Differential Amplifier Patents (Class 375/318)
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Patent number: 8300733Abstract: Methods and apparatus for reducing sensitivity to nonlinearities in the receiver of a digital communications system are disclosed. One aspect can be referred to as a Post-Distortion Decision Feedback Equalizer (PDFE). A gain stage is often implemented as a variable gain amplifier (VGA), and can introduce significant nonlinearities, a problem exacerbated by signals with a large peak-to-average ratio (PAR). One embodiment provides feed forward information from the VGA regarding its status to a DFE, and the DFE adjusts its filtering based on the provided information. The advantages are also applicable to fixed-gain amplifiers and to transversal filters.Type: GrantFiled: January 5, 2011Date of Patent: October 30, 2012Assignee: PMC-Sierra, Inc.Inventors: Matthew W. McAdam, Anthony Eugene Zortea
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Patent number: 8295408Abstract: A differential amplifier stage under a band design whereby a data signal at a maximum transfer rate among received waveforms is subjected to attenuation upon passing through a transmission line is not amplified, and a signal at a transfer rate half the maximum transfer rate is amplified. If it is determined that a signal whose amplitude is larger in value than a high reference voltage, the signal is determined as a signal “1” while if smaller in value than a low reference voltage, the signal is determined as a signal “0”. If the first amplitude detector detects that the amplitude of the signal is smaller in value than the high reference voltage, and the second amplitude detector detects that the amplitude of the signal is larger in value than the low reference voltage, the present signal is determined as an inverting signal of an immediately preceding signal.Type: GrantFiled: December 29, 2009Date of Patent: October 23, 2012Assignee: Hitachi, Ltd.Inventors: Yuji Ushio, Takashi Muto
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Patent number: 8284860Abstract: Apparatus, systems, and methods are provided for controlling the output of a transmitter using a digital error signal. A method comprises generating a digital reference signal based on a baseband input signal and converting the digital reference signal to an analog reference signal. The method further comprises generating an analog error signal in response to a difference between the analog reference signal and an analog output signal. The method further comprises generating a digital error signal from the analog error signal, and generating an input signal for the transmitter based on the baseband input signal and the digital error signal.Type: GrantFiled: October 31, 2008Date of Patent: October 9, 2012Assignee: Freescale Semiconductors, Inc.Inventors: Bing Xu, Daniel B. Schwartz, Clive K. Tang
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Patent number: 8279747Abstract: There is provided an information processing apparatus includes, an encoding section for encoding a bit string to generate a data signal having an amplitude of a1 and a transmission speed of b; a signal generation section for synchronously adding a clock having a frequency of b/K (K is a predetermined natural number), an amplitude of a2 (>a1), and a small duty ratio to the data signal generated by the encoding section to generate a transmission signal; and a signal transmission section for transmitting the transmission signal generated by the signal generation section.Type: GrantFiled: October 29, 2009Date of Patent: October 2, 2012Assignee: Sony CorporationInventor: Kunio Fukuda
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Patent number: 8265199Abstract: A receiving circuit includes a positive-side level judgment circuit, a negative-side level judgment circuit, and a gate circuit, and is configured to receive input of an AMI-coded signal, convert the signal to a binary output signal, and output the same. The positive-side level judgment circuit judges whether the voltage of an input signal is greater or less than a threshold on the positive side. The threshold on the positive side is provided with a hysteresis characteristic by a positive feedback. The negative-side level judgment circuit judges whether the voltage of an input signal is greater or less than a threshold on the negative side. The threshold on the negative side is provided with a hysteresis characteristic by a positive feedback loop. The gate circuit logically combines the outputs of the positive-side and negative-side level judgment circuits so as to generate the output signal.Type: GrantFiled: May 28, 2007Date of Patent: September 11, 2012Assignee: Daikin Industries, Ltd.Inventor: Takashi Okano
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Patent number: 8208592Abstract: A receiver and a method for a receiver is disclosed. The receiver comprises a signal processing path for receiving a first signal modulated by a first modulation method and having a first bandwidth and a second signal modulated by a second modulation method and having a second bandwidth. A common gain control function is provided for processing said first and second signals. A common DC offset cancellation is also provided for said first and second signals. In a preferred embodiment the gain control and the DC offset cancellation a provided by a single circuit.Type: GrantFiled: April 5, 2002Date of Patent: June 26, 2012Assignee: Nokia CorporationInventor: Sami Vilhonen
