By Interpolating Or Maximum Likelihood Detecting Patents (Class 369/59.22)
  • Patent number: 10009195
    Abstract: An equalizer and method is implemented to improve the performance of a communication system based on multi-level amplitude modulation schemes. The equalizer may include a linear equalization circuit including a plurality of time delayed taps and configured to receive an input signal and generate an output signal. The equalizer may further include a nonlinear circuit configured to receive signals from at least a portion of the time delayed taps and generate at least a portion of a difference between the signals, the output signal based at least in part on the difference.
    Type: Grant
    Filed: June 16, 2017
    Date of Patent: June 26, 2018
    Assignee: Finisar Corporation
    Inventors: Thang Pham, Chengpin Yu
  • Patent number: 9954647
    Abstract: The present invention discloses an ML (Maximum Likelihood) detector comprising: a search value selecting circuit selecting a first-layer search value; and an ML detecting circuit.
    Type: Grant
    Filed: March 21, 2017
    Date of Patent: April 24, 2018
    Assignee: REALTEK SEMICONDUCTOR CORPORATION
    Inventors: Chung-Yao Chang, Chuan-Hu Lin, Yi-Syun Yang
  • Patent number: 9374170
    Abstract: An optical receiving device includes: an adaptive equalizer that includes a position estimation unit configured to estimate, based on a first signal component and a second signal component of a reception signal generated by reception of a training sequence pattern transmitted from an optical transmitter, a symbol position of the reception signal, and generates an estimated symbol position, a delay unit configured to provide a delay difference between the first signal component and the second signal component, a control unit configured to set a plurality of symbol displacement amount candidates of displacement amounts for the estimated symbol position, causes the delay unit to generate a plurality of delay differences, and generates a channel estimation symbol position used for channel estimation, and an error rate calculation unit configured to calculate an error rate of the signal restored by an adaptive equalization unit.
    Type: Grant
    Filed: December 4, 2014
    Date of Patent: June 21, 2016
    Assignee: FUJITSU LIMITED
    Inventors: Masato Oota, Tomoki Katou, Kazuhiko Hatae, Hisao Nakashima, Manabu Yamazaki
  • Patent number: 9324370
    Abstract: An embodiment of a data-read path includes a defect detector and a data-recovery circuit. The defect detector is operable to identify a defective region of a data-storage medium, and the data-recovery circuit is operable to recover data from the data-storage medium in response to the defect detector. For example, such an embodiment may allow identifying a defective region of a data-storage disk caused, e.g., by a scratch or contamination, and may allow recovering data that was written to the defective region.
    Type: Grant
    Filed: August 20, 2010
    Date of Patent: April 26, 2016
    Assignee: STMICROELECTRONICS, INC.
    Inventors: Shayan Srinivasa Garani, Sivagnanam Parthasarathy
  • Patent number: 9129645
    Abstract: A data demodulation method may include converting an analog signal into a digital signal; detecting a peak point of a reproduced signal; creating a plurality of preliminary data rows for creating demodulated data; and creating demodulated data. The preliminary data rows may include the first individual data to be identified on the basis of the interval, and are formed of the first individual data of plural bits. Creating a plurality of preliminary data rows may use a template listing part of, or all of, a plurality of bit patterns being formed of second individual data.
    Type: Grant
    Filed: August 26, 2013
    Date of Patent: September 8, 2015
    Assignee: NIDEC SANKYO CORPORATION
    Inventors: Shigeo Nakajima, Yoichi Isono, Katsuhisa Higashi
  • Patent number: 8988814
    Abstract: According to one embodiment, a storage device includes a data conversion unit that coverts user data of n bits, into m three-ary symbols, a recording medium that records the symbols as a signal of any one of three levels corresponding to values of the symbols, and a Viterbi equalizer that performs equalization of the m symbols simultaneously based on a signal read from the recording medium while setting the number of states as a power of 3 and using a trellis diagram having 2n branches, and calculates 2n likelihoods.
    Type: Grant
    Filed: September 3, 2014
    Date of Patent: March 24, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kohsuke Harada, Akihiro Yamazaki, Nobuhiro Maeto, Kazuto Kashiwagi, Tomokazu Okubo, Naoki Tagami
  • Patent number: 8947991
    Abstract: A method of calculating a reliability effective in a decoding process of hologram. An optical information reproducing apparatus that reproduces information with the use of the holography includes an image acquisition unit that reproduces two-dimensional data from a hologram disc, an image equalization unit that makes the two-dimensional data equal to target data having a target PR characteristic, a soft output decoding unit that decodes output data of the image equalization unit on the basis of the PR characteristic, and outputs a decoded result having a reliability, and an error correction unit that conducts an error correction of the data on the basis of the decoded result.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: February 3, 2015
    Assignee: Hitachi Consumer Electronics Co., Ltd.
