cancellation loop that is adaptively coupled with an antenna array such that a selected metric can be applied to the antenna array and feedback cancellation loop combination to improve signal integrity and amplification. Illustratively, the feedback cancellation loop of the exemplary repeater can be adapted by a metric that operatively adapts weights provided by performing a selected linear algebra technique to the feedback cancellation loop such that the metric can be indicative of the level of transmitter signal present at a receive and can be derived based on performing a correlation between the transmitted signal and the receiver signal. Further, operatively, the exemplary repeater can maintain a delay sufficient to preferably ensure that transmitted signal is de-correlated with the desired receiver signal, and time aligned and correlated with the feedback leakage signal.
    Type: Grant
    Filed: March 3, 2008
    Date of Patent: March 15, 2011
    Assignee: QUALCOMM Incorporated
    Inventors: James A. Proctor, Jr., Kenneth M. Gainey, James C. Otto
  • Patent number: 7865202
    Abstract: Aspects of a method and system for I/Q branch equalization in OFDM systems may include determining a transfer function mismatch between an in-phase processing branch, and/or a quadrature processing branch in an OFDM receiver. The determined transfer function mismatch may be compensated for, by applying equalization after a fast Fourier transform (FFT) in an in-phase processing branch and/or a quadrature processing branch. The OFDM system may be compliant with, for example, UMTS LTE (EUTRA), WiMAX (IEEE 802.16), DVB-H, and WLAN (IEEE 802.11). A transfer function may be measured for an in-phase branch filter and/or quadrature branch filter to determine the transfer function mismatch. The transfer function mismatch may be compensated for, in frequency domain by the equalizer. The transfer function mismatch may comprise magnitude and/or phase response mismatch, wherein the magnitude and/or phase response mismatch may be a function of frequency.
    Type: Grant
    Filed: October 15, 2008
    Date of Patent: January 4, 2011
    Assignee: Broadcom Corporation
    Inventors: Francis Swarts, Mark Kent, Theodoros Georgantas
  • Patent number: 7778613
    Abstract: A dual conversion receiver architecture that converts a radio frequency signal to produce a programmable intermediate frequency whose channel bandwidth and frequency can be changed using variable low-pass filtering to accommodate multiple standards for television and other wireless standards. The dual conversion receiver uses a two stage frequency translation and continual DC offset removal. The dual conversion receiver can be completely implemented on an integrated circuit with no external adjustments.
    Type: Grant
    Filed: April 13, 2005
    Date of Patent: August 17, 2010
    Assignee: MaxLinear, Inc.
    Inventors: Kishore Seendripu, Raymond Montemayor, Curtis Ling, Glenn Chang, Sheng Ye
  • Patent number: 7773966
    Abstract: A mobile terminal capable of breaking a phase-noise signal caused by a high power transmission signal of a mobile phone such as GSM when receiving digital TV broadcasting such as DVB-H and a method of reducing interfering phase-noise in the mobile terminal. The mobile terminal includes a first RF transmitter/receiver; a first signal coupler; a phase-noise filter; a phase shifter; a VGA amplifier; and a signal combiner.
    Type: Grant
    Filed: May 11, 2007
    Date of Patent: August 10, 2010
    Assignee: Samsung Electro-Mechanics Co., Ltd.
    Inventors: Won Wook So, Hak Sun Kim, Won Tae Choi, Young Kyu Park, Joo Yul Ko
  • Patent number: 7756501
    Abstract: A multipass noise detecting apparatus comprising: a smoothing process unit configured to receive input of a signal corresponding to electric field strength of a received signal and to smooth the signal; a delay process unit configured to delay the signal; an amplifying unit configured to amplify a signal output from the smoothing process unit; a pulse noise determining unit configured to compare a signal output from the delay process unit with a signal output from the amplifying unit to output a pulse noise determining signal indicating a period of presence of pulse noise; and a noise cancel process unit configured to carry out a process for removing pulse noise on the basis of the pulse noise determining signal, the process being applied to the signal output from the delay process unit.
    Type: Grant
    Filed: June 22, 2007
    Date of Patent: July 13, 2010
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yasuji Saito, Masaya Suto
  • Patent number: 7734259
    Abstract: Methods and systems for a transmitter LOFT cancellation scheme that maintains IQ balance are disclosed. Aspects of one method may include providing current compensation to both differential inputs of a mixer for each of I and Q channels. An initial current compensation of X units may be provided, followed by subsequent compensation as needed. The initial compensation may be provided to each differential input of the mixers used for I and Q channels. The subsequent current compensation for the I channel may be independent of the subsequent current compensation for the Q channel. Subsequent current compensation to a first differential input for a mixer may be increased by Y units while decreasing current compensation to the second differential input of the mixer by Y units. In this manner, the DC common mode level for the mixer may remain the same at the initial DC compensation current of X units for both mixers.