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Patent number: 8149955Abstract: A receiver arrangement includes a single ended multiband feedback amplifier, at least one single ended input, differential output mixer arrangement including a main mixer and a trim mixer, and a mixer feedback loop circuit configured to receive differential output signals generated by the mixer arrangement. The mixer feedback loop circuit generates a feedback signal based on the received differential output signals and provides the feedback signal to the mixer arrangement to minimize DC-offset and second order intermodulation products. The single ended multiband feedback amplifier may include an input stage and a programmable resonance tank circuit connected to the input stage for suppressing downconverted noise from harmonics of the LO-frequency, and a configurable feedback net that shapes the frequency response of a feedback loop including the feedback net based on a band operation of the single ended multiband feedback amplifier.Type: GrantFiled: June 30, 2008Date of Patent: April 3, 2012Assignee: Telefonaktiebolaget L M Ericsson (publ)Inventor: Tobias Tired
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Patent number: 8145155Abstract: A passive mixer include a switching architecture configured to generate differential in-phase (I) and differential quadrature-phase (Q) signals using differential components of the in-phase (I) and quadrature-phase (Q) signals operating on transitions of an approximate 25% duty cycle signal.Type: GrantFiled: June 24, 2008Date of Patent: March 27, 2012Assignee: Mediatek, Inc.Inventors: Rajasekhar Pullela, Mohamed El Said
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Patent number: 8144817Abstract: In a high-precision signal detection apparatus and method for a high-speed receiver, signal detection occurs asynchronously of the incoming data. A comparison clock is generated by an oscillator whose effective capacitance is varied by a second, lower speed oscillator connected to the capacitance. This prevents the asynchronous sampling that occurs in a zero-crossing position in the incoming data from remaining in that position in subsequent sampling cycles, so that a valid signal is not missed by the detector.Type: GrantFiled: May 13, 2011Date of Patent: March 27, 2012Assignee: Marvell International Ltd.Inventors: Jafar Savoj, Pierte Roo
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Patent number: 8144813Abstract: A receiving method according to the present invention adjusts a level of an output voltage signal by switching a gain to be used for converting an inputted current signal to a voltage signal, in a preamplifier. Performing offset compensation on the output voltage signal in an offset compensator, in a post amplifier. Adding a reset signal, whose polarity is made opposite to a polarity of the output voltage signal, to the output voltage signal, in the preamplifier. Detecting the reset signal having added to the output voltage signal, and resetting the offset compensator by use of the detected reset signal, in the post amplifier.Type: GrantFiled: August 2, 2005Date of Patent: March 27, 2012Assignees: Nippon Telegraph and Telephone Corporation, NTT Electronics CorporationInventors: Makoto Nakamura, Yuhki Imai, Masatoshi Tobayashi, Yoshikazu Urabe, Hatsushi Iizuka
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Patent number: 8094752Abstract: Amplifier for an ultra-wideband (UWB) signal receiver having a signal input (15) for receiving an ultra-wideband signal which is sent by a transmitter (1) and which is transmitted in a sequence of transmission channels (Ki) (which each have a particular frequency bandwidth) which has been agreed between the transmitter (1) and the receiver (4); a transistor (18) whose control connection is connected to the signal input (15); a resonant circuit (26, 30, 31) which is connected to the transistor (18) and whose resonant frequency can be set for the purpose of selecting the transmission channel (Ki) in line with the agreed sequence of transmission channels; and having a signal output (29) for outputting the amplified ultra-wideband signal, the signal output being tapped off between the transistor (18) and the resonant circuit.Type: GrantFiled: April 29, 2005Date of Patent: January 10, 2012Assignee: Lantiq Deutschland GmbHInventors: Martin Friedrich, Christian Grewing, Giuseppe Li Puma, Christoph Sandner, Andreas Wiesbauer, Kay Winterberg, Stefan Van Waasen
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Publication number: 20110286495Abstract: A signal receiver having a gain control circuit comprising: detection means configured to form a representation of the excess amplitude during a training period of a signal received by the receiver; a first gain stimulus generator configured to generate a first gain stimulus in dependence on the excess amplitude detected by the detection means during the training period; averaging means configured to estimate the average of the signal received by the receiver during the training period; a second gain stimulus generator configured to generate a second gain stimulus in dependence on the average estimated by the averaging means during the training period; and a gain control signal generator configured to generate a gain control signal for the receiver in dependence on the first gain stimulus and the second gain stimulus.Type: ApplicationFiled: August 27, 2009Publication date: November 24, 2011Applicant: CAMBRIDGE SILICON RADIO LIMITEDInventors: Olivier Bernard Andre Seller, Nicolas Sornin, Damien Richard Smith
