With Specific Filter Structure Patents (Class 455/307)
  • Publication number: 20140155013
    Abstract: A circuit for baseband harmonic rejection includes multiple transconductance cells coupled to one another at outputs of the transconductance cells and configured to receive down-converted signals that vary from one another to produce a weighted current signal proportional to a voltage corresponding to a respective down-converted signal. The circuit also includes a feedback impedance coupled between an input of one of the transconductance cells and the outputs of the transconductance cells. Each of the transconductance cells has an effective transconductance of a first magnitude for frequency components of the down-converted signal arising from a first harmonic and an effective transconductance of a second magnitude less than the first magnitude for frequency components of the down-converted signal arising from harmonics at integer multiples of the first harmonic.
    Type: Application
    Filed: January 4, 2013
    Publication date: June 5, 2014
    Applicant: Broadcom Corporation
    Inventors: David MURPHY, Hooman Darabi
  • Patent number: 8737542
    Abstract: A method and apparatus for receiving data in high-speed applications wherein an analog-to-digital converter (ADC) samples a received signal and a data decoder implemented with a tree search algorithm detects the bits of the sampled data for timing recovery. In some embodiments, a Viterbi detector is implemented to provide accurate bit detection for data output while tree search detected data is used to determine the optimal sampling phase for the ADC. In some embodiments, after the phase acquisition stage of timing recovery has completed, the tree search decoder may decrease the rate of data detection to maintain phase tracking.
    Type: Grant
    Filed: January 7, 2011
    Date of Patent: May 27, 2014
    Assignee: Marvell International Ltd.
    Inventor: Jagadish Venkataraman
  • Publication number: 20140141737
    Abstract: An anti-jamming system includes a tunable negative jamming signal feedback loop for feedback suppression of a received jamming signal. The system includes a zero IF phase locked loop (PLL) jamming signal receiver having a synchronous demodulator and a phase detector. A VCO is included in the PLL, as well as a phase detector and a loop filter. A replica jamming signal generator includes a tracking modulator with a baseband signal input coupled to an output of a synchronous demodulator in the receiver and a carrier input provided by the VCO. An output of the tracking modulator is negatively fed back to the input of the receiver to suppress the jamming signal in the received input.
    Type: Application
    Filed: November 17, 2012
    Publication date: May 22, 2014
    Inventor: Wolfdietrich Georg KASPERKOVITZ
  • Patent number: 8731486
    Abstract: Provided is a high-frequency module that can prevent a transmission signal from reaching a reception circuit and that can achieve high mounting density. A first duplexer for a first frequency band is mounted on a circuit substrate, and a second transmission filter and a second reception filter that constitute a second duplexer for a second frequency band are embedded in the circuit substrate. The second transmission filter and the second reception filter are embedded in the circuit substrate in locations that overlap at least a part of a projection region that is formed by projecting the first duplexer in a thickness direction of the circuit substrate. The first frequency band and the second frequency band are separated from each other by at least a prescribed frequency range.
    Type: Grant
    Filed: October 18, 2013
    Date of Patent: May 20, 2014
    Assignee: Taiyo Yuden Co., Ltd.
    Inventors: Tetsuo Saji, Hiroshi Nakamura
  • Patent number: 8731504
    Abstract: A method of filtering and a RF filtering circuit comprising a LO adapted to generate in-phase and quadrature LO signals; a quadrature passive mixer operatively connected to the LO; a filtering impedance operatively connected to the quadrature passive mixer, wherein the voltage at an input node of the quadrature passive mixer comprises the voltage across the filtering impedance up-converted to a frequency of a LO signal received by the quadrature passive mixer. Preferably, the voltage across the filtering impedance comprises a frequency of an input signal of the quadrature passive mixer down-converted by a frequency of the in-phase and quadrature LO signals and filtered by the filtering impedance.
    Type: Grant
    Filed: September 16, 2010
    Date of Patent: May 20, 2014
    Assignee: Newport Media, Inc.
    Inventors: Aly Ismail, Edward Youssoufian, Hassan Elwan, Frank Carr
  • Patent number: 8725086
    Abstract: Provided is a high-frequency module that can prevent a transmission signal from reaching a reception circuit and that can achieve high mounting density. A first duplexer for a first frequency band is mounted on a circuit substrate, and a second transmission filter and a second reception filter that constitute a second duplexer for a second frequency band are embedded in the circuit substrate. The second transmission filter and the second reception filter are embedded in the circuit substrate in locations that overlap at least a part of a projection region that is formed by projecting the first duplexer in a thickness direction of the circuit substrate. The first frequency band and the second frequency band are separated from each other by at least a prescribed frequency range.
    Type: Grant
    Filed: October 17, 2013
    Date of Patent: May 13, 2014
    Assignee: Taiyo Yuden Co., Ltd.