    Inventors: Yusuke Nakamura, Hajime Ishihara
  • Patent number: 8787135
    Abstract: Provided is a signal processing device including: an adaptive filter; a PRML circuit for sequentially generating binarized data from a filtered reproduced waveform by sampling at sampling points in a period based on a clock signal and sequentially generating a partial response waveform which is to be the target waveform from the binarized data; a calculating unit for sequentially calculating first phase errors from a difference between the target waveform and the filtered reproduced waveform; a limiting unit for outputting second phase errors by excluding a specific phase error from the first phase errors; and a clock generating unit for generating the clock signal of a frequency corresponding to the second phase errors; wherein the specific phase error includes a phase error at a time when the partial response waveform reaches a specific level which excludes at least a level not less than a predetermined amplitude level.
    Type: Grant
    Filed: February 17, 2012
    Date of Patent: July 22, 2014
    Assignee: Mitsubishi Electric Corporation
    Inventors: Masayuki Omaki, Kenya Nakai, Nobuo Takeshita
  • Patent number: 8743671
    Abstract: A recording adjustment method capable of controlling an edge position of a mark with high accuracy. Based on an acquired read-out signal waveform, a starting position of a last pulse is adjusted such that a so-called L-SEAT shift value for an end edge of the mark becomes minimum.
    Type: Grant
    Filed: April 3, 2013
    Date of Patent: June 3, 2014
    Assignee: Hitachi Consumer Electronics Co., Ltd.
    Inventors: Takahiro Kurokawa, Hiroyuki Minemura
  • Patent number: 8717697
    Abstract: According to one embodiment, there is provided a controller including an interference cancelling module, a boosting module, and a decoding module. The interference cancelling module generates a first correction signal by cancelling an interference component from an adjacent track in a signal read from a target track of a disk medium. The boosting module generates a second correction signal by boosting a low frequency component of a signal corresponding to the first correction signal. The decoding module decodes a signal based on the second correction signal.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: May 6, 2014
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yosuke Kondo, Kohsuke Harada, Kenji Yoshida, Akihiro Yamazaki, Kazuhito Ichihara
  • Patent number: 8705665
    Abstract: A process for computing Log-Likelihood-ratios (LLRs) in a detector of a wireless communication receiver is disclosed, with the, LLRs being used by a channel decoder. A signal is received from a telecom front end, the signal corresponding to data belonging to a finite set of constellation symbols, each constellation symbol being arranged in a lattice constellation impaired by additive noise and a multiplicative channel. A limited set of distances representative of Euclidian distances between the received signal and a finite set of predetermined constellation symbols are computed, possibly multiplied by the channel. A set of soft decision LLRs are derived from the computed set of distances under the constraint of a limited length of the list of distances. The derived LLRs are completed by clipping values read from a look-up table which is simultaneously addressed by the values of the SNR and a bit index.
    Type: Grant
    Filed: February 14, 2011
    Date of Patent: April 22, 2014
    Assignee: ST-Ericsson SA
    Inventors: Andrea Ancora, Sebastien Aubert
  • Patent number: 8654474
    Abstract: Various embodiments of the present inventions are related to initialization of decoder-based filter calibration, and in particular to initially using either a detector output or unconverged data from the decoder to train filter coefficients in a noise predictive calibration engine until data sectors converge in the decoder and can be used to train filter coefficients.
    Type: Grant
    Filed: June 15, 2012
    Date of Patent: February 18, 2014
    Assignee: LSI Corporation
    Inventors: Yang Han, Madhusudan Kalluri, Shaohua Yang, Weijun Tan
  • Patent number: 8599670
    Abstract: A Viterbi detector includes an ACS circuit that performs addition of a path metric and branch metrics, comparison of the path metric values and path selection based on the result of comparison. The ACS circuit performs a path decision based on the path metric values and the reproduced signal supplied to the Viterbi detector at the time instant that is a specified number of channel clocks earlier during the path selection. The ACS circuit selects a mark-continuing path if the reproduced signal at the time instant that is the specified number of channel clocks earlier has an amplitude corresponding to any mark, and performs path decision based on the path metric values if the reproduced signal does not have the amplitude corresponding to any mark.
    Type: Grant
    Filed: May 15, 2008
    Date of Patent: December 3, 2013
    Assignee: NEC Corporation
    Inventor: Hiromi Honma
  • Patent number: 8582412
    Abstract: This invention allows super-resolution reproduction with which a better bER value is attainable, when information is recorded by a random pattern including a mark length not longer than a resolution limit, by use of a highly versatile signal decoding method. Information is recorded as marks and spaces coded by RLL(1,7) modulation, which each of the marks and spaces have one of a plurality of lengths, and 2T marks and 2T spaces of the marks and spaces being formed are shorter than 0.12 ?m. An information recording layer (20) includes a reproduction film (21) and a reflective film (22) which are provided in this order from a side from which reproducing light is incident, which reproduction film is made of (i) zinc oxide, (ii) strontium titanate, (iii) titanium oxide, (iv) cerium oxide, or (v) a material including at least one of the (i) through (iv), and which reflective film is made of tantalum or titanium.
