Phase Locking Patents (Class 375/373)
  • Patent number: 8373461
    Abstract: A VCO oscillates at a frequency that corresponds to a control voltage. A frequency mixer performs frequency mixing of the output signal of the VCO and a local signal having a local frequency. A first filter extracts a difference frequency signal obtained by the mixing operation of the mixer. A phase difference detection unit makes a comparison between the phase of the difference frequency signal extracted by the first filter and the phase of a reference signal having a reference frequency, and generates a phase difference signal that corresponds to the phase difference. A loop filter performs filtering of the phase difference signal so as to generate the control signal. A second filter extracts a summation frequency signal obtained by the mixing operation of the mixer, and outputs the summation frequency signal via an output terminal thereof.
    Type: Grant
    Filed: May 10, 2011
    Date of Patent: February 12, 2013
    Assignee: Advantest Corporation
    Inventor: Hideyuki Okabe
  • Patent number: 8373456
    Abstract: The domain crossing circuit of a semiconductor memory apparatus for improving a timing margin includes a sampler that provides a sampling internal signal generated by delaying an internal input signal by a predetermined time in response to a clock and an edge information signal that defines an output timing of the sampling internal signal and an output stage that allows the sampling internal signal to be synchronized with the clock in response to the edge information signal to be output as a final output signal.
    Type: Grant
    Filed: June 17, 2009
    Date of Patent: February 12, 2013
    Assignee: Hynix Semiconductor Inc.
    Inventors: Hae Rang Choi, Yong Ju Kim, Sung Woo Han, Hee Woong Song, Ic Su Oh, Hyung Soo Kim, Tae Jin Hwang, Ji Wang Lee, Jae Min Jang, Chang Kun Park
  • Patent number: 8369452
    Abstract: Apparatus, methods, and systems are disclosed, including, for example, a data receiver to receive a calibration voltage and a reference voltage to calibrate the data receiver. The output of the data receiver is provided to a first ripple counter that counts the outputs from the data receiver and provides an output count. The ripple counter may count either ones or zeros. A second ripple counter counts the number of a clock signals over the same period of time. The output count is either multiplied by two or the count of clock signals is divided by two. A ripple comparator may then compare the outputs and adjust the reference voltage based upon the comparison results.
    Type: Grant
    Filed: December 7, 2007
    Date of Patent: February 5, 2013
    Assignee: Micron Technology, Inc.
    Inventor: Dragos Dimitriu
  • Patent number: 8358728
    Abstract: Arbitrary phase variations of a shared frequency synthesizer can be calibrated using a reference harmonic each time the shared frequency synthesizer is allocated to a network device to enable one frequency synthesizer to be shared between multiple network devices. On determining that the shared frequency synthesizer has been allocated to the network device, an output frequency of the shared frequency synthesizer can be aligned with a predetermined reference frequency that is associated with an operating frequency band of the network device. A phase correction factor associated with the shared frequency synthesizer can be calculated from a signal calculated based, at least in part, on the output frequency of the shared frequency synthesizer and the predetermined reference frequency. The phase correction factor is applied to a signal received at the network device to correct a phase error associated with the shared frequency synthesizer.
    Type: Grant
    Filed: January 7, 2011
    Date of Patent: January 22, 2013
    Assignee: QUALCOMM Incorporated
    Inventor: Paul J. Husted
  • Patent number: 8355478
    Abstract: Method and system for aligning a clock signal to parallel data are described. According to one embodiment, a clock shifting circuit shifts an incoming clock signal relative to an incoming data signal, and a data clocking circuit uses the shifted clock signal to reclock the incoming data signal. The clock shifting circuit may comprise a phase locked loop (PLL) coupled with multiple D flip flops (DFFs) connected in series. Divisional combinatorial logic may be disposed between DFFs in the series. Data clocking circuits may comprise one DFF to reclock each incoming data bit, a pair of DFFs to reclock each incoming data bit, or other circuits such as true-complement blocks to serve as local oscillators to mixers. Multiple shifted clock signals may be produced, such as those shifted 60, 90, 120, 180, 240, and 270 degrees relative to the incoming clock signal.
    Type: Grant
    Filed: May 29, 2009
    Date of Patent: January 15, 2013
    Assignee: Honeywell International Inc.
    Inventors: James Douglas Seefeldt, Weston Roper, James Hansen
  • Patent number: 8351558
    Abstract: The disclosure provides an effective means for fine-resolution determination of the frequency content of an RF signal using low speed digital circuits. The disclosure relates to a method and apparatus for decomposing a high frequency RF signal into several low frequency signals or data streams without loss of any information and without the use of extraneous circuit components such as local oscillators, mixers or offset phase-locked loops. Single or multiple phase oscillator outputs are fed directly to a single or multiple direct RF frequency-to-digital (DrfDC) circuits. The front end of the DrfDC circuit decomposes a high frequency signal into several low frequency signals without loss of any information. The low frequency signals are processed by the back-end of the DrfDC and converted into digital data streams. The digital data streams are then combined and averaged to represent the frequency of the input RF signal.