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Publication number: 20110268202Abstract: In the transmitter, receiver and interface system capable of selective adoption of a differential current driving scheme and a differential voltage driving scheme, a differential current driving scheme and a differential voltage driving scheme can be selectively adopted in one semiconductor chip depending upon the states of the transmission lines, so that effective data transmission is possible and common parts can be shared, whereby a design time can be shortened and a layout area can be reduced.Type: ApplicationFiled: December 3, 2009Publication date: November 3, 2011Applicant: SILICON WORKS CO., LTDInventors: Ju-Pyo Hong, Jun-Ho Kim, Jung-Hwan Choi
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Publication number: 20110222633Abstract: A circuit for down-converting an RF signal to a baseband signal includes a trans-admittance amplifier adapted to receive the RF signal and generate in response a pair of differential current signals. The circuit further includes a trans-impedance amplifier having at least four mixers and at least four linear amplifiers. The four mixers frequency down-convert the pair of differential current signals to generate four pairs of differential baseband current signals, wherein each pair of the differential baseband current signals has a different phase and is associated with each of the linear amplifiers. Additionally, the circuit includes a summing block that generates an in-phase signal using a first weighted sum of the four different baseband current signals and a quadrature signal using a second weighted sum of the four different baseband current signals. The circuit further includes an analog-to-digital converter for converting the in-phase and quadrature signals to respective digital representations.Type: ApplicationFiled: January 5, 2011Publication date: September 15, 2011Applicant: MaxLinear, Inc.Inventors: Raja Pullela, Yu Su, Wenjian Chen
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Patent number: 8000355Abstract: A video signal and an audio signal are TMDS transmitted from a source device to a sink device. Through a reserved line and a HPD line provided separately from a TMDS transmission line, an Ethernet™ signal is bidirectionally transmitted, and also, a SPDIF signal is transmitted from the sink device to the source device. The Ethernet™ signal bidirectionally transmitted between Ethernet™ transmitter/receiver circuits is differentially transmitted by an amplifier and is received by the amplifier. The SPDIF signal from a SPDIF transmitter circuit is common-mode transmitted from an adder and is received by the adder to be supplied to the SPDIF receiver circuit.Type: GrantFiled: July 27, 2010Date of Patent: August 16, 2011Assignee: Sony CorporationInventors: Gen Ichimura, Hidekazu Kikuchi, Yasuhisa Nakajima
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Publication number: 20110176640Abstract: Disclosed are a sampling circuit and a receiver that have a high level of filter design flexibility and excellent image rejection characteristics. Signals with phases that differ by 90° are sampled using an IQ generating circuit (101) and are weighted by each of multiple parallel-connected discrete-time circuits (102-1-102-n), and the result of addition by an output adding circuit (103) is ultimately output. Alternatively, a configuration in which the multiple parallel-connected discrete-time circuits (102-1-102-n) and the output adding circuit (103) are cascade-connected is adopted, so that frequency characteristics having an attenuation pole to one side can be achieved and excellent image rejection characteristics can be obtained.Type: ApplicationFiled: December 4, 2009Publication date: July 21, 2011Applicant: PANASONIC CORPORATIONInventors: Yohei Morishita, Noriaki Saito, Yoshito Shimizu
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Patent number: 7983347Abstract: In a signal transmitter for a multiple differential transmission system including the signal transmitter, a signal receiver, and a signal transmission path including first to third signal lines, first to third differential driver transmit first to third output signals and inverted first to third output signals from the first to third output signals responsive to first to third bit information signals, the first output signal and the inverted third output signal are combined and transmitted to the first signal line, the second output signal and the inverted first output signal are combined and transmitted to the second signal line, and the third output signal and the inverted third output signal are combined and transmitted to the first signal line. The first to third differential drivers of the signal receiver detect polarities of terminal voltages generated across terminal resistances connected between adjacent signal lines and output bit information signals.Type: GrantFiled: April 25, 2007Date of Patent: July 19, 2011Assignee: Panasonic CorporationInventors: Seiji Hamada, Shin-ichi Tanimoto, Hirotsugu Fusayasu
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Patent number: 7983362Abstract: Receiver architectures and bias circuits for a data processor are provided. A receiver architecture includes a linear receiver having a first input node for a data (DQ) signal, a second input node for a reference voltage, and output nodes for a differential output signal. The linear receiver compares the DQ signal to the reference voltage, and generates the differential output signal in response to the comparison. A sense amplifier is coupled to the linear receiver. The sense amplifier has input nodes connected to the output nodes of the linear receiver, and an output node for a binary output signal having voltage characteristics compatible with the processor. The sense amplifier transforms the differential output signal into the binary output signal. The receiver architecture also includes a programming architecture coupled to the linear receiver to set operating characteristics of the linear receiver.Type: GrantFiled: April 10, 2008Date of Patent: July 19, 2011Assignee: GLOBALFOUNDRIES, Inc.Inventors: Shawn Searles, Grace Chuang, Christopher M. Kurker, Curtis M. Brody