    Inventors: Tetsuo Saji, Hiroshi Nakamura
  • Patent number: 8725103
    Abstract: A receiver includes a low noise amplifier having an input for receiving a radio frequency signal, and an output. The receiver further includes a tracking filter having an input coupled to the output of the low noise amplifier. The tracking filter including a bandpass filter configured to pass the radio frequency signals. The bandpass filter includes a variable capacitor having a first electrode coupled to the input of the tracking filter for receiving the radio frequency signals, and a second electrode coupled to a power supply terminal. The bandpass filter further includes a transformer having a primary winding including a first terminal coupled to the first electrode of the variable capacitor and a second terminal coupled to a second power supply terminal. The transformer further includes a secondary winding.
    Type: Grant
    Filed: January 3, 2012
    Date of Patent: May 13, 2014
    Assignee: Silicon Laboratories Inc.
    Inventors: Mustafa H. Koroglu, Yu Su
  • Patent number: 8724686
    Abstract: Certain aspects of the present disclosure relate to a method for equalizing a pulse signal corrupted by a noise and by various channel effects for obtaining a signal based on the periodic-sinc pulse, which is suitable for Finite Rate of Innovation (FRI) processing applied at a receiver of a pulse-based communication system (e.g., an Ultra-Wideband receiver).
    Type: Grant
    Filed: October 13, 2009
    Date of Patent: May 13, 2014
    Assignee: QUALCOMM Incorporated
    Inventor: Yann Barbotin
  • Patent number: 8725506
    Abstract: A speech processing engine is provided that in some embodiments, employs Kalman filtering with a particular speaker's glottal information to clean up an audio speech signal for more efficient automatic speech recognition.
    Type: Grant
    Filed: June 30, 2010
    Date of Patent: May 13, 2014
    Assignee: Intel Corporation
    Inventors: Willem M. Beltman, Matias Zanartu, Arijit Raychowdhury, Anand P. Rangarajan, Michael E. Deisher
  • Patent number: 8725087
    Abstract: Provided is a high-frequency module that can prevent a transmission signal from reaching a reception circuit and that can achieve high mounting density. A first duplexer for a first frequency band is mounted on a circuit substrate, and a second transmission filter and a second reception filter that constitute a second duplexer for a second frequency band are embedded in the circuit substrate. The second transmission filter and the second reception filter are embedded in the circuit substrate in locations that overlap at least a part of a projection region that is formed by projecting the first duplexer in a thickness direction of the circuit substrate. The first frequency band and the second frequency band are separated from each other by at least a prescribed frequency range.
    Type: Grant
    Filed: October 18, 2013
    Date of Patent: May 13, 2014
    Assignee: Taiyo Yuden Co., Ltd.
    Inventors: Tetsuo Saji, Hiroshi Nakamura
  • Publication number: 20140128012
    Abstract: Embodiments of the present invention provide a filter, a receiver, a transmitter, and a transceiver. The filter includes a resonant cavity component, a microstrip filtering component, and two connecting pieces, where the resonant cavity component includes at least two resonant cavities connected in parallel, each resonant cavity is provided with a resonator and a tuning screw, the microstrip filtering component includes a dielectric substrate and a microstrip positioned on the dielectric substrate, one of the connecting pieces matches and connects one end of the microstrip to the resonator on one resonant cavity, the other connecting piece matches and connects the other end of the microstrip to the resonator on another resonant cavity, and impedance of the resonant cavity component is less than impedance of the microstrip filtering component.
    Type: Application
    Filed: September 24, 2013
    Publication date: May 8, 2014
    Applicant: Huawei Technologies Co., Ltd.
    Inventor: Yanzhao Zhou
  • Patent number: 8717212
    Abstract: An improved quadrature bandpass-sampling delta-sigma analog-to-digital demodulator is provided, which includes a loop filter, an A/D responsive to the loop filter, and a first feedback D/A responsive to the A/D up-converted in frequency by a first multiplier and a clock. A first summing circuit is responsive to the first D/A and an RF input for providing an input to the loop filter. A plurality of feedback D/As is responsive to the A/D up-converted in different frequencies by a plurality of multipliers and a plurality of clocks for providing feedback inputs to the loop filter. The loop filter comprises a plurality of resonators arranged in cascade configuration, a plurality of analog mixers to provide frequency shifting of the error signals propagating through the resonators, and a plurality of summing circuits responsive to the feedback D/As.
    Type: Grant
    Filed: September 20, 2012
    Date of Patent: May 6, 2014
    Assignee: Phuong Huynh
    Inventor: Phuong Huynh
  • Publication number: 20140120857
    Abstract: An integrated calibrator provides for magnitude and phase response calibration of RF receivers to produce amplitude flatness and phase linearity across the frequency range of the RF receiver by using a simple square law diode detector and a frequency-stepped two-tone source. A two-tone source generator provides two sinusoidal signals separated by a specified frequency delta about a center frequency. The center frequency is stepped across the bandwidth of the RF receiver. At each center frequency the two sinusoidal signals are input to the RF receiver and to the diode detector. The two sinusoidal signals are processed by both the receiver path and the calibrator path, and the results are used by the calibrator to generate coefficients for a correction filter in the receiver path at each of the stepped center frequencies.