    Type: Grant
    Filed: December 28, 2006
    Date of Patent: June 8, 2010
    Assignee: Broadcom Corporation
    Inventor: Meng-An Pan
  • Patent number: 7689170
    Abstract: A radio frequency (RF) receiver and receiving method are provided which can remove a leakage component from a received signal by using a local signal. In the RF receiver, a noise removing unit controls a gain and a phase of a local signal LOI according to a phase THETA and a gain AMPTD detected in a MODEM, estimates a signal Vcal corresponding to a noise component introduced into a received RF signal RXIN, and removes the estimated signal Vcal from the received RF signal RXIN. In this manner, a clean RF signal RXO, which does not include a noise component, is frequency-down converted in a receiving unit.
    Type: Grant
    Filed: May 1, 2006
    Date of Patent: March 30, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ick Jin Kwon, Heung Bae Lee
  • Patent number: 7680456
    Abstract: Methods, apparatus, and articles of manufacture are disclosed for removing an undesired component from a low intermediate frequency signal having an intermediate center frequency and an undesired component at a first frequency. One example method may include determining an amplitude of the undesired component; frequency shifting the low intermediate frequency signal from the intermediate center frequency to produce a zero intermediate frequency signal; filtering the zero intermediate frequency signal; generating a tone based on the amplitude of the undesired component; and subtracting the tone from the filtered zero intermediate frequency signal to remove the undesired component.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: March 16, 2010
    Assignee: Texas Instruments Incorporated
    Inventors: Khurram Muhammad, Imtinan Elahi
  • Patent number: 7596362
    Abstract: A mixer for a radio transceiver includes a commutating mixer switch having a first differential input port coupled to a DC offset cancellation path. The first differential input port of the mixer switch includes a first terminal coupled to a first end of a first resistor and a second terminal coupled to a first end of a second resistor. Second ends of the first and second resistors are configured to receive a differential input signal. The DC offset cancellation path may provide a resistively coupled DC calibration signal for reducing the magnitude of DC offsets that may be present at the input of the mixer switch. The concept can be used for either image or non-image reject mixers.
    Type: Grant
    Filed: May 1, 2006
    Date of Patent: September 29, 2009
    Assignee: Broadcom Corporation
    Inventor: Tzi-Hsiung Shu
  • Patent number: 7548739
    Abstract: A receiver apparatus includes a preamplifier to amplify an input signal, an equalizer configured to subject an amplified signal to an equalization process, an identification reproducer to reproduce the input signal based on an output signal of the equalizer, and a magnetic oscillator arranged on a pre-stage of the preamplifier to improve a SN ratio of the input signal.
    Type: Grant
    Filed: September 23, 2005
    Date of Patent: June 16, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Rie Sato
  • Patent number: 7546107
    Abstract: A high frequency receiver capable of stably canceling interference by a transmission signal even if a transmission signal input from a TV antenna is changed. Phase shifter (212) for changing a phase of an interfering distributed transmission signal, detector (216) for detecting a level of a transmission signal included in a receive signal input via an antenna, and level regulator (213) for changing a level of the distributed transmission signal in accordance with this level are provided. A signal input via level regulator (213) and phase shifter (212) and a receive signal are synthesized to be input into mixer (206). Since a transmission signal can be cancelled even if a transmission signal input from an antenna is changed, a high frequency receiver can receive a signal stably when a transmission signal is changed.
    Type: Grant
    Filed: December 13, 2005
    Date of Patent: June 9, 2009
    Assignee: Panasonic Corporation
    Inventors: Masaaki Noda, Motoyoshi Kitagawa
  • Patent number: 7526265
    Abstract: Embodiments of a receiver impairment estimation and correction system and method that can be implemented in a low intermediate frequency receiver system are disclosed. In one embodiment, among others, a method for operating a receiver is disclosed that comprises receiving a radio frequency signal, downconverting the radio frequency signal to a downconverted signal comprising an in-phase component and quadrature-phase component, buffering the downconverted signal in a memory, estimating receiver impairments associated with the in-phase component and the quadrature-phase component for a defined time period, and compensating for the receiver impairments for each defined time period.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: April 28, 2009
    Assignee: Skyworks Solutions, Inc.