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Patent number: 7978773Abstract: An improved multi-channel receiver for satellite broadcast applications or the like. In an exemplary embodiment, a primary AGC loop controls an analog sub-receiver adapted to simultaneously receive multiple signals. Multiple digital demodulators, coupled to the sub-receiver, demodulate the multiple received signals. Multiple secondary AGC loops, one for each received signal, compensate for variations in demodulated signal strengths caused by the primary AGC loop. A feed-forward AGC compensation technique generates scalar control values for scaling the demodulated signals before the demodulated signals are processed by the secondary AGC loops. This at least partially compensates for gain variations caused by the primary AGC, reducing received signal drop-outs before the secondary AGC loops can compensate for the gain variations.Type: GrantFiled: December 29, 2006Date of Patent: July 12, 2011Assignee: Agere Systems Inc.Inventors: Yhean-Sen Lai, Jie Song, Zhenyu Wang, Jinguo Yu
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Publication number: 20110150142Abstract: A discrete-time receiver includes: a sampling mixer sampling an input signal according to a sampling clock; a discrete-time filter adjusting a decimation rate by using a control signal and filtering the sampled signal by using a filter clock; and a clock generator generating a sampling clock to be supplied to the sampling mixer, and generating the control signal and the filter clock by comparing the frequency of the sampling clock with a pre-set output frequency. Over a broadband input signal, a dynamic range of an output signal can be improved.Type: ApplicationFiled: December 17, 2010Publication date: June 23, 2011Applicant: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTEInventor: Young Jae LEE
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Patent number: 7965795Abstract: A control system having an integrator component that provides an integrator output signal used to control a load, and a method controlling the same includes conditioning the integrator component during a fraction of the period in which it would tend to otherwise wind-up.Type: GrantFiled: November 23, 2005Date of Patent: June 21, 2011Assignee: Performance Controls, Inc.Inventor: Craig R. Weggel
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Patent number: 7965480Abstract: A network device comprises an interface coupling an electronic device to a differential pair of signal lines, and an integrated active common mode suppression and electrostatic discharge protection circuit coupled to the interface in parallel to differential signal lines of the electronic device.Type: GrantFiled: November 5, 2007Date of Patent: June 21, 2011Assignee: Akros Silicon Inc.Inventors: Philip John Crawley, Amit Gattani, Jun Cai
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Patent number: 7949078Abstract: In a high-precision signal detection apparatus and method for a high-speed receiver, signal detection occurs asynchronously of the incoming data. A comparison clock is generated by an oscillator whose effective capacitance is varied by a second, lower speed oscillator connected to the capacitance. This prevents the asynchronous sampling that occurs in a zero-crossing position in the incoming data from remaining in that position in subsequent sampling cycles, so that a valid signal is not missed by the detector.Type: GrantFiled: November 19, 2009Date of Patent: May 24, 2011Assignee: Marvell International Ltd.Inventors: Jafar Savoj, Pierte Roo
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Patent number: 7912151Abstract: Methods and apparatus for reducing sensitivity to nonlinearities in the receiver of a digital communications system are disclosed. One aspect can be referred to as a Post-Distortion Decision Feedback Equalizer (PDFE). A gain stage is often implemented as a variable gain amplifier (VGA), and can introduce significant nonlinearities, a problem exacerbated by signals with a large peak-to-average ratio (PAR). One embodiment provides feed forward information from the VGA regarding its status to a DFE, and the DFE adjusts its filtering based on the provided information. The advantages are also applicable to fixed-gain amplifiers and to transversal filters.Type: GrantFiled: March 20, 2007Date of Patent: March 22, 2011Assignee: PMC-Sierra, Inc.Inventors: Matthew W. McAdam, Anthony Eugene Zortea
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Patent number: 7912429Abstract: An upconverter includes a switching architecture configured to receive an input signal, a first local oscillator (LO) signal, and a second local oscillator (2LO) signal that is at a frequency that is twice a frequency of the local oscillator (LO) signal, wherein the switching architecture is configured to switch the input signal on transitions of the second local oscillator (2LO) signal, and wherein the first local oscillator signal and the second local oscillator signal are combined to form combined LO 2LO switching signals.Type: GrantFiled: June 24, 2008Date of Patent: March 22, 2011Assignee: Mediatek, Inc.Inventors: Utku Seckin, Rajasekhar Pullela, Bipul Agarwal