    Type: Application
    Filed: October 26, 2012
    Publication date: May 1, 2014
    Applicant: TEKTRONIX, INC.
    Inventor: TEKTRONIX, INC.
  • Publication number: 20140120858
    Abstract: An object of the present invention is to provide a CRC circuit with more simple structure and low power consumption. The CRC circuit includes a first shift register to a p-th shift register, a first EXOR to a (p?1)th EXOR, and a switching circuit. A data signal, a select signal, and an output of a last stage of the p-th shift register are inputted to the switching circuit, and the switching circuit switches a first signal or a second signal in response to the select signal to be outputted.
    Type: Application
    Filed: January 6, 2014
    Publication date: May 1, 2014
    Applicant: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Masafumi ITO, Tomoaki Atsumi
  • Patent number: 8711993
    Abstract: A wideband multi-channel receiver comprises an antenna configured to receive a radio frequency band comprising an aviation VHF communication band, an aviation VHF navigation band, an aviation L-band, or combinations thereof. A band-pass filter is in signal communication with the antenna, and a low-noise amplifier is in signal communication with the band-pass filter. A mixer is in signal communication with the low-noise amplifier and is configured to translate a radio frequency band to an intermediate frequency (IF) band. A tunable local oscillator is in signal communication with the mixer. At least one fixed-frequency notch filter is in signal communication with the mixer, with the notch filter configured to reject at least one interference signal in the IF band while passing remaining signals in the IF band. An analog-to-digital converter is in signal communication with the notch filter and is configured to convert the remaining signals in the IF band to digital signals.
    Type: Grant
    Filed: December 10, 2010
    Date of Patent: April 29, 2014
    Assignee: Honeywell International Inc.
    Inventors: Alfonso Malaga, Timothy P. Gibson, Jeffrey K. Hunter, Gregory Triplett
  • Publication number: 20140113580
    Abstract: In a splitter, a first band pass filter is connected between an antenna terminal and a first terminal, a high pass filter and a second band pass filter are connected between the antenna terminal and a second terminal, a pass band of the second band pass filter is higher than a pass band of the first band pass filter, a cut off frequency of the high pass filter is located closer to the high-frequency side than the pass band of the first band pass filter, the pass band of the second band pass filter is located closer to the high-frequency side than the cut off frequency, and the high pass filter also functions as a notch filter having an anti-resonant frequency in a transition region such that the steepness of the transition region between the pass band of the second band pass filter and the attenuated band is high.
    Type: Application
    Filed: December 20, 2013
    Publication date: April 24, 2014
    Applicant: MURATA MANUFACTURING CO., LTD.
    Inventor: Sunao YAMAZAKI
  • Patent number: 8706056
    Abstract: Provided is a high-frequency module that can prevent a transmission signal from reaching a reception circuit and that can achieve high mounting density. A first duplexer for a first frequency band is mounted on a circuit substrate, and a second transmission filter and a second reception filter that constitute a second duplexer for a second frequency band are embedded in the circuit substrate. The second transmission filter and the second reception filter are embedded in the circuit substrate in locations that overlap at least a part of a projection region that is formed by projecting the first duplexer in a thickness direction of the circuit substrate. The first frequency band and the second frequency band are separated from each other by at least a prescribed frequency range.
    Type: Grant
    Filed: October 17, 2013
    Date of Patent: April 22, 2014
    Assignee: Taiyo Yuden Co., Ltd.
    Inventors: Tetsuo Saji, Hiroshi Nakamura
  • Publication number: 20140106698
    Abstract: A variable filter device has: a first series arm which is serially connected to a signal line, includes a variable capacitance and an inductance, and constitutes a series resonator; first and second parallel arms, which are connected between the signal line and the ground on both sides of the first series arm, each of which includes a variable capacitance and an inductance, and constitutes a grounded series resonator. The first series arm defines the center frequency of the pass band, and the first and second parallel arms define attenuation poles sandwiching the pass band.
    Type: Application
    Filed: December 18, 2013
    Publication date: April 17, 2014
    Applicant: FUJITSU LIMITED
    Inventors: Xiaoyu Mi, OSAMU TOYODA, Satoshi UEDA
  • Publication number: 20140106697
    Abstract: An interference wave signal removing device that can surely remove an interference wave signal is provided. An interference wave signal remover includes a controller, a notch filter, an entire-range frequency scanner, and a local frequency scanner. The controller detects the interference wave signal based on a frequency scanning result by the entire-range frequency scanner, and sets the notch filter to attenuate the interference wave signal frequency. Based on input signals to the notch filter, the local frequency scanner frequency-scans in a local frequency band including an attenuation band of the notch filter. The controller detects a frequency drift of the interference wave signal frequency based on the frequency scanning result by the local frequency scanner, and updates the setting of the notch filter to attenuate the interference wave signal frequency after the frequency drift.
    Type: Application
    Filed: December 19, 2011
    Publication date: April 17, 2014
    Applicant: FURUNO ELECTRIC CO., LTD.
