Forward Acting Patents (Class 455/235.1)
  • Patent number: 8472906
    Abstract: Disclosed herein are systems and methods for recovering a sub-carrier signal from a multiplexed signal having an embedded pilot tone signal. The recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for generating a frequency-doubled signal from the recovered pilot signal, and for phase-shifting the frequency-doubled signal by a pre-determined phase difference from the embedded pilot tone signal. Another recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for phase-shifting the pilot signal by a pre-determined phase difference from the embedded pilot tone signal, and for generating a frequency-doubled signal from the phase-shifted signal.
    Type: Grant
    Filed: August 30, 2012
    Date of Patent: June 25, 2013
    Assignee: Marvell International Ltd.
    Inventors: Chris Cheng-Chieh Lee, Hui-Ling Lou, Jungwon Lee
  • Patent number: 8320865
    Abstract: The present invention relates to a method, an Automatic Gain Control control unit and a receiver for Noise change output signalling. It also relates to an Adjustment Unit, a receiver and a base band detector for adjustment of an Automatic Gain Control output signal on the basis of the Noise change output signalling. In a first step a receiver receives a communication input signal. In a second step at least one Automatic Gain Control attenuator or amplifier in the receiver attenuates the communication input signal. In a third step the receiver produces at least one AGC output signal. In a fourth step at least one AGC control unit in the receiver initiates a changed gain setting on the receiver, when the level of an AGC control unit input signal received by the unit has been below a first threshold level or above a second threshold level during a detection interval.
    Type: Grant
    Filed: May 15, 2008
    Date of Patent: November 27, 2012
    Assignee: Telefonaktiebolaget L M Ericsson (Publ)
    Inventor: Vimar Björk
  • Publication number: 20120258679
    Abstract: An interference signal reducing apparatus of a wireless communication system divides a signal that is input through a receiving antenna into a first signal and a second signal having a magnitude larger than that of the first signal and detects a frequency and a magnitude of an interference signal from the first signal, thereby generating an interference removal signal and then adds an interference removal signal to the signal that is input through the receiving antenna and thus reduces a magnitude of the interference signal.
    Type: Application
    Filed: April 6, 2012
    Publication date: October 11, 2012
    Applicant: Electronics and Telecommunications Research Institute
    Inventor: Dong Pil CHANG
  • Patent number: 8260238
    Abstract: Disclosed herein are systems and methods for recovering a sub-carrier signal from a multiplexed signal having an embedded pilot tone signal. The recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for generating a frequency-doubled signal from the recovered pilot signal, and for phase-shifting the frequency-doubled signal by a pre-determined phase difference from the embedded pilot tone signal. Another recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for phase-shifting the pilot signal by a pre-determined phase difference from the embedded pilot tone signal, and for generating a frequency-doubled signal from the phase-shifted signal.
    Type: Grant
    Filed: January 29, 2010
    Date of Patent: September 4, 2012
    Assignee: Marvell International Ltd.
    Inventors: Chris Cheng-Chieh Lee, Hui-Ling Lou, Jungwon Lee
  • Patent number: 8259878
    Abstract: Provided are apparatus and method for receiving signals in a wireless communication system.
    Type: Grant
    Filed: December 3, 2009
    Date of Patent: September 4, 2012
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Chanho Yoon, Hun-Sik Kang, Eun-Young Choi, Sok-Kyu Lee
  • Patent number: 8055231
    Abstract: Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.
    Type: Grant
    Filed: November 18, 2010
    Date of Patent: November 8, 2011
    Assignee: Texas Instruments Incorporated
    Inventors: Khurram Muhammad, Meng-Chang Lee, Dirk Leipold
  • Patent number: 8041323
    Abstract: A portable electronic unit has a transmission-side section that transmits a signal and a receiving-side section that receives a signal from the transmission-side section. The receiving-side section includes a gain control amplification device that amplifies and outputs a signal from the transmission-side section. The gain control amplification device has a first amplification circuit that amplifies and outputs a signal from the transmission-side section, a detection circuit that detects and outputs a signal from the first amplification circuit, a gain control amplification circuit that amplifies and outputs a signal from the detection circuit, and a gain control circuit that controls a gain in the gain control amplification circuit in response to a level of a signal from the detection circuit.