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Patent number: 7894546Abstract: A power amplifier includes a power amplifier core in which a transmit signal having an amplitude-modulated (AM) component and a phase-modulated (PM) component is passed and amplified, the power amplifier comprising a forward path, and an additional amplification device configured to generate an output that is proportional to an output of the power amplifier core, such that the output of the additional amplification device indirectly controls the output of the power amplifier core.Type: GrantFiled: June 29, 2007Date of Patent: February 22, 2011Assignee: Axiom Microdevices, Inc.Inventors: Rahul Magoon, Roberto Aparicio Joo, Scott D. Kee, Ichiro Aoki
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Patent number: 7873123Abstract: A null detector and its corresponding method are provided. The null detector includes a power detector, a smoother, and an overlapper. The power detector outputs a power level signal according to the power level of a received signal. The smoother is coupled to the power detector for determining according to the power level signal whether the received signal is transmitting a null symbol, and then the smoother outputs a null detection signal at a first state value or a second state value indicating the result of the determination. The overlapper is coupled to the smoother for providing the duration and position of the null symbols transmitted by the received signal according to the null detection signal.Type: GrantFiled: July 30, 2007Date of Patent: January 18, 2011Assignee: Alpha Imaging Technology Corp.Inventors: Chih-Chia Wang, Shu-Mei Li, Chingwo Ma, Cen-Chieh Huang
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Patent number: 7864889Abstract: A method and system of establishing an offset for a receiver. In one embodiment, a method includes receiving an input signal and generating a first signal. The method can further include integrating the input signal and the first signal at a reference node. In addition, the method can include comparing the input signal to a signal at the reference node and generating an output signal, analyzing the output signal to determine whether the output signal contains noise, and modifying the first signal based on the analysis of the output signal.Type: GrantFiled: June 15, 2005Date of Patent: January 4, 2011Assignee: Robert Bosch GmbHInventor: Ernest Edmond Pacsai
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Patent number: 7864890Abstract: A signal processing apparatus has a plurality of baseline wander correcting units, provided in a processing path in which a predetermined processing is performed on an input signal. At least one of the plurality of baseline wander correcting units includes a correction permission control unit that controls permission or rejection of correction, and baseline wander in the input signal is corrected sequentially by each of the plurality of baseline wander correcting units, based on a control of the correction permission control unit. The baseline wander correcting unit corrects the baseline wander by determining whether or not the baseline correction is to be effected or not, so that the wander of baseline can be efficiently corrected.Type: GrantFiled: September 21, 2006Date of Patent: January 4, 2011Assignee: Rohm Co., Ltd.Inventors: Atsushi Esumi, Kai Li, Hidemichi Mizuno
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Patent number: 7849755Abstract: Disclosed herein is a starter motor clutch. The clutch includes, a shell, a wedgable component support member operably positioned adjacent the shell, and at least one wedgable component positioned between the shell and the wedgable component support member. The at least one wedgable component is displaceable into engagement with the shell to lock the shell into synchronous movement with the wedgable component support member upon initial rotational movement of the wedgable component support member in either direction relative to the shell while allowing asynchronous movement of the shell relative to the wedgable component support member.Type: GrantFiled: July 24, 2007Date of Patent: December 14, 2010Assignee: Remy Technologies, L.L.C.Inventors: Balazs Palfai, David L. Durant, Joel M. Gray, Peter K. Farrar, Wojciech M. Golab, Gus Sumcad
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Patent number: 7830996Abstract: A display apparatus which processes an input image signal to display it thereon having a connector which is connected with an external source, a differential signal receiver which processes a differential signal from the external source, and a differential signal controller which generates a predetermined temporary differential signal using a single ended signal transmitted from the external source and outputs it to the differential signal receiver. Thus, the display apparatus generates a temporary differential signal corresponding to an input single ended signal to process it as a differential signal, and a control method thereof.Type: GrantFiled: July 13, 2006Date of Patent: November 9, 2010Assignee: Samsung Electronics Co., Ltd.Inventor: Kye-won Ryou