    Inventors: Dun Wang, Hitoshi Kondo
  • Patent number: 8694037
    Abstract: Method for optimizing the delay spread performance of a radio receiver (200) includes evaluating (306) a delay spread environment to determine if a desired RF signal is being received under conditions of low delay spread or high delay spread. If a low delay spread condition, the baseband digital data signal is filtered using a narrow filter (310). Otherwise, the signal is filtered using a wide bandwidth filter (312) having a bandwidth wider than the narrow filter. The center frequency of the wide bandwidth filter is selectively shifted (316, 320) in accordance with a predetermined frequency offset if a second received power level of an interfering signal in an adjacent channel exceeds the first received power level by a predetermined threshold amount. This frequency shift of the filter allows for improved delay spread performance while minimizing any performance degradation when an interfering signal is present on an adjacent channel.
    Type: Grant
    Filed: February 7, 2013
    Date of Patent: April 8, 2014
    Assignee: Harris Corporation
    Inventor: Mac L. Hartless
  • Patent number: 8688155
    Abstract: What is described is a circuit arrangement and a method for synchronizing the communication signals between a repeater station (S) of a single-frequency simulcast radio communication network (N) and user terminals (T) with respect to a universal reference signal sent by a central station (M) of the network (N) communicating with the repeater station (S). A frequency offset is determined between a universal frequency reference signal received from the central station (M) and a local frequency reference signal of the repeater station (S), and in the repeater station (S) there are provided a first feedback control loop for supplying a signal for controlling a local oscillator of the repeater station (S) on the basis of the said determined frequency offset, and a second direct control loop for supplying a signal for compensating the residual synchronization difference of the local oscillator (16) to which the transmitter device of the station (S) is tuned.
    Type: Grant
    Filed: March 12, 2008
    Date of Patent: April 1, 2014
    Assignee: Selex Communications S.p.A.
    Inventor: Francesco Residori
  • Publication number: 20140087679
    Abstract: A wireless communication device includes a demodulation unit which demodulates a predetermined reception frequency, an S/N improvement processing unit which performs an S/N improvement process on a demodulated signal output from the demodulation unit, a first filter which performs an adaptive operation with respect to a frequency having a largest amplitude in a signal output from the S/N improvement processing unit, and outputs a filter coefficient updated by the adaptive operation, a controller which calculates the frequency of the largest amplitude defined by the filter coefficient output from the first filter, and controls the demodulation unit to update the reception frequency so as to reduce a difference between the frequency having the largest amplitude and a predetermined frequency, and a second filter which limits a range of a frequency bandwidth of the demodulated signal based on the frequency having the largest amplitude.
    Type: Application
    Filed: July 16, 2013
    Publication date: March 27, 2014
    Inventor: Yasunori SUZUKI
  • Patent number: 8681850
    Abstract: A signal processing apparatus includes a signal processing unit configured to carry out signal processing on a single-carrier signal and a multi-carrier signal by making use of a plurality of common filters shared by the single-carrier signal and the multi-carrier signal.
    Type: Grant
    Filed: September 19, 2011
    Date of Patent: March 25, 2014
    Assignee: Sony Corporation
    Inventors: Hidetoshi Kawauchi, Naoki Yoshimochi, Kazukuni Takanohashi
  • Publication number: 20140080436
    Abstract: A novel and useful reconfigurable superheterodyne receiver that employs a 3rd order complex IQ charge-sharing band-pass filter (BPF) for image rejection and 1st order feedback based RF BPF for channel selection filtering. The operating RF input frequency of the receiver is 500 MHz to 1.2 GHz with varying high IF range of 33 to 80 MHz. The gain stages are inverter based gm stages and the total gain of the receiver is 35 dB and in-band IIP3 at mid gain is +10 dBm. The NF of the receiver is 6.7 dB which is acceptable for the receiver without an LNA. The architecture is highly reconfigurable and follows the technology scaling.
    Type: Application
    Filed: September 16, 2013
    Publication date: March 20, 2014
    Applicant: Technische Universiteit Delft
    Inventors: Iman Madadi, Massoud Tohidian, Robert Bogdan Staszewski
  • Publication number: 20140080432
    Abstract: An electronic device includes an adjustable filter with a first filter element, and a second filter element coupled to the first filter element. The second filter element includes a field effect transistor (FET) including a source terminal, a drain terminal, and a gate terminal. The source terminal and the gate terminal are coupled to a reference voltage. A control circuit is coupled to the drain terminal and is configured to apply a control voltage thereto to vary a capacitance between the source and drain terminals to adjust the adjustable filter.
    Type: Application
    Filed: November 19, 2013
    Publication date: March 20, 2014
    Inventors: ANDREW MUI, ANTHONY C. MANICONE
  • Patent number: 8676523
    Abstract: A method of detecting the position of a wavefront in a time-varying signal corresponding to an event is disclosed. According to one aspect, the method includes digitizing a signal received by a detector to produce a working signal, filtering the working signal N4 times with a band-pass filter to obtain N4 filtered working signals with different pass-bands, detecting a peak of the N4 filtered working signals to detect the position of a first wavefront as a function of time of occurrence. The N4 points are plotted such that an ordinate is one of the times of occurrence and an abscissa is the width of the associated band. An exponential asymptote that fits a maximum number of the N4 points is applied, and the position of the wavefront is determined as the ordinate of the point that has the maximum abscissa and substantially fits the exponential asymptote.