    Type: Grant
    Filed: July 18, 2006
    Date of Patent: October 18, 2011
    Assignee: Seiko Instruments Inc.
    Inventor: Kazuo Kato
  • Patent number: 7885625
    Abstract: Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.
    Type: Grant
    Filed: March 13, 2007
    Date of Patent: February 8, 2011
    Assignee: Texas Instruments Incorporated
    Inventors: Khurram Muhammad, Meng-Chang Lee, Dirk Leipold
  • Patent number: 7769116
    Abstract: Described herein is a method of automatic gain control and simultaneous digital correction of three types of variations in I/Q receivers: gain imbalance, phase imbalance, and DC offset. Three adaptation loops can operate simultaneously and use the output of an analog to digital converter (ADC) as their input, with the output driving digitally controllable analog components. With appropriate knowledge of signal statistics, the algorithm automatically optimally fills the ADC's full input signal range, providing an automatic gain control function and thus maximizing the signal-to-quantization-noise ratio. In so doing, it corrects gain imbalances between I and Q paths, while additional circuitry corrects DC offsets and phase imbalances.
    Type: Grant
    Filed: November 28, 2006
    Date of Patent: August 3, 2010
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Agustin Lebron, Konstantin A. Kouznetsov, Mehdi Tavassoli Kilani
  • Patent number: 7684774
    Abstract: Disclosed herein are systems and methods for recovering a sub-carrier signal from a multiplexed signal having an embedded pilot tone signal. The recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for generating a frequency-doubled signal from the recovered pilot signal, and for phase-shifting the frequency-doubled signal by a pre-determined phase difference from the embedded pilot tone signal. Another recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for phase-shifting the pilot signal by a pre-determined phase difference from the embedded pilot tone signal, and for generating a frequency-doubled signal from the phase-shifted signal.
    Type: Grant
    Filed: October 17, 2006
    Date of Patent: March 23, 2010
    Assignee: Marvell International Ltd.
    Inventors: Chris Cheng-Chieh Lee, Hui-Ling Lou, Jungwon Lee
  • Patent number: 7680473
    Abstract: A signal gain control circuit. A gain stage receives and amplifies an analog signal by a first gain factor adjusted by a gain adjusting signal in a periodic manner with a first period, and outputs an amplified signal. An analog to digital converter converts the amplified signal to a first digital signal comprising a stream of samples. An amplifying device adjusts a second gain factor in a periodic manner with a second period in accordance with a characteristic metric of the distribution of the first digital signal and multiplying the first digital signal by the second gain factor to generate a second digital signal. A first gain adjusting device detects a strength of the second digital signal and generates the gain adjusting signal according to the signal strength of the second digital signal in a periodic manner with the first period.
    Type: Grant
    Filed: September 19, 2006
    Date of Patent: March 16, 2010
    Assignee: Mediatek Inc.
    Inventor: Ming-Luen Liou
  • Patent number: 7555274
    Abstract: A radio receiver comprises an LNA which amplifies An RF signal, a quadrature demodulator which directly demodulates the amplified RF signal into a B/B signal, using a LO signal, a VGA which amplifies the B/B signal, a DC offset canceller which executes feedback control on the amplified B/B signal, and a gain controller which controls at least the gain of the LNA, the gain controller including a signal intensity detector which detects the intensity of the amplified B/B signal, a gain selector which selects a desired one of preset gains on the basis of the detected intensity, a timing controller which controls timing of switching to the selected desired gain, and a gain control signal generator which changes, in accordance with the controlled timing, the interval at which an LNA gain control signal is generated.
    Type: Grant
    Filed: November 17, 2005
    Date of Patent: June 30, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takehiko Toyoda, Hiroshi Yoshida, Takayuki Kato
  • Patent number: 7515890
    Abstract: A radio receiver comprises an LNA which amplifies An RF signal, a quadrature demodulator which directly demodulates the amplified RF signal into a B/B signal, using a LO signal, a VGA which amplifies the B/B signal, a DC offset canceller which executes feedback control on the amplified B/B signal, and a gain controller which controls at least the gain of the LNA, the gain controller including a signal intensity detector which detects the intensity of the amplified B/B signal, a gain selector which selects a desired one of preset gains on the basis of the detected intensity, a timing controller which controls timing of switching to the selected desired gain, and a gain control signal generator which changes, in accordance with the controlled timing, the interval at which an LNA gain control signal is generated.