    Type: Grant
    Filed: September 25, 2009
    Date of Patent: January 8, 2013
    Assignee: Panasonic Corporation
    Inventors: Richard H. Strandberg, Paul Cheng-Po Liang
  • Publication number: 20130003907
    Abstract: One embodiment of the present invention relates to a phase alignment system including a plurality of samplers, a clock distributor, a phase detector and a phase alignment control. The samplers are configured to receive an incoming signal and a phase adjusted clock signal and to provide samples according to the incoming signal. The clock distributor receives a clock adjustment signal and generates the phase adjusted clock signal, which triggers sampling of the incoming signal. The clock adjustment signal indicates a direction of phase adjustment and can include an amount of phase adjustment. The phase detector receives the samples and provides extended phase alignment commands derived from the samples. The phase alignment control receives the extended phase alignment commands and provides the clock adjustment signal to the clock distributor.
    Type: Application
    Filed: June 30, 2011
    Publication date: January 3, 2013
    Applicant: Intel Mobile Communications GmbH
    Inventor: Holger Wenske
  • Patent number: 8345783
    Abstract: Phase tracking in an OFDM symbol comprises determining a sufficient statistic for CFO and SFO estimation from a differential metric between a current OFDM symbol and a previous OFDM symbol transmitted on the same frequency band. The sufficient statistics corresponding to positive pilot tones are combined with those corresponding to negative pilot tones to estimate the CFO and SFO.
    Type: Grant
    Filed: March 31, 2011
    Date of Patent: January 1, 2013
    Assignee: Olympus Corporation
    Inventors: Dumitru Mihai Ionescu, Haidong Zhu, Abu Amanullah
  • Patent number: 8344771
    Abstract: A delay locked loop (DLL) of a semiconductor integrated circuit includes a first delay line configured to variably delay a source clock signal and output a locked clock signal, a phase comparator configured to compare the phase of the source clock signal with the phase of a feedback clock signal, a second delay line configured to variably delay the locked clock signal, a first delay controller configured to control the first delay time of the first delay line, a second delay controller configured to control the minimum delay time of the second delay line, and an operation mode controller configured to control the first and second delay controllers in response to an output signal of the phase comparator, and switch operation modes of the first and second delay controllers depending on locking state of the delay lines.
    Type: Grant
    Filed: November 2, 2010
    Date of Patent: January 1, 2013
    Assignee: Hynix Semiconductor Inc.
    Inventor: Dong-Suk Shin
  • Patent number: 8344770
    Abstract: A PLL circuit is provided capable of reducing phase noise and facilitating design. In the PLL circuit, a PLL receives a reference frequency and an output from a VC-TCXO, performs a lock operation. In a lock state, a selector selects an output of a first divider that divides the reference frequency. When PLL detects input of reference frequency being lost or an unlock state, the PLL outputs an alarm signal to the selector. When receiving the alarm signal from the PLL, the selector switches from the output of the first divider to an output of a second divider that frequency-divides an output of the VC-TCXO, and outputs the same. Then, a PLL receives an output of the selector and an output of a VCXO and performs a lock operation.
    Type: Grant
    Filed: February 15, 2011
    Date of Patent: January 1, 2013
    Assignee: Nihon Dempa Kogyo Co., Ltd
    Inventor: Minoru Fukuda
  • Patent number: 8345811
    Abstract: A method of achieving reduced modulation range requirement in a Digitally Controlled Oscillator (DCO) which is deployed as part of a DRP (Digital Radio Processor) and tuned to a tuning frequency range having operating-channel center-frequencies, wherein phase difference between consecutive samples is termed as FCW (Frequency Control Word), uses the steps of digitally modifying and limiting the FCW so that the FCW does not exceed known FCW thresholds, e.g., chosen from ?/2, ?/4, ?/8, and redistributing the FCWs while maintaining a cumulative sum of phases and without significant EVM (Error Vector Magnitude) degradation. The FCW threshold can be chosen arbitrarily and need not be in the form of ?/2n. The method uses a FCW limiting algorithm which reduces supply voltage sensitivity of the DCO and enables significant reduction in area of capacitor bank which would be otherwise needed.
    Type: Grant
    Filed: April 2, 2008
    Date of Patent: January 1, 2013
    Assignee: Texas Instruments Incorporated
    Inventors: Sarma S. Gunturi, Jawaharlal Tangudu, Sthanunathan Ramakrishnan, Jayawardan Janardhanan, Debapriya Sahu, Subhashish Mukherjee
  • Patent number: 8340236
    Abstract: A circuit and method of operation for a circuit of a radio system in which a system time is divided into symbols, in which a system clock generator is activated in an operating mode, so that the system time is determined from an output clock signal of the system clock generator by counting, in which the system clock generator is deactivated in a sleep mode, in which an output clock signal of a sleep clock generator is blanked as a function of an output signal of a modulo divider in the sleep mode, and the system time is determined by counting, wherein an output frequency of the output clock signal of the sleep clock generator is a non-integer multiple of a symbol frequency, in which the modulo divider divides the output clock signal of the sleep clock generator by a division factor, and in which the division factor of the modulo divider is produced by changing between at least two integer divisor values.