    Type: Grant
    Filed: April 25, 2012
    Date of Patent: November 12, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Go Mori, Hirohisa Yamada, Masaki Yamamoto, Yasuhiro Harada, Hideharu Tajima, Shigemi Maeda, Yoshiteru Murakami
  • Patent number: 8531932
    Abstract: In a optical disc system with constraint length equal to or greater than 5, under assumption that continuous 2T count included in a predetermined evaluation bit array is denoted by i and that length of evaluation bit array of interest is given by (5+2i), judgment is passed on whether binary bit arrays include the evaluation bit array. Previously prepared are the error vectors calculated on the basis of target signals corresponding to the evaluation bit arrays and the target signals derived from the binary bit arrays, and the selection of a desired error vector is performed depending on the result of the judgment. At the same time, an equalized error vector is calculated from the target signal derived from the binary bit array and the reproduced signal, and the inner product of the equalized error vector and the selected error vector is calculated.
    Type: Grant
    Filed: October 29, 2009
    Date of Patent: September 10, 2013
    Assignee: Hitachi Consumer Electronics Co., Ltd.
    Inventors: Yusuke Nakamura, Koichiro Nishimura, Hiroyuki Minemura, Takahiro Kurokawa
  • Patent number: 8514682
    Abstract: A reproduction signal evaluation method evaluates the quality of a reproduction signal reproduced from an information recording medium based on a binary signal generated from the reproduction signal using a PRML signal processing system. A pattern extraction step extracts, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step computes a differential metric based on the binary signal; an extraction step extracts the differential metric which is not greater than a predetermined signal processing threshold; a step determines a mean value of the differential metrics which are not greater than the signal processing threshold and extracted in the extraction step; a standard deviation computing step determines a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step evaluates a quality of the reproduction signal using the standard deviation.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: August 20, 2013
    Assignees: Panasonic Corporation, Sony Corporation
    Inventors: Harumitsu Miyashita, Yasumori Hino, Junya Shiraishi, Shoei Kobayashi
  • Patent number: 8498188
    Abstract: Target levels in the PRML method are adaptively set under conditions of simplicity and a low cost. A method of setting a target level for reproduction of an optical information recording medium includes: a step of producing a reproduction signal from reflected light of laser light irradiated to an optical information recording medium; a step of performing waveform equalization processing, which depends on a predetermined partial response characteristic, on the reproduction signal to produce a waveform-equalized reproduction signal; a step of detecting peak levels for marks and spaces of a predetermined number of symbols from the waveform-equalized reproduction signal irrespective of a condition for a symbol adjoining each symbol; and a setting step of determining and setting values of a plurality of target levels, which is employed in Viterbi decoding and is arrayed with non-equal intervals among them, on the basis of a relative relationship among the detected peak levels.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: July 30, 2013
    Assignee: Taiyo Yuden Co., Ltd.
    Inventor: Hiroya Kakimoto
  • Patent number: 8483028
    Abstract: Provided is a recording adjustment method capable of controlling an edge position of a mark with high accuracy. Based on the acquired read-out signal waveform, a starting position of a last pulse is adjusted such that a so-called L-SEAT shift value for an end edge of the mark becomes minimum.
    Type: Grant
    Filed: March 2, 2010
    Date of Patent: July 9, 2013
    Assignee: Hitachi Consumer Electronics Co., Ltd.
    Inventors: Takahiro Kurokawa, Hiroyuki Minemura
  • Patent number: 8467281
    Abstract: Described are techniques for identifying a data storage volume exhibiting a performance problem. First information indicating a sorted ordering of a plurality of maximum response times is displayed for a plurality of data storage volume. A first of the plurality of data storage volumes having a largest one of the plurality of maximum response times is selected. In response to such selecting, additional information is displayed in the user interface about the first data storage volume. The additional information includes at least one workload or performance characteristic of the first data storage volume.
    Type: Grant
    Filed: September 17, 2010
    Date of Patent: June 18, 2013
    Assignee: EMC Corporation
    Inventors: Julio A. Colon, Dan Aharoni, Hagay Dagan, Gil Ratsaby, Taojun Wu
  • Patent number: 8462602
    Abstract: A data recovery device including an analog to digital converter (ADC), a filtering-equalizing unit, a zero crossing detector, a data phase locked loop, a data mapping unit and an estimation unit is provided. The ADC converts a radio frequency signal to a plurality of sampling data points. The sampling data points are converted to a plurality of retiming data points and a clock signal by the filtering-equalizing unit, the zero crossing detector and the data phase locked loop. The data mapping unit selects a plurality of maximum data points and minimum data points from the returning data points, and determines whether to map the maximum data points and the minimum data points to other levels for partially reconstructing the retiming data points. The estimation unit recovers the reconstructed retiming data points to a modulation signal.