    Type: Grant
    Filed: November 17, 2005
    Date of Patent: April 7, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takehiko Toyoda, Hiroshi Yoshida, Takayuki Kato
  • Patent number: 7505824
    Abstract: An audio signal processing apparatus and method in which power supplied to a power amplifier is controlled in a wide range from a small output power level to a large output power level in accordance with input audio signals. The apparatus includes an interface unit configured to convert input audio signals to digital audio signals, a digital signal processor configured to process the digital audio signals converted by the interface unit, a volume unit configured to adjust a volume of the digital audio signal processed by the digital signal processor and generate at least one volume modulated signal, and an amplifier configured to amplify the at least one volume modulated signal, wherein power supplied to the amplifier is based on a level of the digital audio signal converted by the interface unit and the at least one volume modulated signal from the volume unit.
    Type: Grant
    Filed: July 14, 2005
    Date of Patent: March 17, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masaru Ebi, Yasuyuki Suzuki
  • Patent number: 7471658
    Abstract: Systems and techniques are disclosed relating to communications. The systems and techniques involve supporting communications between a base station and a plurality of users by establishing an overhead channel between one of the users and the base station, and transmitting data from said one of the users to the base station on the overhead channel in response to a message having a threshold value related to a loading on the base station by the users. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: December 4, 2002
    Date of Patent: December 30, 2008
    Assignee: QUALCOMM, Incorporated
    Inventors: Sivaramakrishna Veerepalli, Nikolai K. N. Leung
  • Patent number: 7433431
    Abstract: A method of and device for automatic gain control (AGC) incorporates digitally controlled variable gain amplifiers (VGAs). An AGC circuit comprises multiple AGC stages, where each of the stages comprises: respective I and Q VGAs; a detector for detecting respective I and Q output signals received from the respective I and Q VGAs; an analogue to digital converter for converting the detected I and Q output signals; and a digital engine for adjusting the respective I and Q VGAs for differences between the detected I and Q output signals and a reference signal. Using staggered AGCs incorporating respective I and Q VGAs splits the total dynamic range between n stages, allowing for reduced gain requirements in the VGAs. Using digital control for setting the VGA gains reduces analogue variations and I/Q gain imbalances. Using multiple update rates or magnitudes in the VGA control improves dynamic settling time.
    Type: Grant
    Filed: September 12, 2003
    Date of Patent: October 7, 2008
    Assignee: Zarbana Digital Fund, LLC
    Inventor: Neil Birkett
  • Patent number: 7248890
    Abstract: A transceiver according to some embodiments of the present invention receives data from a plurality of frequency separated transmission channels from a complementary transmitter of another transceiver and adjusts the power output of certain channels in a transmitter of the receiver. Upon start-up, the power output levels of signals in individual channels in the transmitter can be preset. A power balance can determine new power output levels of the transmitter from parameters in the receiver while receiving data transmitted by a similarly situated complementary transmitter in a second transceiver coupled to the transceiver. In some embodiments, a complementary receiver of the other transceiver determines the power outputs of the transmitter and the power levels are transmitted to the transmitter by the other transceiver.
    Type: Grant
    Filed: February 6, 2004
    Date of Patent: July 24, 2007
    Assignee: Vativ Technologies, Inc.
    Inventors: Sreen A. Raghavan, Thulasinath G. Manickam, Peter J. Sallaway, Gerard E. Taylor
  • Patent number: 7155187
    Abstract: The present invention improves an inconvenience of the conventional system in that cordless hand sets must be registered in advance, and reduces the power consumption in the waiting state. The digital codeless telephone according to the invention uses a public telephone network. In the system of the invention, a transmitting party calls a receiving party by means of a message having a group identification code for direct communication between personal stations and information for a waiting mode change request. The system makes the receiving party prepare for receiving, by an event that the receiving party changes the waiting mode according to the message.