    Type: Grant
    Filed: October 18, 2010
    Date of Patent: March 18, 2014
    Assignee: Alstom Technology Ltd.
    Inventor: Raphaël Lebreton
  • Patent number: 8676144
    Abstract: Interference in an unlicensed frequency band is spatially filtered out from received signals at a wireless device operating in the unlicensed frequency band. Energy received at a plurality of antennas of the wireless is device is analyzed to detect interference in the unlicensed frequency band. The detected interference is classified by type. Parameters for a nulling filter are generated or selected based on the type of interference detected in the received energy. During a time interval when it is expected to receive desired signals, the nulling filter is applied using the parameters to signals obtained from energy received at the plurality of antennas during the time interval.
    Type: Grant
    Filed: April 14, 2011
    Date of Patent: March 18, 2014
    Assignee: Cisco Technology, Inc.
    Inventors: Li Guo, Hang Jin, Paul J. Stager, Neil R. Diener, Matthew A. Silverman, Chandra Vaidyanathan
  • Publication number: 20140070989
    Abstract: An interference wave signal frequency is highly accurate and the interference wave signal is surely removed. A controller of an interference wave signal remover detects the interference wave signal based on a frequency scanning result by an entire-range frequency scanner, and sets a notch filter to attenuate the interference wave signal frequency. A local scan frequency band BWfL of a local frequency scanner is set by having the interference wave signal frequency as its central frequency, and local scan frequencies BINL are set so that frequency bands overlap with each other between adjacent frequency BINA. The local frequency scanner frequency-scans input signals to the notch filter. The controller calculates a frequency error ?f of the interference wave signal frequency from the local frequency scanner, corrects the interference wave signal frequency which is from the entire-range frequency scanner by the frequency error ?f, and updates the setting of the notch filter.
    Type: Application
    Filed: December 19, 2011
    Publication date: March 13, 2014
    Applicant: FURUNO ELECTRIC CO., LTD.
    Inventors: Dun Wang, Hitoshi Kondo
  • Publication number: 20140073281
    Abstract: A preselect circuit maintains the dynamic range of a received RF input signal during bandpass filtering of the received RF input signal. The preselect circuit includes a Q-deficient passive bandpass filter for coupling to an antenna to receive a received RF input signal. The preselect circuit further includes a Q-enhancement circuit coupled to the Q-deficient passive bandpass filter, wherein the Q-enhancement circuit increases a Q-value of the Q-deficient passive bandpass filter by compensating for resistive inductive losses in the bandpass filter.
    Type: Application
    Filed: November 12, 2013
    Publication date: March 13, 2014
    Applicant: QUALCOMM Incorporated
    Inventors: Bruce A. Judson, Cong T. Nguyen
  • Publication number: 20140073280
    Abstract: A system for cancellation of a reciprocal-mixing noise may comprise a down-converter mixer that may be configured to down convert a radio-frequency (RF) signal and to generate a baseband signal. The RF signal may include a desired signal and a blocker signal. A first signal path may be configured to receive the baseband signal and to generate a first signal. A second signal path may be configured to receive the baseband signal and to generate a second signal. A subtraction module may be configured to subtract the second signal from the first signal and to generate an output signal. The second signal may comprise the reciprocal-mixing noise, and the output signal may comprise the desired signal substantially free from the reciprocal-mixing noise.
    Type: Application
    Filed: February 15, 2013
    Publication date: March 13, 2014
    Applicant: BROADCOM CORPORATION
    Inventors: Mohyee MIKHEMAR, David MURPHY, Ahmad MIRZAEI, Hooman DARABI
  • Patent number: 8670739
    Abstract: A high quality factor frequency translated bandpass filter (FTBPF) with harmonic rejection includes multiple transconductance cells configured to convert a received radio frequency (RF) voltage signal into respective RF current signals. Each of the transconductance cells are weighted such that the FTBPF has an effective transconductance of a first magnitude for frequency components of the received RF voltage signal arising from a first harmonic and an effective transconductance of a second magnitude less than the first magnitude for frequency components of the received RF voltage signal arising from harmonics at integer multiples of the first harmonic. The FTBPF also includes multiple frequency conversion cells coupled to the transconductance cells and configured to mix respective ones of the RF current signals with multiple non-overlapping local oscillator signals.