    Type: Grant
    Filed: March 4, 2011
    Date of Patent: June 11, 2013
    Assignee: Sunplus Technology Co., Ltd.
    Inventors: Shih-Hsien Liu, Zhieng-Chung Chen
  • Patent number: 8441905
    Abstract: This invention allows super-resolution reproduction with which a better bER value is attainable, when information is recorded by a random pattern including a mark length not longer than a resolution limit, by use of a highly versatile signal decoding method. Information is recorded as marks and spaces coded by RLL(1,7) modulation, which each of the marks and spaces have one of a plurality of lengths, and 2T marks and 2T spaces of the marks and spaces being formed are shorter than 0.12 ?m. An information recording layer (20) includes a reproduction film (21) and a reflective film (22) which are provided in this order from a side from which reproducing light is incident, which reproduction film is made of (i) zinc oxide, (ii) strontium titanate, (iii) titanium oxide, (iv) cerium oxide, or (v) a material including at least one of the (i) through (iv), and which reflective film is made of tantalum or titanium.
    Type: Grant
    Filed: June 11, 2010
    Date of Patent: May 14, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Go Mori, Hirohisa Yamada, Masaki Yamamoto, Yasuhiro Harada, Hideharu Tajima, Shigemi Maeda, Yoshiteru Murakami
  • Patent number: 8437231
    Abstract: A servo control device includes a plurality of reproduction channels, a plurality of analog/digital (A/D) converters, a servo error detecting circuit that generates a servo error signal, a servo signal processing device that executes predetermined processing for the servo error signal to generate a control signal, and a sampling frequency converter that converts the sampling frequency between the servo error detecting circuit and the servo signal processing device. A first clock is included as a sampling clock of the A/D converters and a processing clock of the servo error detecting circuit. A second clock is included as a processing clock of the servo signal processing device. The sampling frequency converter converts the sampling frequency by processing the servo error signal by the servo error detecting circuit in synchronization with the first clock and processing the signal processed in synchronization with the first clock in synchronization with the second clock.
    Type: Grant
    Filed: June 26, 2012
    Date of Patent: May 7, 2013
    Assignee: Sony Corporation
    Inventor: Nobuyoshi Kobayashi
  • Patent number: 8437234
    Abstract: A signal processing device with dynamic phase detector switching includes a first phase detector of a first type, a second phase detector of a second type, and a mixing device to switch between using output from the first phase detector and output from the second phase detector in real time based on specified changes in an input signal being fed to the signal processing device.
    Type: Grant
    Filed: April 25, 2012
    Date of Patent: May 7, 2013
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Rafel Jibry
  • Patent number: 8432780
    Abstract: An exemplary Viterbi decoding apparatus includes a Viterbi decoder and a level information generator. The Viterbi decoder is arranged for generating a first binary signal by decoding an input signal according to target level information. The level information generator is arranged to support a plurality of different hardware configurations each for level information generation, and operate in a target hardware configuration among the different hardware configurations to generate the target level information to the Viterbi decoder.
    Type: Grant
    Filed: May 10, 2012
    Date of Patent: April 30, 2013
    Assignee: Mediatek Inc.
    Inventors: Chih-Ching Yu, Chih-Chung Li
  • Patent number: 8416666
    Abstract: The present invention is related to systems and methods for characterizing circuit operation, and more particularly to systems and methods for modifying a data decoding process.
    Type: Grant
    Filed: April 20, 2012
    Date of Patent: April 9, 2013
    Assignee: LSI Corporation
    Inventors: Fan Zhang, Yang Han, Anatoli A. Bololov, Mikhail I. Grinchuk, Shaohua Yang
  • Patent number: 8406103
    Abstract: A data recovery device including a filter, a tilt detection unit, a tilt cancellation unit and a data conversion unit is provided. The filter filters a radio-frequency data stream to generate an original data stream. The tilt detection unit synthesizes a tangential push-pull data stream by employing a first to a fourth data streams, and generates a tilt direction signal according to symmetry of a curve composed by the tangential push-pull data stream. The tilt cancellation unit detects a plurality of rising areas and falling areas of the original data stream, and reconstructs a plurality of data points corresponding to the rising areas or falling areas in the original data stream so as to generate a tilt repair data stream. The data conversion unit recovers the tilt repair data stream to a modulation signal.
    Type: Grant
    Filed: January 4, 2012
    Date of Patent: March 26, 2013
    Assignee: Sunplus Technology Co., Ltd.