    Type: Grant
    Filed: December 4, 2003
    Date of Patent: December 26, 2006
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Hideyuki Urita
  • Patent number: 7155185
    Abstract: Apparatus and methods for eliminating DC offset in a wireless communication device operable on a continuous basis or on a sampled basis. In a receive channel, the output of a forward variable gain amplifier is fed back to an RC circuit to charge the capacitor (C) to a voltage dependent on the DC offset in the variable gain amplifier output. The voltage on the capacitor is amplified and summed with the input to the variable gain amplifier. The RC circuit is configured to provide a high gain feedback at DC and very low frequencies, but very low gain at signal frequencies. Preferably the output of the forward variable gain amplifier is fed back to the RC circuit with a gain that is inversely proportional to the forward gain. Disconnection of the capacitor and feedback of the capacitor voltage provides sampled operation. Various embellishments and sample applications are disclosed.
    Type: Grant
    Filed: June 9, 2004
    Date of Patent: December 26, 2006
    Assignee: Theta Microelectronics, Inc.
    Inventor: Spyros Pipilos
  • Patent number: 7149487
    Abstract: In receiver systems for cellular phones using the W-CDMA method, the change in DC voltage occurring when the gain of a programmable gain amplifier (PGA circuit) is switched to adjust the gain for a received signal, can be suppressed. A sample-and-hold circuit is installed containing a “sample” mode for directly outputting a signal from the PGA section and also containing a “hold” mode for outputting the electric charge of a specified voltage stored in a capacitor. This sample-and-hold circuit normally operates in “sample” mode so the output signal from the PGA section is directly output, but is operated in “hold” mode at the gain switching timing of the PGA circuit, so that the electric charge of the specified voltage stored in the capacitor is output for a specified length of time (equal to the time required for the DC voltage change to converge to a stable level).
    Type: Grant
    Filed: December 18, 2003
    Date of Patent: December 12, 2006
    Assignee: Sony Ericsson Mobile Communications Japan, Inc.
    Inventor: Atsushi Yoshizawa
  • Patent number: 6885851
    Abstract: An automatic gain control circuit optimizes a follow-up performance of an automatic gain control loop to thus assure a good receiving operation. A generation timing or a generation period of a control signal GC is decided in response to a lapsed time in operation of the receiver device. For a predetermined rise period from a non-operated state to the steady operation state when a power supply is shifted from its OFF state to its ON state (power supply is turned ON) or at the time of intermittent receiving operation, the generation period of the control signal GC is set shorter than the generation period in a steady operation state so as to accelerate the response characteristic of the automatic gain control gain rather than the steady operation condition, and then switched to the generation period in the steady operation state after a predetermined time.
    Type: Grant
    Filed: March 17, 2000
    Date of Patent: April 26, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Nozomi Miura
  • Patent number: 6885752
    Abstract: A hearing compensation system for the hearing impaired comprises a plurality of bandpass filters having an input connected to an input transducer and each bandpass filter having an output connected to the input of one of a plurality of multiplicative AGC circuits whose outputs are summed together and connected to the input of an output transducer. The multiplicative AGC circuits attenuate acoustic signals having a constant background level without the loss of speech intelligibility. The identification of the background noise portion of the acoustic signal is made by the constancy of the envelope of the input signal in each of the several frequency bands. The background noise that will be suppressed includes multi-talker speech babble, fan noise, feedback whistle, florescent light hum, and white noise.
    Type: Grant
    Filed: November 22, 1999
    Date of Patent: April 26, 2005
    Assignee: Brigham Young University
    Inventors: Douglas Melvin Chabries, Richard Wesley Christiansen, Aaron Michael Hammond, William Charles Borough
  • Patent number: 6859505
    Abstract: A method, apparatus and system for use in determining a pilot-to-data power ratio by receiving a data symbol (122) having a data amplitude, receiving a pilot signal (124) having a pilot amplitude, reverse training (350) an automatic gain (154) based on the data amplitude and the pilot amplitude, and determining a pilot-to-data power ratio (250) according to the reverse training of the automatic gain. In some embodiments the method further compensates for channel fading in the data symbol by providing for channel correction (340) on the data symbol, providing for channel correction (344) on the pilot signal and dividing the channel corrected data symbol by the channel corrected pilot signal providing a fading compensated data symbol, where the fading compensated data symbol (150) is provided prior to reverse training such that the reverse training is based at least in part on the fading compensated data symbol.
    Type: Grant
    Filed: July 1, 2003
    Date of Patent: February 22, 2005
    Assignee: Motorola, Inc.