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Patent number: 7787526Abstract: An interface circuit for a multi-differential embedded-clock channel for communicating data provides efficient utilization of the bandwidth of the channel. The interface circuit includes at least four first signals, at least four second signals, and a multi-differential amplifier. The multi-differential amplifier is coupled to the first and second signals. The multi-differential amplifier is adapted to generate the second signals by amplifying, for all combinations of two of the first signals, differential transitions between the two of the first signals. Each of a plurality of symbols of the data has a corresponding one of the differential transitions, and the differential transitions are serially communicated through the channel.Type: GrantFiled: July 12, 2005Date of Patent: August 31, 2010Inventor: James Ridenour McGee
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Patent number: 7778351Abstract: A CMOS receiver system having a tunable receiver having a tunable gain and a bandwidth system is provided. The tunable receiver includes means for receiving input signals; and a control circuit controlled by a control signal for tuning at least one of the gain and the bandwidth of the tunable receiver, wherein the control signal is indicative of a data rate of the input signals. Furthermore, a method is provided for tuning a CMOS receiver receiving input signals. The method includes the steps of receiving at least one control signal, and controlling one of gain and bandwidth of the CMOS receiver in accordance with the at least one control signal, wherein the at least one control signal is indicative of a data rate of the received input signals.Type: GrantFiled: April 9, 2002Date of Patent: August 17, 2010Assignee: International Business Machines CorporationInventors: Louis L. Hsu, Li-Kong Wang, Philip J. Murfet
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Patent number: 7769304Abstract: A signal processing apparatus sets a discrimination level most suitably, regardless of whether the apparatus is in the minimum receiving system or the maximum receiving system. The apparatus comprises a light receiving unit converting input signal light to an electric signal, and a level detecting unit for detecting a high level component and a low level component of the electric signal from the light receiving unit, along with peak levels on a high-side and a low-side of the electric signal.Type: GrantFiled: December 27, 2006Date of Patent: August 3, 2010Assignee: Fujitsu LimitedInventors: Hisaya Sakamoto, Toru Yamazaki, Yoshito Anazawa, Hiroshi Kuzukami
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Patent number: 7760819Abstract: In a wireless receiver that receives an electric signal that has undergone digital modulation, a sample-hold circuit converts a wireless modulated signal, which is a continuous time signal, to a discrete time signal, and the frequency band is converted and selected by means of a band-pass filter. A demodulation circuit carries out demodulation based on the instantaneous value of the voltage amplitude of the modulated signal. A shut-down circuit further effects adaptive control of the circuit shut-down time to minimize the circuit activation time while ensuring that the demodulation error rate of the demodulated baseband signal satisfies a value stipulated by the communication standard.Type: GrantFiled: October 27, 2005Date of Patent: July 20, 2010Assignee: NEC CorporationInventors: Haruya Ishizaki, Masayuki Mizuno
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Patent number: 7729453Abstract: Systems and methods for determining a slicing level which is used as a threshold to determine whether timeslots of an incoming data signal contain ones or zeros. The method of one embodiment comprises receiving a data signal, identifying a maximum level of the data signal, identifying a minimum level of the data signal, determining an average of the minimum and maximum levels, and then using the average of the minimum and maximum levels as a slicing level to identify bits of a data packet embodied in the data signal.Type: GrantFiled: April 25, 2003Date of Patent: June 1, 2010Inventors: Bing Li, David Wolf, James Plesa, Lakshman S. Tamil
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Patent number: 7676152Abstract: In an optical telecommunication system in which an intensity of an arriving optical signal is different for each packet, detected is an optical intensity for each packet with little error. For this purpose, contrived is to detect an average optical intensity across header parts for each packet by focusing on the fact that the header part comprising the preamble and delimiter of a packet is in a bit pattern which includes approximately the same numbers of “0” and “1”.Type: GrantFiled: September 28, 2006Date of Patent: March 9, 2010Assignee: Fujitsu LimitedInventors: Tetsuji Yamabana, Kazuyuki Mori, Satoshi Ide
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Patent number: 7643583Abstract: In a high-precision signal detection apparatus and method for a high-speed receiver, signal detection occurs asynchronously of the incoming data. A comparison clock is generated by an oscillator whose effective capacitance is varied by a second, lower speed oscillator connected to the capacitance. This prevents the asynchronous sampling that occurs in a zero-crossing position in the incoming data from remaining in that position in subsequent sampling cycles, so that a valid signal is not missed by the detector.Type: GrantFiled: October 7, 2004Date of Patent: January 5, 2010Assignee: Marvell International Ltd.Inventors: Jafar Savoj, Pierte Roo