    Type: Grant
    Filed: January 8, 2013
    Date of Patent: March 11, 2014
    Assignee: Broadcom Corporation
    Inventors: David Murphy, Hooman Darabi
  • Patent number: 8670733
    Abstract: A multimode communication device with a shared signal path programmable filter and a method for utilizing a shared signal path programmable filter in a multimode communication device. Various aspects of the present invention comprise a first module adapted to receive a first communication signal (e.g., corresponding to a first communication protocol) and a second module adapted to receive a second communication signal (e.g., corresponding to a second communication protocol). A shared filter, communicatively coupled to the first and second modules, may be adapted to filter the first and/or second communication signals in accordance with a plurality of selectable sets of filter response characteristics (e.g., associated with the first and second communication protocols). A filter control module may be adapted to select a set of filter response characteristics from a plurality of such sets and program the shared filter to filter a communication signal in accordance with the selected set.
    Type: Grant
    Filed: January 23, 2012
    Date of Patent: March 11, 2014
    Assignee: Broadcom Corporation
    Inventors: Arya Behzad, Ahmadreza Rofougaran
  • Patent number: 8666346
    Abstract: An FM receiver is unaware of the modulation level (frequency deviation) of the signal and has to make an estimate of it, or some reasonable time-average of it, and accordingly set the input filter's bandwidth. We calculate modulation by measuring the autocorrelation of the recovered audio signal instead of its peaks, and then applying a peakhold detector. Since FM noise can be modeled to be somewhat uncorrelated, we can expect to get an accurate estimate of signal power while rejecting noise power substantially if we measure a one-sample delayed autocorrelation estimate. Since the above measurement is alike a power measurement, we compute its square root, gain adjust it to obtain a cleaner peak measurement, and then track these clean peaks using a leaky integrator. This gives an estimate of modulation that subdues the effect of the noise.
    Type: Grant
    Filed: August 24, 2012
    Date of Patent: March 4, 2014
    Assignee: Texas Instruments Incorporated
    Inventors: Sira Parasurama Rao, John Elliott Whitecar
  • Patent number: 8666351
    Abstract: A SAW-less receiver includes an FEM interface module, an RF to IF receiver section, and a receiver IF to baseband section. The RF to IF receiver section includes a frequency translated bandpass filter (FTBPF), an LNA, and a mixing section. The FTBPF includes a switching network and baseband impedances. The switching network is operable to frequency translate a baseband filter response to a first RF band frequency response and/or to a second RF frequency band response. The FTBPF filters the inbound RF signal to pass, substantially unattenuated, the first and/or second RF band signal components. The LNA amplifies the first and/or second filtered inbound RF signals and the mixing section mixes the first and/or second amplified inbound RF signals with a corresponding first and/or second local oscillation. The IF to baseband section converts the first and/or second inbound IF signals into first inbound symbol stream(s) and/or second inbound symbol stream(s).
    Type: Grant
    Filed: March 30, 2011
    Date of Patent: March 4, 2014
    Assignee: Broadcom Corporation
    Inventors: Ahmad Mirzaei, Hooman Darabi
  • Patent number: 8666350
    Abstract: A circuit includes, an attenuator responsive to an input signal and a feedback signal, a variable gain low-noise amplifier responsive to the attenuator and to the feedback signal, a tracking filter, a frequency converter, and an RSSI responsive to the variable gain amplifier to generate an output signal to which the feedback signal is responsive. The frequency converter may be a mixer having a single-ended input and a differential output. The circuit may further include an analog baseband block responsive to the mixer to filter out high frequency signals. The tracking tuner performs bandpass filtering operation on the output signals of the variable gain low-noise amplifier.
    Type: Grant
    Filed: November 24, 2010
    Date of Patent: March 4, 2014
    Assignee: MaxLinear, Inc.
    Inventor: Ari Vauhkonen
  • Patent number: 8665038
    Abstract: A filtering circuit with BAW type acoustic resonators having at least a first quadripole and a second quadripole connected in cascade, each quadripole having a branch series with a first acoustic resonator of type BAW and a branch parallel with each branch having an acoustic resonator of type BAW, the first acoustic resonator having a frequency of resonance series approximately equal to the frequency of parallel resonance of the second acoustic resonator, the branch parallel of the first quadripole having a first capacitance connected in series with the second resonator and, in parallel with the capacitance, a first switching transistor to short circuit the capacitance.
    Type: Grant
    Filed: February 13, 2009
    Date of Patent: March 4, 2014
    Assignees: STMicroelectronics S.A., Centre National de la Recherche Scientifique
    Inventors: Didier Belot, Alexandre Augusto Shirakawa, Eric Kerherve, Moustapha El Hassan, Yann Deval
  • Patent number: 8660512
    Abstract: A filter stage for use in a receiver includes a switch with an input coupled to an antenna terminal, a first output and a second output; a first filter of a first type coupled to the first output; and a second filter of a second type different from the first type, coupled to the second output. A receiver includes a filter stage as mentioned above; and a switching unit coupled to the filter stage for controlling a switching state of the switch, to selectively connect the antenna terminal to the second output, depending on a selection signal.