    Inventors: Gregory Agami, Robert John Corke, George Powley
  • Patent number: 6668172
    Abstract: A reception apparatus and a reception processing method are proposed to improve a reception characteristic by compensating deterioration of transmission quality independently of the traveling speed of a terminal. When a transmission signal sent via a radio transmission path is received and data is demodulated by carrying out various kinds of reception processing on the received signal, the present invention can perform reception processing best suited to a radio transmission path whose state changes according to the traveling speed of the terminal itself by receiving traveling speed information from speed detection means for detecting the traveling speed of the terminal itself and controlling reception processing on the reception signal according to the traveling speed information.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: December 23, 2003
    Assignee: Sony Corporation
    Inventor: Osamu Yoshimura
  • Patent number: 6580905
    Abstract: A system and method are provided for controlling the gain of signals transported over transmission media in a distributed antenna network. The system includes a plurality of remote antenna units where each remote antenna unit includes a signal level comparator for comparing the level of the signals received by the respective antenna unit with a predetermined reference level, and a gain controller for reducing the gain of the remote antenna unit when the signal level comparator determines that the level of the received signal exceeds said predetermined reference level. The system may accommodate TDMA systems when a gain controller is used that is fast enough to respond within the time slots of the received signals. As a result, the signal levels output from the remote antenna units are prevented from exceeding a maximum signal level.
    Type: Grant
    Filed: July 2, 1996
    Date of Patent: June 17, 2003
    Assignee: Ericsson Inc.
    Inventors: Arun Naidu, Steven Morelen
  • Publication number: 20030036361
    Abstract: In a method and an apparatus of transmitting a burst signal when the burst signal is transmitted from a transmitting station to a receiving station at a transmission power value and/or a transmission rate determined in accordance with a state of a radio channel between the transmitting and receiving station in a mobile communication system, based on a comparison result between a criterion predetermined according to a state of the radio channel and/or a transmission waiting state of the signal, whether or not the burst signal is to be transmitted is determined, and, when it is determined that the burst signal is to be transmitted, the burst signal is transmitted from the transmitting station to the receiving station.
    Type: Application
    Filed: December 12, 2001
    Publication date: February 20, 2003
    Inventors: Hiroyuki Kawai, Hirohito Suda, Yasushi Yamao
  • Publication number: 20020093933
    Abstract: A method for operating a user equipment employing a CDMA technique comprises combining a plurality of spread spectrum data signals into a combined signal having a fluctuating power level corresponding to the data signals; modulating the combined signal to produce an RF signal; measuring average power of the combined signal over a selected time period; adaptively limiting the combined signal power to a calculated level based at least in part on the measured power; and transmitting the RF signal.
    Type: Application
    Filed: March 4, 2002
    Publication date: July 18, 2002
    Applicant: InterDigital Technology Corporation
    Inventors: Fatih M. Ozluturk, Brian Kiernan
  • Patent number: 6285863
    Abstract: A system and method for providing automatic gain control (AGC) with high dynamic range. An AGC system comprises an open loop control system and a closed loop control system. The open control loop system senses the power level of an input signal and preprocesses the input signal based on its sensed power level. For instance, a strong input signal is attenuated by a fixed level via an analog attenuator, a weak input signal is amplified by a fixed factor via a low noise amplifier, and an intermediate level input signal is directly passed to the closed loop control system of the AGC without any attenuation or amplification. By preprocessing the input signal, the closed loop control system can operate in a range that is optimal for its performance. For instance, a gain variable amplifier of the closed loop control circuit can be prevented from operating in a high attenuation status where its noise figure is very high. A wide band receiver using the AGC system may have a dynamic range over 100 dB.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: September 4, 2001
    Assignee: Lucent Technologies Inc.
    Inventor: Zexiang Zhang
  • Patent number: 6169619
    Abstract: An optical signal receiving apparatus capable of substantially instantaneously and stably discriminating the logic from the header of a burst-like optical signal comprising a pre-amplifier circuit for amplifying an output from a photodiode receiving cell signals, a dummy side variable gain amplifying unit for performing the gain control by feedback control with respect to the output from the pre-amplifier circuit and outputting the gain at that time as gain information, a memory unit for holding the gain information, and a signal side variable gain amplifying unit for performing the gain control by feedfoward control by using the gain set by the gain information and outputting the amplified signal.
    Type: Grant
    Filed: April 2, 1998
    Date of Patent: January 2, 2001
    Assignee: Fujitsu Limited
    Inventor: Satoshi Ide