    Inventors: Yen-Chien Cheng, Yung-Chi Yang
  • Patent number: 8385174
    Abstract: A method for evaluating a read signal obtained by irradiating a medium with a laser beam through an objective lens and reading data from the reflected laser beam by a PRML detection method is provided. The method includes: a sampling step of sampling the data obtained from the reflected laser beam at clock timings to obtain sampled values; and a step of, when a constraint length of a PR class in the PRML detection method is an even number, computing an intermediate sampled value for evaluation using at least adjacent two of the sampled values arranged in the order sampled at the clock timings. The provided method is an objective evaluation method when the PRML detection method is used, whereby the selection of a recording medium and a reading apparatus is facilitated.
    Type: Grant
    Filed: November 30, 2011
    Date of Patent: February 26, 2013
    Assignee: TDK Corporation
    Inventor: Takashi Kikukawa
  • Patent number: 8363530
    Abstract: According to the present invention, a first error pattern caused by a shift of a bit relating to a recording mark or a space of a shortest length and a second error pattern caused by an edge shift of the recording mark are used. For each of a plurality of error patterns, a pattern shift obtained by normalizing a difference between a square of a Euclidean distance between the error pattern and a reproduction signal and a square of a Euclidean distance between a correct pattern and the reproduction signal, using a square of a Euclidean distance between the correct pattern and the error pattern is detected. Length and phase errors are calculated by a sum of, or a difference between, a first pattern shift amount obtained by normalization performed using the first error pattern and a second pattern shift amount obtained by normalization performed using the second error pattern.
    Type: Grant
    Filed: April 12, 2011
    Date of Patent: January 29, 2013
    Assignee: Panasonic Corporation
    Inventors: Isao Kobayashi, Harumitsu Miyashita
  • Patent number: 8355307
    Abstract: An optical recording method includes the steps of: encoding record data to generate encoded data which is a combination of marks and spaces; classifying the encoded data according to a combination of a mark length of the mark, a space length of a first space that immediately precedes the mark, and a space length of a second space that immediately succeeds the mark; generating a write pulse train for forming the mark, in which at least one of a leading end edge position, a trailing end edge position and a pulse width of the write pulse train is changed according to a classification result; and irradiating the optical disc medium with the write pulse train generated to form the plurality of marks on the optical disc medium.
    Type: Grant
    Filed: February 24, 2012
    Date of Patent: January 15, 2013
    Assignee: Panasonic Corporation
    Inventors: Atsushi Nakamura, Isao Kobayashi, Shigeru Furumiya
  • Patent number: 8345524
    Abstract: An offset corrector of an information readout apparatus receives a digital signal DRF output from an A/D converter, and performs offset correction. The offset corrector is capable of switching between a level-correction operation that corrects the offset so that the DC level of the shortest period signal included in the readout signal assumes a zero amplitude reference and a HPF operation that matches the level of the readout signal with the zero amplitude reference. The offset corrector corrects the offset in the level correction operation during a normal reproduction, and switches to the HPF operation for offset correction when a defect judgment unit detects a defective area. The information readout apparatus is stable and has a superior performance without a symmetry deviation if there occurs a waveform fluctuation caused by a defect etc.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: January 1, 2013
    Assignee: NEC Corporation
    Inventor: Hiromi Honma
  • Patent number: 8339919
    Abstract: A disk drive is disclosed comprising a head actuated over a disk and control circuitry operable to sample a read signal emanating from the head to generate read samples. First vectors of log-likelihood ratios (LLRs) are generated in response to the read samples, wherein each vector corresponds to a nonbinary symbol q in a set of symbols. The first vectors of LLRs are biased to generate biased vectors of LLRs, and the biased vectors of LLRs are decoded into a data sequence, wherein the biased vectors of LLRs increase an error rate of the data sequence.
    Type: Grant
    Filed: December 14, 2011
    Date of Patent: December 25, 2012
    Assignee: Western Digital Technologies, Inc.
    Inventor: Patrick J. Lee
  • Patent number: 8339918
    Abstract: An optical reading system is provided to improve read signal quality with increasing its linear recording density. An optical recording medium in which the distance from a light incident surface to an information recording layer is less than 100 ?m is irradiated with a laser beam through an objective lens and information stored in the information recording layer is read by means of a PRML detection method. At this time, the constraint length n in the PRML detection method is set to an integer which satisfies 0.5×(?/NA)/(LV/f)?1<n<0.5×(?/NA)/(LV/f)+1, wherein ? represents the wavelength of the laser beam, NA represents the numerical aperture of the objective lens, LV represents the linear velocity of the optical recording medium when recording, and f represents a channel bit frequency when recording.
    Type: Grant
    Filed: September 9, 2008
    Date of Patent: December 25, 2012
    Assignee: TDK Corporation
    Inventors: Takashi Kikukawa, Kazushi Tanaka
  • Patent number: 8331208
    Abstract: An information readout device includes an equalizer and a maximum likelihood detector. The equalizer includes a second-order Volterra filter, and equalizes a readout signal read out from an information recording medium to a predetermined characteristic to output the equalization signal. The maximum likelihood detector outputs a binary signal through maximum likelihood detection based on the equalization signal. By limiting the number of second-order terms of the second-order Volterra filter to three terms or four terms, a nonlinear component can be effectively corrected.