    Type: Grant
    Filed: October 14, 2009
    Date of Patent: December 25, 2012
    Assignee: Atmel Corporation
    Inventors: Dirk Haentzschel, Lutz Dathe
  • Patent number: 8331519
    Abstract: A frequency detector includes an error measurement unit measuring a time interval between zero-crossing points of an input signal that is modulated. An error conversion unit quantizes the measured time interval using one of modulation time intervals. An error calculation unit calculates a frequency error based upon a difference between the measured time interval and the quantized time interval. An error generation control unit controls whether to output the frequency error based upon the quantized time interval, the calculated frequency error, and a predetermined critical value.
    Type: Grant
    Filed: April 27, 2009
    Date of Patent: December 11, 2012
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sergey Zhidkov, Jun Ho Huh, Ki Seop Kwon
  • Patent number: 8330512
    Abstract: A clock generation circuit of a semiconductor apparatus includes a first phase detection block configured to compare initial phases of a reference clock signal and an output clock signal in response to an operation start signal, and output an initial phase difference detection signal corresponding to a comparison result; a second phase detection block configured to compare phases of the reference clock signal and the output clock signal, and output a phase detection signal corresponding to a comparison result; a variable unit delay block determined in a control range of the delay amount thereof in response to the initial phase difference detection signal, and configured to delay the reference clock signal by a delay amount corresponding to a voltage level of a control voltage and output the output clock signal; and a delay control block configured to generate the control voltage which has the voltage level corresponding to the phase detection signal.
    Type: Grant
    Filed: July 26, 2010
    Date of Patent: December 11, 2012
    Assignee: SK Hynix Inc.
    Inventors: Ki Han Kim, Dong Suk Shin
  • Patent number: 8330510
    Abstract: A phase-locked loop for generating an output signal that has a predetermined frequency relationship with a reference signal, the phase-locked loop comprising a signal generator arranged to generate the output signal, a charge pump arranged to generate current pulses for controlling the signal generator, two control units for controlling a duration of the current pulses generated by the charge pump and a selection unit arranged to select either the first control unit or the second control unit to control the charge pump, wherein a first one of the control units is arranged to continuously monitor a phase-difference between the reference signal and a feedback signal formed from the output signal and to, when selected by the selection unit, control the charge pump to output a current pulse having a duration that is dependent on that phase-difference and a second one of the control units is arranged to, when selected by the selection unit, control the charge pump to output a current pulse of predetermined duratio
    Type: Grant
    Filed: March 5, 2009
    Date of Patent: December 11, 2012
    Assignee: Cambridge Silicon Radio Limited
    Inventors: Pasquale Lamanna, Nicolas Sornin
  • Patent number: 8332681
    Abstract: In a first embodiment of the present invention, a method for operating a device having a device reference clock, in a system including a host with a host reference clock is provided, the method comprising: beginning a link negotiation stage between the device and the host using the device reference clock; during the link negotiation stage, sampling data received from the host to determine a frequency offset of the host reference clock; applying the frequency offset to the device reference clock to create a corrected device reference clock; and completing the link negotiation stage using the corrected device reference clock. This completing may include either continuing the original link negotiation stage or restarting it.
    Type: Grant
    Filed: May 1, 2012
    Date of Patent: December 11, 2012
    Assignee: PLX Technology, Inc.
    Inventor: Philip David Rose
  • Patent number: 8331512
    Abstract: A circuit for performing clock recovery according to a received digital signal (30). The circuit includes at least an edge sampler (105) and a data sampler (145) for sampling the digital signal, and a clock signal supply circuit. The clock signal supply circuit provides edge clock (25) and data clock (20) signals offset in phase from one another to the respective clock inputs of the edge sampler (105) and the data sampler (145). The clock signal supply circuit is operable to selectively vary a phase offset between the edge and data clock signals.
    Type: Grant
    Filed: April 4, 2007
    Date of Patent: December 11, 2012
    Assignee: Rambus Inc.
    Inventors: Hae-Chang Lee, Jared LeVan Zerbe, Carl William Werner
  • Patent number: 8325853
    Abstract: Embodiments of the present invention relate to a system for clock synthesis or data timing recovery. No analog continuous time oscillator is required, all the building blocks of a Frequency Locked Loop/Phase Locked Loop belonging in the digital discrete time domain. From a system-level perspective, the system is characterized by its strong non-linear behavior due to the intrinsic nature of some building blocks. This inherent non-linearity is responsible for some unusual, attractive property of the complete system. The system is able to multiply the input frequency clock by an arbitrarily large factor, ensuring in any case the convergence of the algorithm in two reference clock cycles.