    Inventors: Norman J. Beamish, William J. Domino, Morten Damgaard
  • Publication number: 20090093228
    Abstract: Embodiments of the present invention include circuits and methods for reducing DC Offset. In one embodiment the present invention includes storing DC offset on internal capacitances. In one embodiment, parallel stages are used to remove DC offset corresponding to different local oscillator frequencies. Embodiments of the invention further include changing the low cutoff frequency of the DC cancellation circuits for fast calibration. In a first state, a high pass filter may have a first low cutoff frequency, and in a second state the high pass filter may have a second cutoff frequency lower than the first low cutoff frequency. The present invention also includes a variable gain amplifier with reduced DC offset.
    Type: Application
    Filed: December 9, 2008
    Publication date: April 9, 2009
    Applicant: WiLinx Corporation
    Inventors: Edris Rostami, Alireza Mehrnia, Rahim Bagheri, Masoud Djafari
  • Patent number: 7515894
    Abstract: A system and a method for wireless communications includes an antenna, a GPS circuit with a GPS matching circuit that is coupled to the antenna, a communications circuit with a communications matching circuit that is coupled to the antenna. The communications matching circuit is adapted to switch between different impedances, for example, to match the communications circuit with the antenna for a particular communications band or to isolate the communications circuit from the antenna. The communications matching circuit or the GPS matching circuit may be actively adapted.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: April 7, 2009
    Assignee: Kyocera Wireless Corp.
    Inventor: Ray Wallace
  • Patent number: 7502603
    Abstract: Improved DC cancellation in zero-IF receivers for eliminating the DC offset that otherwise would be caused by the AC voltage on a coupling capacitor at the time of switching from AC coupling to DC coupling. The coupling capacitor normally is connected first as a high pass filter to block any DC component, and then directly coupled as a direct or DC coupler. However any AC component of voltage on the coupling capacitor at the moment of switching normally remains as a DC offset. In accordance with the invention, the component of AC voltage on a coupling capacitor is tracked, and when switched to DC coupling, the component of AC voltage on the capacitor at the time of switching is held and subtracted from the signal path, thereby canceling the DC offset component that otherwise would be caused. Alternate embodiments are disclosed, including embodiments for accelerating capacitance charging for speed-up of the method.
    Type: Grant
    Filed: June 3, 2005
    Date of Patent: March 10, 2009
    Assignee: Maxim Integrated Products, Inc.
    Inventor: Rishi Mohindra
  • Patent number: 7483683
    Abstract: Rejection of local oscillator harmonic response is provided in a mixing circuit with a pair of harmonic gating switches serially connected to the outputs of a balanced differential switching mixer and controlled by a gate clock signal having twice the frequency of a local oscillator signal controlling the switching mixer. An aperture or duty cycle of the gate clock signal determines which harmonic is rejected or suppressed, which is preferably a third and/or fifth harmonic since response of the balanced differential switching mixer to even harmonics is negligible. The resulting simple, efficient circuit is readily integrated directly into a phase-alternating mixer structure for a chopper-direct-conversion radio.
    Type: Grant
    Filed: August 3, 2007
    Date of Patent: January 27, 2009
    Assignee: National Semiconductor Corporation
    Inventors: Hee Wong, Michael Schwartz, James Braatz, Shu-Ing Ju
  • Patent number: 7477885
    Abstract: Embodiments of the present invention include circuits and methods for reducing DC Offset. In one embodiment the present invention includes storing DC offset on internal capacitances. In one embodiment, parallel stages are used to remove DC offset corresponding to different local oscillator frequencies. Embodiments of the invention further include changing the low cutoff frequency of the DC cancellation circuits for fast calibration. In a first state, a high pass filter may have a first low cutoff frequency, and in a second state the high pass filter may have a second cutoff frequency lower than the first low cutoff frequency. The present invention also includes a variable gain amplifier with reduced DC offset.