    Type: Grant
    Filed: February 8, 2008
    Date of Patent: December 11, 2012
    Assignee: NEC Corporation
    Inventor: Yutaka Yamanaka
  • Patent number: 8284648
    Abstract: An optical disk apparatus is provided that has a signal processing circuit for equalizing a signal so as to achieve predetermined equalization, in which interference between codes is permitted, by means of an adaptive equalization circuit or the like, and for performing binarization by means of a maximum likelihood decoding circuit in which interference is performed as a rule, and thereby achieves stabilized signal reproduction in a narrow-band transmission. When evaluating the quality of the recorded signal through the use of the recording parameter learning and the reproduction system such as recorded signal verification, the optical disk recording apparatus is capable of highly precisely evaluating the quality of the recorded signal by fixing a circuit characteristic after suspending the optimization operation of the adaptive equalization circuit or the like for optimizing the characteristic by the reproduced signal. An optical disk recording method is also provided.
    Type: Grant
    Filed: November 15, 2007
    Date of Patent: October 9, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Koichiro Nishimura, Junya Iizuka, Manabu Katsuki, Takakiyo Yasukawa
  • Patent number: 8270267
    Abstract: In step S1, the address generator generates address information composed of a sync signal which is recorded on an optical disc, address data and an error correction code for the address data, pre-encodes and supplies it to a modulator. At the same time, a carrier signal generator generates a carrier signal which is to carry the address information, and supplies it to the modulator. In step S2, the modulator makes MSK modulation of the carrier signal supplied from the carrier signal generator on the basis of the pre-encoded address information supplied from the address generator, and supplies a resultant MSK modulation signal to a wobbling unit. In step S3, the wobbling unit forms, on the optical disc, a spiral groove wobbled adaptively to the MSK modulation signal supplied from the modulator. In this optical disc, a given address can be accessed quickly and accurately.
    Type: Grant
    Filed: May 17, 2011
    Date of Patent: September 18, 2012
    Assignee: Sony Corporation
    Inventors: Shoei Kobayashi, Nobuyoshi Kobayashi, Tamotsu Yamagami, Shinichiro Iimura
  • Publication number: 20120230173
    Abstract: An optical disk reproducing apparatus is provided which is capable of supporting even a situation in which a reproduction signal characteristic is changed due to a factor other than recording density of an optical disk by using PRML of different constrained length and capable of improving reading accuracy. The optical disk reproducing apparatus includes a PRML circuit of a first constrained length (for example, 4) and a PRML circuit of a second constrained length (for example, 5). Equalization error values obtained during calculation of equalization learning in respective circuits are compared with each other in a determination circuit. Switching control of a switch is performed so that an output of one of the PRML circuits having a smaller equalization error value is selected.
    Type: Application
    Filed: May 17, 2012
    Publication date: September 13, 2012
    Inventors: Yusuke NAKAMURA, Masakazu IKEDA
  • Patent number: 8264932
    Abstract: An optical disc device and an adjusting method for a recording condition for use with the optical disc device that records data into an optical disc medium by using codes whose shortest run length is 2T and reproduces the recorded data by using an adaptive equalizing procedure and a PRML procedure, wherein the recording condition is so adjusted that a reproduced signal with desired quality can be obtained, by using, as the adaptive equalizing procedure, a procedure in which a tap coefficient Cn is set to a value obtained by averaging values of a tap coefficient an renewed by a LMS method, located symmetrically with each other along the time axis.
    Type: Grant
    Filed: July 27, 2011
    Date of Patent: September 11, 2012
    Assignee: Hitachi Consumer Electronics Co., Ltd.
    Inventors: Hiroyuki Minemura, Takahiro Kurokawa
  • Patent number: 8254234
    Abstract: A method for rating an information recording medium according to the present invention includes the steps of: receiving a digital read signal, which has been generated based on an analog read signal representing information that has been read from the information recording medium, and shaping the waveform of the digital read signal; subjecting the shaped digital read signal to maximum likelihood decoding, thereby generating a binarized signal showing a result of the maximum likelihood decoding; and calculating the quality of the digital read signal based on the shaped digital read signal and the binarized signal. If the quality of the read signal is calculated by a PRML method in which a number of zero-cross portions are included in a merging path of a minimum difference metric, the quality is calculated by using only a state transition pattern in which only one zero-cross portion is included in a merging path of a non-minimum difference metric.