    Type: Grant
    Filed: January 31, 2006
    Date of Patent: December 4, 2012
    Assignee: STMicroelectronics S.r.l.
    Inventor: Carmelo Burgio
  • Patent number: 8325864
    Abstract: A first phase adjustment circuit adjusts phases of a data decision clock signal and a first boundary decision clock signal according to a phase adjustment amount based on an output signal of a data decision circuit and an output signal of a first boundary decision circuit. A second phase adjustment circuit adjusts a phase of a second boundary decision clock signal according to a result of adding the phase adjustment amount and a phase adjustment amount offset. An adaptive equalization control circuit adjusts an equalization coefficient of an equalization circuit according to a data width of an output signal of the equalization circuit based on a logical comparison result between the output signal of the data decision circuit and an output signal of a second boundary decision circuit when the phase adjustment amount offset is changed.
    Type: Grant
    Filed: September 17, 2009
    Date of Patent: December 4, 2012
    Assignee: Fujitsu Limited
    Inventor: Hisakatsu Yamaguchi
  • Patent number: 8311157
    Abstract: A signal recovery circuit capable of expanding the receive margin is provided. The signal recovery circuit comprises for example a clock generator unit CLK_GEN for generating the clock signals CLKa, CLKb, and CLKc, a window width control unit WW_CTL, and a clock data discriminator unit CD_JGE for generating a phase detector signal (EARLY, LATE) when for example a data signal Di pulse edge enters between the CLKa and CLKb, or between the CLKb and CLKc, and the clock generator unit. Along with exerting control based on these phase detection signals to maintain the mutual phase differential of the overall phase of CLKa, CLKb, CLKc so as to prevent intrusion of the above described Di edge, the CLK_GEN also regulates the phase differential between CLKa and CLKb, and the phase differential between CLKb and CLKc based on a signal (Sww) from the WW_CTL.
    Type: Grant
    Filed: January 26, 2009
    Date of Patent: November 13, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Koji Fukuda, Hiroki Yamashita, Daisuke Hamano
  • Patent number: 8306175
    Abstract: A clock and data recovery circuit includes a voltage controlled oscillator for generating an output clock according to a control voltage signal, a loop filter for outputting the control voltage signal according to a current output, a charge pump unit for outputting the current output according to an error signal, and a controller for determining a run length corresponding to input data based on the output clock from the voltage controlled oscillator. The controller further controls at least one of the voltage controlled oscillator, the loop filter and the charge pump unit according to the run length to dynamically adjust loop bandwidth. A method of adjusting loop bandwidth is also disclosed.
    Type: Grant
    Filed: October 26, 2007
    Date of Patent: November 6, 2012
    Assignee: Realtek Semiconductor Corp.
    Inventors: Chao-Cheng Lee, Tzu-Chien Tzeng
  • Patent number: 8306173
    Abstract: A clock regeneration circuit according to the present invention that generates a clock signal that is synchronized to an input signal, includes: a detection section which detects points at which the input signal transitions; a histogram generation section which associates a plurality of partial periods with the transition points, and generates a first histogram indicating an incidence of the transition points for each of the partial periods, the partial periods being generated by dividing a reference period of the clock signal; a calculation processing section which generates a second histogram by calculation processing based on the first histogram, and calculates a phase adjustment value of the clock signal based on the second histogram; and a phase adjustment section which adjusts a phase of the clock signal based on the phase adjustment value.
    Type: Grant
    Filed: February 24, 2009
    Date of Patent: November 6, 2012
    Assignee: Olympus Corporation
    Inventor: Masaharu Yanagidate
  • Patent number: 8306147
    Abstract: A 4× over-sampling data recovery system consists of a charge pump PLL, a 4× over-sampler, a data regenerator and a digital PLL. The charge pump PLL receives a clock signal and generates a plurality of multiplicative clock signals in response to the clock signal. The 4× over-sampler samples a serial data to generate a M-bit signal according to the plurality of multiplicative clock signals, wherein each bit in the serial data is sampled for four times. The data regenerator sequentially receives and combines two M-bit signals to generate a (M+N)-bit signal. The digital PLL divides the (M+N)-bit signal into (N+1) groups of M-bit data and selects a designated M-bit data from the (N+1) groups of M-bit data to generate a P-bit recovery data.
    Type: Grant
    Filed: June 22, 2009
    Date of Patent: November 6, 2012
    Assignee: Sunplus Technology Co., Ltd.
    Inventor: Chia-Hao Hsu
  • Patent number: 8300753
    Abstract: In one embodiment, a method includes accessing a reference clock having a reference clock frequency and reference clock phase; generating an output clock having an output clock phase and output clock frequency that is a function of an analog control voltage setting and a frequency gain curve; fixing the analog control voltage setting to a predetermined voltage; selecting one of the frequency gain curves within a predetermined frequency range of the reference clock frequency at the analog control voltage setting; adjusting the analog control voltage setting to adjust the output clock frequency to be within another predetermined frequency range of the reference clock frequency; and adjusting the output clock phase to be within a predetermined phase range of an input data phase of the input data stream.