    Type: Grant
    Filed: September 21, 2009
    Date of Patent: February 25, 2014
    Inventors: Bernd Adler, Feridoon Jalili, Mikael Bergholz Knudsen, Michael Wilhelm
  • Publication number: 20140051378
    Abstract: Certain disclosed embodiments pertain to suppressing interference in a wireless communication system. For example, a method of suppressing interference can include receiving one or more first signals including components from a plurality of sub-channels. Each of the first signals can be converted into a respective plurality of first sub-band frequency components. A respective spatial filter can be determined for each frequency sub-band using one or more corresponding first sub-band components for each respective spatial filter. One or more second signals including components from the plurality of sub-channels can be received. Each of the second signals can be converted into a respective plurality of second sub-band frequency components. A corresponding plurality of filtered sub-band components can be generated by applying the respective spatial filters to the corresponding second sub-band components for each of the second signals.
    Type: Application
    Filed: July 12, 2013
    Publication date: February 20, 2014
    Inventors: Babak Daneshrad, Jean-Francois Frigon, Anish Narendra Shah, Weijun Zhu
  • Patent number: 8655272
    Abstract: Example embodiments are disclosed for limiting radio frequency noise created during wireless charging of rechargeable batteries in radio frequency communication devices. In an example embodiment, a power source circuit in a wireless charging device produces a source alternating current. The source alternating current is passed through a radio frequency blocking filter to limit radio frequency noise. The filtered source alternating current is then driven through a transmitting coil in the charging device, which inductively couples with a proximately located receiving coil in a radio frequency communication device. An induced alternating current is passed through a second radio frequency blocking filter in the communication device, which limits radio frequency noise that could otherwise be created by the rectifier and control circuits in the communication device.
    Type: Grant
    Filed: July 7, 2009
    Date of Patent: February 18, 2014
    Assignee: Nokia Corporation
    Inventor: Esa Ilmari Saunamäki
  • Patent number: 8655299
    Abstract: A SAW-less receiver includes an FEM interface module, an RF to IF receiver section, and a receiver IF to baseband section. The RF to IF receiver section includes a frequency translated bandpass filter (FTBPF), an LNA, and a mixing section. The FTBPF includes a switching network and a plurality of baseband impedances. The switching network is operable to couple the plurality of baseband impedances to the FEM interface in accordance with a plurality of phase-offset RF clock signals to RF bandpass filter the inbound RF signal. The LNA amplifies the filtered inbound RF signal and the mixing section mixes the amplified inbound RF signal with a local oscillation to produce an inbound IF signal. The receiver IF to baseband section converts the inbound IF signal into one or more inbound symbol streams.
    Type: Grant
    Filed: March 30, 2011
    Date of Patent: February 18, 2014
    Assignee: Broadcom Corporation
    Inventors: Ahmad Mirzaei, Hooman Darabi
  • Patent number: 8655300
    Abstract: A wireless receiver (110) for UWB or other format, receives a useful signal in a particular band of frequencies in site spite of interference components inside and outside the particular band of frequencies. An interference detector (130, 535, 555) detects the in band interference component in a first range of frequencies to include the particular band of frequencies. The same receiver circuitry (120, 300, 310, 505) is adapted to receive a second range of frequencies to include frequencies adjacent to the particular band, to detect the out of band interference component. The position of a second interfering signal in the second range is used to detect artifacts caused by spectral folding so that the required frequency of a band reject filter can be found.
    Type: Grant
    Filed: May 23, 2011
    Date of Patent: February 18, 2014
    Assignee: ST-Ericsson SA
    Inventors: Ajay Kapoor, Maurice Stassen
  • Patent number: 8654909
    Abstract: According to an embodiment, a semiconductor integrated circuit includes an amplifier, an interference wave suppression unit, a coupler and a filter control circuit. The interference wave suppression unit includes a filter being controlled to be on or off. The filter is configured to suppress an interference wave component of an amplified signal to output the signal as an output signal when the filter is on. The coupler is configured to detect an input signal or the output signal. The filter control circuit controls the filter to be on when a signal level of a detection input signal or a detection output signal detected by the coupler is greater than or equal to a reference value, and controls the filter to be off when the signal level is smaller than the reference value, at arbitrary determination timing in a period of time between a transmission and a reception.
    Type: Grant
    Filed: September 20, 2011
    Date of Patent: February 18, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Mitsuyuki Ashida, Hideaki Majima
  • Patent number: 8654831
    Abstract: A signal detection apparatus detects the frequency of an input signal without using a PLL. The detection apparatus includes a first and a second orthogonalizer, a phase difference calculator and an integrator, to control the variable coefficient a1 of a band-pass filter. Information e[k]=M·sin(?) representing the phase difference ? between the input data x[k] and the output data y[k] is calculated with the first and second orthogonalizers and the phase difference calculator. The sign of e[k] is inverted and a predetermined integral calculation is performed with the integrator, and the calculated integral value is set as the coefficient a1 of the band-pass filter. Every time input data x[k] is input, the coefficient a1 is changed by reducing it when e[k]>0 and increasing it when e[k]<0. Thus, the frequency of the output signal of the band-pass filter is matched to the input signal.