    Type: Grant
    Filed: August 11, 2011
    Date of Patent: August 28, 2012
    Assignee: Panasonic Corporation
    Inventors: Harumitsu Miyashita, Kohei Nakata
  • Patent number: 8248902
    Abstract: A reproduction signal evaluation unit includes a pattern detection section for extracting, from a binary signal, a specific state transition pattern which has a possibility of causing a bit error; a differential metric computing section for computing a differential metric based on the binary signal of the extracted state transition pattern; an error computing section for computing an error rate predicted based on an integration value that is integrated by an integration section, a count value that is counted by a pattern count section, an integration value that is integrated by another integration section, and a count value that is counted by another pattern count section, and a standard deviation computing section for computing a standard deviation based on the computed error rate.
    Type: Grant
    Filed: February 2, 2010
    Date of Patent: August 21, 2012
    Assignees: Panasonic Corporation, Sony Corporation
    Inventors: Harumitsu Miyashita, Yasumori Hino, Junya Shiraishi, Shoei Kobayashi
  • Patent number: 8248903
    Abstract: An apparatus for improving decoding accuracy of an equalized signal having a direct current (DC) level obtained from an optical disk is provided. A Viterbi decoder is configured to decode the equalized signal and output a Viterbi-decoded signal. A DC controller is configured to adjust the DC level of the equalized signal such that the equalized signal with the adjusted DC level is decoded.
    Type: Grant
    Filed: April 21, 2010
    Date of Patent: August 21, 2012
    Assignee: Mediatek Inc.
    Inventors: Chih-Ching Yu, Yu-Hsuan Lin
  • Patent number: 8194801
    Abstract: A method for communication includes receiving a spatially-multiplexed signal using multiple receivers to produce multiple respective received signals. The spatially-multiplexed signal includes multiple simultaneously-transmitted symbols, which are selected from respective sets of constellation symbols, each constellation symbol representing a respective set of values of a group of data bits. Combinations of the constellation symbols are traversed iteratively. Each combination includes one constellation symbol from each of the sets of the constellation symbols and represents N data bits. The traversed combinations are searched for a combination that matches the received signals. During traversal of the combinations, at least 2N measures of likelihood regarding the values of the data bits represented by each traversed combination are accumulated. The accumulated measures of likelihood are processed to produce soft bit metrics.
    Type: Grant
    Filed: September 21, 2011
    Date of Patent: June 5, 2012
    Assignee: Altair Semiconductor Ltd.
    Inventors: Yigal Bitran, Itay Lusky, Ariel Yagil
  • Patent number: 8188795
    Abstract: In a synchronous reproduction signal processor, when a phase error between reproduction data and a clock is repeatedly detected such that a clock synchronized with a reproduction signal is generated based on the phase error, a filtering process unit (34) performs a filtering process which performs a weighed addition with respect to a phase error series prior to the current time from a phase error calculation unit (33) using, e.g., a FIR filter with a plurality of taps so as to generate a reference value under reduced influence of noise mixed in the phase error series by feedback correction. A cross detection unit (32) detects the timing with which the sampled reproduction data crosses the reference value generated by the filtering process unit (34). This allows effective use of the dynamic range of the feedbacked reference value without limiting it, and simultaneously achieves the enhancement of noise immunity.
    Type: Grant
    Filed: July 8, 2008
    Date of Patent: May 29, 2012
    Assignee: Panasonic Corporation
    Inventors: Kouji Okamoto, Kouhei Nakata
  • Patent number: 8189443
    Abstract: A signal quality evaluation method is provided that can objectively evaluate signal quality regardless of a PRML detection method used. The signal quality evaluation method is used when recording and reading is performed by irradiating a medium with a laser beam having a wavelength of ? through an objective lens having a numerical aperture of NA. In the signal quality evaluation method, information of the difference between an ideal signal recoded in the medium and a real signal obtained by irradiating the medium with the laser beam is statistically analyzed for each signal level of the ideal signal. The evaluation of the quality of the real signal is made using the statistics obtained by the statistical analysis.
    Type: Grant
    Filed: May 5, 2008
    Date of Patent: May 29, 2012
    Assignee: TDK Corporation
    Inventors: Takashi Kikukawa, Hidetake Itoh
  • Patent number: 8189445
    Abstract: The present invention relates to an optical disk reproducing apparatus, and provides a technology capable of supporting even a situation in which a reproduction signal characteristic is changed due to a factor other than recording density of an optical disk by using PRML of different constrained length and capable of improving reading accuracy. The optical disk reproducing apparatus includes a PRML circuit of first constrained length (for example, 4) and a PRML circuit of second constrained length (for example, 5). Equalization error values obtained during calculation of equalization learning in respective circuits are compared with each other in a determination circuit. Switching control of a switch is performed so that an output of one of the PRML circuits having a smaller equalization error value is selected.