    Type: Grant
    Filed: July 27, 2009
    Date of Patent: October 30, 2012
    Assignee: Fujitsu Limited
    Inventors: Nikola Nedovic, Nestor Tzartzanis, William W. Walker
  • Patent number: 8300718
    Abstract: A demodulating circuit includes: a fast Fourier transform circuit which fast Fourier transforms a received signal and outputs a plurality of carrier signals; an output selecting circuit which selects at least two signals from the plurality of carrier signals, the at least two signals including a first signal modulated in accordance with a first modulation method and a second signal modulated in accordance with a second modulation method; an inverse fast Fourier transform circuit which inverse Fourier transforms transmission path characteristic values including a first transmission path characteristic value obtained based on the first signal and a second transmission path characteristic value obtained based on the second signal; and an FFT window control circuit which controls a position of an FFT window based on the inverse Fourier transformed transmission path characteristic values.
    Type: Grant
    Filed: May 18, 2010
    Date of Patent: October 30, 2012
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Naoto Adachi
  • Patent number: 8295423
    Abstract: A system for clockless synchronous data recovery is provided. The system includes an input rate demultiplexer receiving a serial data stream of bits of data transmitted at a bit rate and generating two or more parallel data streams from the serial data stream. One or more delays coupled to the input rate demultiplexer each receives one of the generated parallel serial data streams and delays bits of data and feeds them back to the input rate demultiplexer.
    Type: Grant
    Filed: September 24, 2007
    Date of Patent: October 23, 2012
    Assignee: California Institute of Technology
    Inventors: Seyed-Ali Hajimiri, Behnam Analui
  • Patent number: 8295419
    Abstract: A clock generator circuit for generating synchronization signals for a multiple chip system. The clock generator circuit comprises generation of a synchronization signal from a reference clock and chip global clock with edge detection logic. In high performance server system design with multiple chips, a common practice for server systems is to use feedback clock and delayed reference clock to generate the synchronization signal. The generated synchronization signal is transferred to latches clocked by the global clock to be used for chip synchronization functions. As the system clock frequency is pushed higher, the phase difference between generated synchronization signal clocked by feedback clock and receiving latch clocked by global clock is becoming such a large portion of cycle time that this signal cannot be transferred deterministically.
    Type: Grant
    Filed: October 18, 2010
    Date of Patent: October 23, 2012
    Assignee: International Business Machines Corporation
    Inventors: Charlie C. Hwang, Wiren D. Becker, Timothy G. McNamara, Ching-Lung Tong
  • Patent number: 8295421
    Abstract: Integrated circuits with data communications circuitry are provided. The data communications circuitry on an integrated circuit may receive data that was transmitted from another integrated circuit at a data rate. The data communications circuitry may include oversampling circuitry that oversamples the data to produce an oversampled version of the data at an oversampled data rate. Downsampling circuitry in the data communications circuitry may be used to downsample the oversampled data. The downsampling circuitry may include cascaded groups of registers that store the oversampled data. The outputs of each of the groups of registers may be combined to form a combined parallel output. A downsampling control circuit may have a multiplexer that selects a subset of the signals from the combined parallel output in response to control signals from a transition detector. A middle bit detector may extract a bit value from the selected subset to use as the downsampled output.
    Type: Grant
    Filed: November 10, 2009
    Date of Patent: October 23, 2012
    Assignee: Altera Corporation
    Inventors: Thiam Sin Lai, Siew Leong Lam
  • Patent number: 8289056
    Abstract: Embodiments include implementing a phase detector for a delay-locked loop (DLL) circuit that is operable to detect substantially 270 degree and substantially 540 degree phase differences between two clock signals.
    Type: Grant
    Filed: December 3, 2008
    Date of Patent: October 16, 2012
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Min Xu, Ming-Ju E. Lee
  • Patent number: 8290107
    Abstract: A clock data recovery circuit that supplies stable reference clocks to the object respectively by shortening the time of bit synchronization with each received burst data signal regardless of jittering components included in the received burst data signal, includes an interpolator that generates a reference clock having the same frequency as that of a received burst data signal and two types of determination clocks having a phase that is different from that of the reference clock respectively; and a phase adjustment control circuit that can change the phase of the reference clock in units of M/2?. After beginning receiving of a burst data signal, the clock data recovery circuit sets a large phase change value at the first phase adjustment timing and reduces the change value in the second and subsequent phase adjustment timings, thereby realizing quick bit synchronization with the received burst data signal to generate a reference clock.