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Patent number: 7636051Abstract: A statistical value update unit calculates the fluctuation of measurement data. A filtering processing unit extracts a normal white noise component from the fluctuation of the measurement data using an adaptive lattice filter. A statistical test unit determines whether or not the variance of the normal white noise component is out of a predetermined scope in reference distribution. A change decision unit detects a stationary change of the status of a target system based on a detection ratio of an outlier.Type: GrantFiled: May 31, 2006Date of Patent: December 22, 2009Assignee: Fujitsu LimitedInventors: Satoshi Imai, Akiko Yamada, Hitoshi Yamada, Hitoshi Ueno, Koji Nakamichi, Akira Chugo
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Radio frequency (RF) receiver with double loop integrated fast response automatic gain control (AGC)
Patent number: 7593484Abstract: A radio frequency (RF) receiver device comprises a receiver system that receives an analog radio frequency signal and downconverts the analog radio frequency signal to a downconverted analog signal, the receiver system further including a peak signal detector configured to determine a peak signal level of the downconverted analog signal, and an automatic gain control adjustment element configured to determine whether the peak signal level falls within a predetermined range, and configured to generate, in the RF receiver, a gain control signal controlling the gain of at least one analog component based on whether the peak signal level falls within the predetermined range.Type: GrantFiled: September 30, 2005Date of Patent: September 22, 2009Assignee: Skyworks Solutions, Inc.Inventors: Norman J. Beamish, William J. Domino, Morten Damgaard, Bala Ramachandran -
Patent number: 7567628Abstract: A self-biasing slicer includes a self-biased differential transistor pair. As a result of the self-biasing, the slicer may receive input signals without the use of AC coupling. That is, a differential input signal may be fed directly to the inputs of the differential transistor pair. The differential pair circuit may incorporate a self-biased load and a self-biased current source. The slicer also may include a matched output stage with inverters that provide a rail-to-rail output. Here, the inverters may incorporate components that are matched with components of the differential pair.Type: GrantFiled: February 11, 2005Date of Patent: July 28, 2009Assignee: Broadcom CorporationInventor: Hooman Darabi
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Publication number: 20090110117Abstract: An active clamp circuit for electronic components includes two sets of diode connected transistors that are inversely connected in parallel across an output of the component for providing both positive and negative differential conducting paths. The diode connected transistors cooperatively operate to limit a differential output voltage between the positive and negative conducting paths. An emitter follower buffer includes the clamp circuit and is configured to limit RF energy incident to an analog to digital converter (ADC). The emitter follower buffer includes two input transistors having their emitters each connected to at least one diode connected transistor connected to the clamp circuit. A receiver includes the differential amplifier and an analog to digital converter. A method for limiting the energy of analog signals in the receiver includes the step of operating the clamp circuit to limit the analog signals transmitted to the analog to digital converter (ADC).Type: ApplicationFiled: October 31, 2007Publication date: April 30, 2009Inventors: Won Chon, Nick J. Rosik, Harry H. Kim, Gregory D. Surbeck, Gharib Gharibianians, Dean W. Schoettler
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Patent number: 7526256Abstract: An apparatus and method for allowing two different signal paths to be coupled to a multi-tap transformer balun. The multi-tap transformer has a first port, which is coupled to a single antenna, and two or more differential secondary ports. Each port has one or more taps, which are optimized separately for each of the signal paths, allowing each of the two or more signal paths to operate in different frequency bands. Use of the method of the invention can decrease the number of external components and integrated circuit package pins, and reduce the area required for each signal path on an integrated circuit die, a printed circuit board, or the like.Type: GrantFiled: May 25, 2005Date of Patent: April 28, 2009Assignee: Broadcom CorporationInventors: Iqbal Bhatti, Jesus Castaneda, Bojko F. Marholev
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Publication number: 20090103654Abstract: One embodiment relates to a low intermediate frequency (IF) receiver. The low-IF receiver includes an analog front end that is configured to receive a modulated IQ data signal and provide an in-phase signal and a quadrature signal, where the in-phase signal is phase shifted by approximately 90° relative to the quadrature signal. The low-IF receiver further includes a digital processing block, and a single path that provides only one of the in-phase signal and the quadrature signal to the digital processing block. Other receivers and methods are also disclosed.Type: ApplicationFiled: October 23, 2007Publication date: April 23, 2009Inventors: Stefan van Waasen, Christian Grewing, Michael Lewis