    Type: Grant
    Filed: June 1, 2011
    Date of Patent: May 29, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Yusuke Nakamura, Masakazu Ikeda
  • Patent number: 8189444
    Abstract: This invention allows super-resolution reproduction with which a better bER value is attainable, when information is recorded by a random pattern including a mark length not longer than a resolution limit, by use of a highly versatile signal decoding method. Information is recorded as marks and spaces coded by RLL(1, 7) modulation, which each of the marks and spaces have one of a plurality of lengths, and 2T marks and 2T spaces of the marks and spaces being formed are shorter than 0.12 ?m. An information recording layer (20) includes a reproduction film (21) and a reflective film (22) which are provided in this order from a side from which reproducing light is incident, which reproduction film is made of (i) zinc oxide, (ii) strontium titanate, (iii) titanium oxide, (iv) cerium oxide, or (v) a material including at least one of the (i) through (iv), and which reflective film is made of tantalum or titanium.
    Type: Grant
    Filed: May 30, 2008
    Date of Patent: May 29, 2012
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Go Mori, Hirohisa Yamada, Masaki Yamamoto, Yasuhiro Harada, Hideharu Tajima, Shigemi Maeda, Yoshiteru Murakami
  • Patent number: 8174949
    Abstract: Various embodiments of the present invention provide systems, methods and media formats for processing user data derived from a storage medium. As an example, a system is described that includes a storage medium with a series of data. The series of data includes a servo data and a user data region. The user data region includes a first synchronization pattern and a second synchronization pattern located a distance from the first synchronization pattern. A storage buffer is provided that is operable to receive at least a portion of the series of data. A retiming circuit calculates an initial phase offset and frequency offset for a defined bit within the storage buffer using a first location of the first synchronization pattern and a second location of the second synchronization pattern. An error correction loop circuit re-samples the series of data from the storage buffer based at least in part on the initial phase offset and a frequency offset.
    Type: Grant
    Filed: July 2, 2009
    Date of Patent: May 8, 2012
    Assignee: LSI Corporation
    Inventor: Nayak Ratnakar Aravind
  • Patent number: 8169871
    Abstract: Provided herein are hybrid laser diode drivers (LDDs) that drive a laser diode in response to receiving enable signals from a controller. In accordance with specific embodiments, a hybrid LDD includes a read channel to selectively output a read current, one or more write channel each to selectively output a write current, and an oscillator channel to selectively output an oscillator current. Additionally, in specific embodiments the hybrid LDD includes a state machine that receives the enable signals from the controller, and based on the enable signals, controls timing of the currents output by the read, write and oscillator channels.
    Type: Grant
    Filed: October 4, 2010
    Date of Patent: May 1, 2012
    Assignee: Intersil Americas Inc.
    Inventors: Theodore D. Rees, Akihiro Asada
  • Patent number: 8165007
    Abstract: An information detection device includes an equalizer that equalizes the readout signal to a PR channel having equalization target levels of four or more values, and a Viterbi detector. The Viterbi detector generates branch metrics with the equalization target levels as reference levels to determine recording data from an output of the equalizer. The Viterbi detector has a mode of generating the branch metrics and determining the recording data by limiting at least one out of a maximum value and a minimum value of the equalization target levels.
    Type: Grant
    Filed: November 9, 2010
    Date of Patent: April 24, 2012
    Assignee: Renesas Electronics Corporation
    Inventor: Hiromi Honma
  • Patent number: 8159922
    Abstract: A high-density optical disc such as a high density-digital versatile disc (HD-DVD) or Blu-ray disc, and a method for reproducing or recording data of the high-density optical disc. The high-density optical disc includes a lead-in area, a data area and a lead-out area. The lead-in area has control information. A minimum mark or space length of the control information recorded in the lead-in area is longer than that of data recorded in the data area. The control information of the lead-in area is copied to the lead-out area. On the basis of the data reproduction or recording method, an optical disc device can correctly read and confirm the control information from the high-density optical disc, minimize the interference between a mark and space in high-density recording data, reduce the effects of scratches or dust on the disc, and efficiently prevent an erroneous data reproduction or recording operation.
    Type: Grant
    Filed: July 25, 2007
    Date of Patent: April 17, 2012
    Assignee: LG Electronics Inc.
    Inventors: Kyung Chan Park, Young Kuk Kim
  • Patent number: 8159918
    Abstract: A reproduction signal evaluation method evaluates the quality of a reproduction signal reproduced from an information recording medium based on a binary signal generated from the reproduction signal using a PRML signal processing system. The method includes a pattern extraction step of extracting, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step of computing a differential metric based on the binary signal; an extraction step of extracting the differential metric which is not greater than a predetermined signal processing threshold; a step of determining a mean value of the differential metrics which are not greater than the signal processing threshold and extracted in the extraction step; a standard deviation computing step of determining a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step of evaluating a quality of the reproduction signal using the standard deviation.
    Type: Grant
    Filed: July 1, 2009
    Date of Patent: April 17, 2012
    Assignees: Panasonic Corporation, Sony Corporation
    Inventors: Harumitsu Miyashita, Yasumori Hino, Junya Shiraishi, Shoei Kobayashi