    Type: Grant
    Filed: January 27, 2009
    Date of Patent: October 16, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masayuki Takase, Hideki Endo, Koji Fukuda, Kenichi Sakamoto
  • Patent number: 8284884
    Abstract: A method of frequency search for a digitally controlled oscillator (DCO) with multiple sub-bands. The method comprises providing multiple workable pre-control codes, each control code comprising a most significant bit (MSB), corresponding to each frequency of the DCO for selection, selecting one of the workable pre-control codes according to the MSBs thereof, and providing the selected control code to the DCO.
    Type: Grant
    Filed: June 15, 2007
    Date of Patent: October 9, 2012
    Assignee: Mediatek Inc.
    Inventor: Hsiang-Hui Chang
  • Patent number: 8284816
    Abstract: A spread spectrum clock signal generator modulates a reference clock signal based on a spread spectrum frequency profile and includes a phase-lock loop for generating a spread spectrum clock signal by aligning a phase of the modulated reference clock signal with a phase of the spread spectrum clock signal. The spread spectrum clock signal generator also includes a loop modulator for modulating the spread spectrum clock signal based on the spread spectrum frequency profile. Because the spread spectrum clock signal generator modulates both the reference clock signal and the spread spectrum clock signal based on the spread spectrum frequency profile, the spread spectrum clock signal has a non-distorted frequency profile and low phase jitter.
    Type: Grant
    Filed: June 1, 2009
    Date of Patent: October 9, 2012
    Assignee: Integrated Device Technology, Inc.
    Inventor: Daniel M. Clementi
  • Patent number: 8284885
    Abstract: A clock and data recovery (CDR) circuit is provided. The CDR circuit receives a data signal and generates a clock signal. The CDR circuit comprises an oscillator, a phase detector, and a first voltage-to-current (V-to-I) converter. The oscillator generates the clock signal according to an oscillation voltage. The phase detector receives the data signal. The phase detector comprises a mixer for detecting a phase difference between the data clock and the clock signal and generating a phase detection signal which represents the phase difference. The first V-to-I converter receives the phase detection signal and generates a first current signal according to a voltage level of the phase detection signal to vary the oscillation voltage.
    Type: Grant
    Filed: October 1, 2009
    Date of Patent: October 9, 2012
    Assignee: National Taiwan University
    Inventors: Jr-I Lee, Ke-Chung Wu
  • Patent number: 8284886
    Abstract: A system and method for low-cost performance and compliance testing of local oscillators and transmitters for wireless RF applications. A preferred embodiment comprises observing a digital signal from within an RF circuit, manipulating the signal with digital signal processing techniques, and determining if the RF circuit passes a test based upon results from the manipulating. Since the signal is clocked at a much lower frequency than an RF output of the RF circuit and the manipulation is performed digitally, testing can be performed at different stages of the production cycle and expensive test equipment can be eliminated.
    Type: Grant
    Filed: January 16, 2004
    Date of Patent: October 9, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Robert B. Staszewski, Dirk Leipold, Elida de-Obaldia
  • Patent number: 8278984
    Abstract: A loop filter for a phase-locked loop that generates an output signal having a predetermined phase relationship with a reference signal, the loop filter being arranged to control a signal generator that forms the output signal in dependence on a phase error between the output signal and the reference signal by outputting a control signal for controlling the signal generator in dependence thereon, the loop filter being arranged to form the control signal to comprise a proportional component representative of an instantaneous magnitude of the phase difference and an integral component representative of an integral of the phase difference, the loop filter comprising a proportional path arranged to receive a signal representative of the instantaneous magnitude of the phase difference and form the proportional component of the control signal in dependence thereon and an integral path arranged to receive a signal representative of the instantaneous magnitude of the phase difference and form the integral component o
    Type: Grant
    Filed: March 5, 2009
    Date of Patent: October 2, 2012
    Assignee: Cambridge Silicon Radio Limited
    Inventors: Pasquale Lamanna, Nicolas Sornin
  • Patent number: 8275081
    Abstract: An approach is provided for supporting carrier synchronization in a digital broadcast and interactive system. A carrier synchronization module receives one or more signals representing a frame that includes one or more overhead fields (e.g., preamble and optional pilot blocks and one or multiple segments separated by pilot blocks). The module estimates carrier frequency and phase on a segment by segment basis and tracks frequency between segments. Carrier phase of the signal is estimated based upon the overhead field. Estimates carrier phase of random data field are determined based upon the estimated phase values from the overhead fields, and upon both the past and future data signals. Further, the frequency of the signal is estimated based upon the overhead fields and/or the random data field. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.
    Type: Grant
    Filed: September 29, 2010
    Date of Patent: September 25, 2012
    Assignee: DTVG Licensing, Inc.