    Type: Grant
    Filed: September 20, 2011
    Date of Patent: February 18, 2014
    Assignee: Daihen Corporation
    Inventor: Toyokazu Kitano
  • Patent number: 8655301
    Abstract: Systems and methods are disclosed for an electronically adjustable signal filter system, which comprises, in some embodiments, a first filter coupled to an antenna coupling network and a second filter, a power amplifier coupled to the first filter, an antenna connected to an antenna coupling network, a pilot tone generator coupled to the first filter, and a first signal source connected to the power amplifier and first filter. In some embodiments, the power amplifier amplifies the first signal, the first filter places a notch into the first signal transmitted to the antenna coupling network, the antenna coupling network combines the first signal and a second signal received from the antenna and transmits a third signal to the second filter.
    Type: Grant
    Filed: June 26, 2013
    Date of Patent: February 18, 2014
    Assignee: BlackBerry Limited
    Inventors: Alain Roussel, Charles W. T. Nicholls
  • Patent number: 8644785
    Abstract: This disclosure relates to low noise amplifiers (LNAs) and more particularly to LNAs integrated on integrated circuit (IC) chips along with radio frequency (RF) amplifiers. In one implementation, an impedance translator is coupled to an amplifier, the impedance translator to cause the amplifier to selectively amplify the one or more components of a received signal.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: February 4, 2014
    Assignee: Intel Mobile Communications GmbH
    Inventors: Rastislav Vazny, Krzysztof Dufrene, Hans Pletzer, Werner Schelmbauer, Harald Pretl
  • Publication number: 20140024329
    Abstract: A front end radio architecture is configured to provide a split band frequency arrangement that includes co-banding. The disclosed split band frequency arrangement combines a medium bandwidth filter with a small bandwidth filter to provide enough bandwidth to pass a relatively large communication band. The medium bandwidth filter has a bandwidth that is large enough to support co-banding of smaller communication bands, while also having a narrow enough bandwidth to realize a relatively steep roll-off that ensures coexistence with adjacent bands that are not co-banded. The bandwidths of the medium bandwidth filter and the small bandwidth filter overlap in bandwidth by an amount that is at least as large as the highest bandwidth signal expected to be received or transmitted. The split band frequency arrangement reduces the number of filters needed in the front end radio architecture by repurposing the small bandwidth filter, and by co-banding the smaller communication bands.
    Type: Application
    Filed: June 19, 2013
    Publication date: January 23, 2014
    Inventor: Nadim Khlat
  • Publication number: 20140018029
    Abstract: Filter coefficients are generated by testing a wireless communication system using single-tone signals. While using the filter coefficients in a filter module, signal imbalance caused by a local oscillator or analog elements in a wireless communication system can be eliminated, so as to prevent the wireless communication system from being affected by the noises.
    Type: Application
    Filed: July 8, 2013
    Publication date: January 16, 2014
    Inventors: Yuan-Shuo Chang, Wen-Shan Wang
  • Patent number: 8630603
    Abstract: A circuit and method for image frequency rejection is provided that includes an analog dual-quadrature mixer device whose signal inputs for an in-phase-signal and a quadrature-phase signal are connected to an input circuit in the signal path and whose oscillator inputs for an in-phase oscillator signal and a quadrature-phase oscillator signal are connected to a local oscillator device, having an analog adder-amplifier device, which has a number of transistor pairs, in which in each case both transistors of each transistor pair are connected to the same load resistor for the addition of the signals applied at the control inputs of both transistors, and in which the control inputs of both transistors are connected downstream of the outputs of analog dual-quadrature mixer device, and having a multistage analog polyphase filter whose inputs are connected to outputs of the adder-amplifier device.
    Type: Grant
    Filed: March 3, 2010
    Date of Patent: January 14, 2014
    Assignee: Atmel Corporation
    Inventor: Marco Schwarzmueller
  • Patent number: 8626103
    Abstract: Aspects of the disclosure can provide a second order low pass filter. The second order low pass filter can work in current domain, and have high linearity for in-band signals and out-of-band signals. The second order low pass filter can include a MOS transistor having a gate terminal, a current input terminal and a current output terminal, a first capacitor coupled between the current input terminal and a ground connection and a second capacitor coupled between the gate terminal and the current input terminal.
    Type: Grant
    Filed: February 4, 2013
    Date of Patent: January 7, 2014
    Assignee: Marvell International Ltd.
    Inventors: Fernando De Bernardinis, Rinaldo Castello
  • Publication number: 20140004812
    Abstract: Embodiments include a novel receiver architecture to optimize receiver performance in the presence of interference. In various embodiments, the presence of interference is detected, and the relative frequency location of the interference is detected. The relative frequency location specifies whether the frequency of the interference is high side (above the desired signal, i.e., at a higher frequency) or low side (below the desired signal). The receiver is configured based on the detected interference and relative location thereof. For a device such as a cellular phone that operates in a dynamic and changing environment where interference is variable, embodiments advantageously provide the capability to modify the receiver's operational state depending on the interference.
    Type: Application
    Filed: July 2, 2012
    Publication date: January 2, 2014
    Applicant: Spreadtrum Communications USA Inc.
    Inventors: David Haub, Zhigang Xu, Jarrett Malone