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Patent number: 7505532Abstract: A signal transmission system is constructed to transmit data over a signal transmission line without requiring precharging the signal transmission line for every bit, by eliminating the intersymbol interference component introduced by preceding data. The signal transmission line has a plurality of switchable signal transmission lines organized in a branching structure or a hierarchical structure, at least one target unit from which to read data is connected to each of the plurality of signal transmission lines, and a readout circuit including a circuit for eliminating the intersymbol interference component is connected to the signal transmission line, wherein the intersymbol interference component elimination circuit reduces noise introduced when the signal transmission line is switched between the plurality of signal transmission lines, and thereby provides a smooth intersymbol interference component elimination operation when the signal transmission line is switched.Type: GrantFiled: November 28, 2006Date of Patent: March 17, 2009Assignee: Fujitsu LimitedInventors: Miyoshi Saito, Junji Ogawa
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Publication number: 20090060092Abstract: A data receiving apparatus is provided to receive command data encoded by using a combination of high-level periods during which there is radio wave and low-level periods during which there is no radio wave. The data receiving apparatus is provided with a receiving circuit including a differential amplifier circuit receiving the command data through an antenna, and a demodulator outputting a reproduced signal corresponding to the command data in response to an output of the differential amplifier; and an offset adjustment switch circuit judging a logic level of the reproduced signal in the low level periods of the command data while the receiving circuit receives the command data, and generates offset switch signals based on the logic level of the reproduced signal in the low level periods. The differential amplifier circuit includes an offset control section adjusting an offset value of the differential amplifier circuit in response to the offset switch signals.Type: ApplicationFiled: August 27, 2008Publication date: March 5, 2009Inventor: Fujio Higuchi
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Patent number: 7496149Abstract: Methods and apparatus are disclosed for transitioning a receiver from a first state to a second state using an in-band signal over a differential serial data link.Type: GrantFiled: December 11, 2006Date of Patent: February 24, 2009Assignee: Intel CorporationInventor: Zale T. Schoenborn
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Patent number: 7496163Abstract: In a slot format of a received signal, AGC gain update timings (t1 to t4) are shifted every time to disperse and reduce an influence of a noise attributable to a direct current component specific to direct conversion which is accompanied by AGC gain update. In particular, in the case where each of slots in the received signal includes an information portion (data) having a larger code correcting capability and an information portion having a smaller code correcting capability (TPC (transmission power control), TFCI (transport format combination indicator), PILOT), the AGC gain update timing is generated while being shifted in the former information portion, thereby reduce the influence of the noise. When the amount of shift of the AGC gain update timing is set to be larger than that of one symbol of the received signal, the influence of the noise accompanied by the AGC gain update is further reduced.Type: GrantFiled: December 9, 2004Date of Patent: February 24, 2009Assignee: NEC CorporationInventor: Kenji Terao
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Patent number: 7489741Abstract: A method to perform DC compensation on a Radio Frequency (RF) burst transmitted between a servicing base station and a wireless terminal in a cellular wireless communication system that first receives the RF burst modulated according to either a first or second modulation format. Samples from the RF burst, or taken from the training sequence, are produced and averaged to produce a DC offset estimate. The DC offset estimate is then subtracted from each of the samples. The modulation format of RF burst may then be identified from the samples. Depending on the identified modulation format the DC offset estimate may be re-added to the samples when a particular modulation format is identified as the modulation format of the RF burst. This decision is made based on how well various components within the wireless terminal perform DC offset compensation.Type: GrantFiled: March 25, 2006Date of Patent: February 10, 2009Assignee: Broadcom CorporationInventors: Baoguo Yang, Nelson R. Sollenberger
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Patent number: 7477704Abstract: Methods and apparatuses for detecting digital signals in high speed signaling systems. In at least one embodiment, at least one received input signal is combined with a plurality of predetermined reference signals according to a plurality of prior digital signal output states to generate a signal for detecting a present digital signal output state. In one aspect of the invention, a method for determining a digital signal state in a differential signaling system includes: comparing a first differential input signal to a second differential input signal; determining a prior digital signal output state; comparing the first differential input signal to one of a first reference voltage and a second reference voltage; comparing the second differential input signal to one of the first reference voltage and the second reference voltage; and determining a present digital signal output state from the prior digital signal output state and from all of the comparisons.Type: GrantFiled: April 16, 2003Date of Patent: January 13, 2009Assignee: Apple Inc.Inventor: William Cornelius