    Inventors: Yimin Jiang, Feng-Wen Sun, Lin-Nan Lee, Neal Becker
  • Patent number: 8275025
    Abstract: Methods and apparatus are provided for pseudo asynchronous testing of receive paths in serializer/deserializer (SerDes) devices. A SerDes device is tested by applying a source of serial data to a receive path of the SerDes device during a test mode. The receive path substantially aligns to incoming data using a bit clock. A phase is adjusted during the test mode of the bit clock relative to the source of serial data to evaluate the SerDes device. The source of serial data may be, for example, a reference clock used by a phase locked loop to generate the bit clock. The phase of the bit clock can be directly controlled during the test mode, for example, by a test phase control signal, such as a plurality of interpolation codes that are applied to an interpolator that alters a phase of the bit clock.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: September 25, 2012
    Assignee: LSI Corporation
    Inventors: Christopher J. Abel, Parag Parikh, Vladimir Sindalovsky
  • Patent number: 8270552
    Abstract: An apparatus for transferring data in a non-spread domain to a spread domain. The apparatus comprises a first-in-first-out (FIFO) memory; a write pointer generator adapted to generate a write pointer for writing data into the FIFO memory in response to a non-spread clock signal; a spread-clock generator adapted to generate a spread clock signal based on the non-spread clock signal; a read pointer generator adapted to generate a read pointer for reading data from the FIFO memory in response to the spread clock signal; and a controller adapted to control the spread-clock generator in response to the read and write pointers indicating predetermined potential data overflow or underflow of the FIFO memory.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: September 18, 2012
    Assignee: Maxim Integrated Products, Inc.
    Inventor: Mustafa Ertugrul Oner
  • Patent number: 8264607
    Abstract: A method of sampling phase calibration and a device thereof is suitable for an analog-to-digital converter and phase lock loop (ADC-PLL). The ADC-PLL conducts sampling on a periodic analog signal according to a sampling phase so as to produce a plurality of digital signals. The sampling phase calibration device includes a storage unit, a motion-detecting unit and a control unit. The motion-detecting unit is to calculate the number of motion data corresponding to a sampling phase. The control unit is coupled to the motion-detecting unit for changing the sampling phase so as to obtain the number of motion data corresponding to each sampling phase and selecting the sampling phase corresponding to the minimum number of motion data as an optimal sampling phase. The ADC-PLL can correctly sample an analog signal by using the optimal sampling phase and reduce the influence of clock jitter to the minimum.
    Type: Grant
    Filed: September 16, 2010
    Date of Patent: September 11, 2012
    Assignee: Sunplus Technology Co., Ltd.
    Inventors: Chian-Wen Chen, Wei-Lung Lu, Jui-Yao Lee
  • Patent number: 8265219
    Abstract: A method and apparatus for fast PLL initialization have been disclosed where control of a VCO is based on a selected control signal which is based upon either a comparison signal or a prespecified signal.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: September 11, 2012
    Assignee: Integrated Device Technology, Inc.
    Inventor: Stanley Hronik
  • Patent number: 8265102
    Abstract: Systems and techniques are disclosed wherein a gated pilot signal can be re-acquired faster by searching a last known pilot offset and/or searching a last coset in which the last pilot signal was found.
    Type: Grant
    Filed: June 10, 2010
    Date of Patent: September 11, 2012
    Assignee: QUALCOMM Incorporated
    Inventor: Abhay Arvind Joshi
  • Patent number: 8249533
    Abstract: A rapidly adjustable local oscillation (LO) module for use in a radio transmitter or a radio receiver includes an oscillation generating module and a high frequency switching module. The oscillation generating module is operably coupled to generate a plurality of local oscillations. The high frequency switching module is operably coupled to, for a first one of a plurality of transmission paths, provide one of the plurality of local oscillations when a first transmission path selection indication is in a first state and provide another one of the plurality of local oscillations when the first transmission path selection indication is in a second state and, for a second one of the plurality of transmission paths, provide the one of the plurality of local oscillations when a second transmission path selection indication is in a first state and provide the another one of the plurality of local oscillations when the second transmission path selection indication is in a second state.
    Type: Grant
    Filed: November 14, 2005
    Date of Patent: August 21, 2012
    Assignee: Vixs Systems, Inc.
    Inventors: Bojan Subasic, Mathew A. Rybicki
  • Patent number: 8243867
    Abstract: A receiver may include a clock and data recovery circuit, a detection circuit and a sampling clock generator. The clock and data recovery circuit may receive first data and sample the first data to generate recovered data in response to a reception sampling clock signal. The detection circuit may detect a frequency difference between a transmission sampling clock signal and the reception sampling clock signal by comparing the first data and the reception sampling clock signal to generate a frequency difference detection signal. The sampling clock generator may generate the reception sampling clock signal based on the frequency difference detection signal and a first reference clock signal. Therefore, a communication system including the receiver may effectively reduce a jitter noise.
    Type: Grant
    Filed: December 5, 2008
    Date of Patent: August 14, 2012
    Assignee: Samsung Electronics Co. Ltd.
    Inventor: Jong-Shin Shin
  • Patent number: 8243865
    Abstract: A disclosed data processing apparatus includes: a binarization unit binarizing input data based on a threshold voltage; a capture unit capturing data from a binary output binarized by the binarization unit; a duty cycle detection unit detecting a duty cycle of the binary output; and a control unit controlling a level of the input data based on the duty cycle detected by the duty cycle detection unit.