    Type: Grant
    Filed: April 22, 2005
    Date of Patent: January 13, 2009
    Assignee: Wilinx Corporation
    Inventors: Edris Rostami, Alireza Mehrnia, Rahim Bagheri, Masoud Djafari
  • Patent number: 7437135
    Abstract: At least one communication is transmitted from a plurality of transmitting antennas. A signal is received. For each transmitting antenna, the received signal is equalized with respect to a channel experience by the communication between the transmitting antenna and the signal receiving, producing symbols. A contribution of that transmitting antenna to the received signal is constructed using the produced symbols. The contribution of that transmitting antenna is subtracted from the received signal for use in further equalization of the received signal with respect to others of the transmitting antennas.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: October 14, 2008
    Assignee: InterDigital Technology Corporation
    Inventors: Jung-Lin Pan, Robert A. DiFazio, Yingming Tsai
  • Publication number: 20080081551
    Abstract: An embodiment of the present invention provides an apparatus, comprising a radio frequency identification transceiver adapted for self jammer suppression. The transceiver may further comprise a phase shifter and variable attenuator/variable amplifier adjusted to minimize the power injected into a receive chain by the self jammer. In an embodiment of the present invention the present transceiver may further comprise at least one RF peak power detector to determine the power injected into the receive chain.
    Type: Application
    Filed: September 26, 2006
    Publication date: April 3, 2008
    Inventor: Joshua Posamentier
  • Publication number: 20070298749
    Abstract: A multipass noise detecting apparatus comprising: a smoothing process unit configured to receive input of a signal corresponding to electric field strength of a received signal and to smooth the signal; a delay process unit configured to delay the signal; an amplifying unit configured to amplify a signal output from the smoothing process unit; a pulse noise determining unit configured to compare a signal output from the delay process unit with a signal output from the amplifying unit to output a pulse noise determining signal indicating a period of presence of pulse noise; and a noise cancel process unit configured to carry out a process for removing pulse noise on the basis of the pulse noise determining signal, the process being applied to the signal output from the delay process unit.
    Type: Application
    Filed: June 22, 2007
    Publication date: December 27, 2007
    Applicant: Sanyo Electric Co., Ltd.
    Inventors: Yasuji Saito, Masaya Suto
  • Publication number: 20070259638
    Abstract: An analog baseband circuit includes first and second DC (direct current) offset cancellers and an offset canceller controller. The first DC offset canceller includes a first filter and a first PGA (programmable gain amplifier) with a first gain step for eliminating a first dc component from an input baseband signal. The second DC offset canceller includes a second filter and a second PGA with a second gain step less than the first gain step for eliminating a second dc component from an output of the first DC offset canceller. The offset canceller controller controls the first and second filters to operate in a fast mode when a gain of the first PGA is changed.
    Type: Application
    Filed: April 20, 2007
    Publication date: November 8, 2007
    Inventors: Jae-Wan Kim, Young-Jin Kim, Jae-Heon Lee
  • Patent number: 7269391
    Abstract: A transceiver front end includes a transmit/receive (T/R) switch, a first balun, a second balun, a low noise amplifier, a power amplifier, and compensation circuitry. The T/R switch is operably coupled to an antenna for receiving inbound radio frequency (RF) signals and for transmitting outbound RF signals. The first balun includes a single ended winding and a differential winding, where the single ended winding is operably coupled to the T/R switch. The second balun includes a single ended winding and a differential winding, where the single ended winding is operably coupled to the T/R switch. The low noise amplifier is operably coupled the differential winding of the first balun. The power amplifier is operably coupled to the differential winding of the second balun. The compensation circuitry is operably coupled to the first balun to compensate for at least one of phase imbalance, amplitude imbalance, and impedance imbalance of the first balun.
    Type: Grant
    Filed: May 24, 2004
    Date of Patent: September 11, 2007
    Assignee: Broadcom Corporation
    Inventors: Janice Chiu, Shahla Khorram, Qiang (Tom) Li
  • Patent number: 7228120
    Abstract: A method is provided for reducing a DC bias in a receiver. This method includes isolating a second circuit portion from a first circuit portion (535) and determining a second DC bias correction value for the second circuit portion that will eliminate a second DC bias at the isolated second circuit portion (540). The second circuit portion is then connected to the first circuit portion (550) and a bias-maximizing code word is generated at the first circuitry (505). A first DC bias correction value is then determined that will eliminate a first DC bias at the first circuit portion (555). The bias-maximizing code word is formed such that: a first integrated value of a first half of the bias-maximizing code word has a positive value, and a second integrated value of a second half of the bias-maximizing code word over half of the code word length has a negative value.
    Type: Grant
    Filed: November 18, 2004
    Date of Patent: June 5, 2007
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Terence L. Johnson, Nitin Sharma, Ryan W. Lobo