    Type: Grant
    Filed: June 15, 2007
    Date of Patent: August 14, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Nobunari Tsukamoto, Hidetoshi Ema
  • Patent number: 8238413
    Abstract: An adaptive equalizer for high-speed serial data comprises a programmable equalizer for equalizing an input serial data signal to generate an equalized serial data signal, wherein the equalization is based on an optimal equalization mode; a signal quality meter for computing an eye width indication based on the equalized serial data signal, wherein the eye width indication is an indicative of the quality of the equalized serial data signal; and a decision unit for determining the optimal equalization mode based on the eye width indication.
    Type: Grant
    Filed: June 23, 2010
    Date of Patent: August 7, 2012
    Assignee: TranSwitch Corporation
    Inventors: Wolfgang Roethig, Genady Veytsman
  • Patent number: 8238506
    Abstract: A high-accuracy and computational efficient phase-discriminating device is provided and includes a phase-discriminating unit. The phase-discriminating unit converts an input and a reference signals into an input and a reference sequences respectively by a one-bit A/D conversion operation, determines a first value, an in-phase component and a quadrature component of the input signal in response to the input and the reference sequences, and produces an estimated phase of the input signal according to a relation among the first value, the in-phase component and a polarity of the quadrature component, wherein the first value is a certain integer being one of a first integer and a second integer, the first integer is a sampling count of the one-bit A/D conversion operation for producing the input sequence, and the second integer is a summation of an absolute value of the in-phase component and that of the quadrature component.
    Type: Grant
    Filed: January 6, 2009
    Date of Patent: August 7, 2012
    Assignee: National Applied Research Laboratories
    Inventors: Chieh-Fu Chang, Ru-Muh Yang, Ming-Seng Kao
  • Patent number: 8238504
    Abstract: A clock generation circuit includes: a first determination circuit that detects an input signal at a first phase position based on first frequency signal; a second determination circuit that detects the input signal at a second phase position based on second frequency signal; a phase detector that compares output of the first determination circuit and output of the second determination circuit; a first summing circuit which sums comparison result and first control signal; a second summing circuit which sums comparison result and second control signal; a first voltage controlled oscillation circuit which receives output of the first summing circuit and outputs the first frequency signal; a second voltage controlled oscillation circuit which received output of the second summing circuit and outputs the second frequency signal; and a phase adjustment circuit which generates first control signal and second control signal based on first frequency signal and second frequency signal.
    Type: Grant
    Filed: December 8, 2009
    Date of Patent: August 7, 2012
    Assignee: Fujitsu Limited
    Inventors: Yasumoto Tomita, Masaya Kibune, Hirotaka Tamura
  • Patent number: 8238402
    Abstract: The present invention provides a communications system, node and method of operation for forming a wireless network from independently operating nodes that have the ability to self-synchronize with each other, independently determine master and slave modes of operation to cooperate as a network, and independently vary those functions to adjust to changes in the network.
    Type: Grant
    Filed: December 22, 2009
    Date of Patent: August 7, 2012
    Assignee: Cornell University
    Inventors: Rajeev K. Dokania, Xiao Y. Wang, Alyssa B. Apsel
  • Patent number: 8237512
    Abstract: According to an embodiment, a digitally controlled oscillator outputs an oscillation signal having an oscillation frequency according to an oscillator tuning word. The digitally controlled oscillator includes a control unit and an oscillator. The control unit divides the oscillator tuning word of N bits into upper (N?A) (A?1 and N>A) bits and lower A bits, converts the upper (N?A) bits into a first code to perform Binary control of (N?A) bits and converts the lower A bits into a second code to perform Unary control of (2^(A+1)?2) bits, and outputs the conversion results, and the oscillator outputs oscillation signals having oscillation frequencies according to the first and second codes output from the control unit.
    Type: Grant
    Filed: September 20, 2010
    Date of Patent: August 7, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Hiroyuki Kobayashi
  • Patent number: 8238505
    Abstract: The invention relates to a method or to a correspondingly equipped circuit for line-coupled generation of a clock (t), wherein the clock (t) is controlled in relation to a synchronization signal (hs) and by means of a closed loop (FLL) with respect to the phase and/or the frequency in relation to the synchronization signal (hs); wherein a plurality (n) of at least two count values (cn, c0-c7) is determined, wherein each of the count values (cn, c0-c7) is determined with at least one count duration number (z) of consecutive periods of the synchronization signal (hs), and wherein each of the count values (cn, c0-c7) is determined offset relative to at least one further count value (cn, c0-c7) with a count offset (v) which is different from the count duration number of consecutive periods of the synchronization signal (hs).
    Type: Grant
    Filed: March 8, 2007
    Date of Patent: August 7, 2012
    Assignee: Entropic Communications, Inc.
    Inventor: Markus Waldner