OKAMOTO Yoshihiro

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Name
OKAMOTO Yoshihiro
Affiliation
Ehime University
Section
Graduate School of Science and Engineering Electrical and Electronic Engineering and Computer Science
Job title
Professor

Research Areas

 
 

Education

 
 
 - 
1985
Graduate School, Division of Engineering, Ehime University
 
 
 - 
1983
Faculty of Engineering, Ehime University
 

Published Papers

 
M. Nishikawa, Y. Nakamura, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoka
IEEE Transactions on Magnetics      May 2018
IEEE In recent years, shingled magnetic recording (SMR) has attracted attention as a new recording system of the hard disk drives. Although SMR can realize narrow track by overwriting data track like tile roofing, it has remarkable performance det...
Y. Nakamura, M. Nishikawa, H. Osawa, Y. Okamoto, T. Kanao, R. Sato
IEEE Transactions on Magnetics      May 2018
IEEE The 3-D magnetic recording using microwave-assisted magnetic recording has been proposed as one of the prospective recording technologies which uses a spin-torque oscillator (STO) as a reading sensor as well as a write-assisting device. In th...
Y. Nakamura, M. Nishikawa, H. Osawa, Y. Okamoto, T. Kanao, R. Sato
AIP Advances   8(5)    May 2018   [Refereed]
R. Suzuto, Y. Nakamura, M. Nishikawa, H. Osawa, Y. Okamoto, Y. KanaiH. Muraoka
IEEE Transactions on Magnetics      Nov 2017   [Refereed]
T. Kondoh, Y. Nakamura, M. Nishikawa, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoka
IEEE Transactions on Magnetics      Nov 2017   [Refereed]
Y. Nakamura, R. Suzuto, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoka
AIP Advances   7    May 2017
© 2017 Author(s). Two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) draws attention as a next generation technology to increase the recording density in hard disk drive (HDD). It is shown that the two-dimensional finit...
W. Busyatras, C. Warisarn, Y. Okamoto, Y. Nakamura, L. M.M. Myint, P. Supnithi, P. Kovintavewat
AIP Advances   7    May 2017
� 2016 Author(s). This paper proposes a utilization of multiple read heads to predict and correct a track mis-registration (TMR) in bit-patterned media recording (BPMR) based on the readback signals. We propose to use the signal energy ratio bet...
John R. Barry, Bane Vasic, Mehrdad Khatami, Mohsen Bahrami, Yasuaki Nakamura, Yoshihiro Okamoto, Yasushi Kanai
IEEE Transactions on Magnetics   52    Feb 2016   [Refereed][Invited]
© 1965-2012 IEEE. The move from traditional single-track magnetic recording to two-dimensional magnetic recording (TDMR) with squeezed tracks and multiple readers opens up new design degrees of freedom beyond the track pitch and bit-aspect ratio, ...
R. Suzutou, Y. Nakamura, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoka
IEEE Transactions on Magnetics   51    Nov 2015   [Refereed]
© 1965-2012 IEEE. 2-D magnetic recording (TDMR) exploits 2-D signal processing using the waveforms reproduced by array head from the intended and adjacent tracks to mitigate the effects of intertrack interference. However, an array head has the is...
Atsushi Musha, Atsushi Musha, Osamu Shimizu, Yasuaki Nakamura, Yoshihiro Okamoto
IEEE Transactions on Magnetics   51    Nov 2015
© 1965-2012 IEEE. A timing recovery method for a high-density tape storage system is studied in this paper. Since tape systems suffer from large speed variations compared with disk systems, the design of a stable timing recovery scheme that can op...
S. Kawamura, Y. Okamoto, Y. Nakamura, H. Osawa, Y. Kanai, H. Muraoaka
Journal of Applied Physics   117    May 2015
© 2015 AIP Publishing LLC. Two-dimensional magnetic recording is affected by the inter-track interference (ITI) from the adjacent tracks. We investigate the improvement of partial response maximum likelihood (PRML) systems with signal dependent no...
Y. Nakamura, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoaka
Journal of Applied Physics   117    May 2015
© 2015 AIP Publishing LLC. The two-dimensional magnetic recording (TDMR) exploits two-dimensional signal processing using the neighboring read-back waveforms. We allocate dual readers for the intended tracks and evaluate the effects of head skew a...
Bane Vasic, Mehrdad Khatami, Yasuaki Nakamura, Yoshihiro Okamoto, Yasushi Kanai, John R. Barry, Steven W. McLaughlin, Elnaz Banan Sadeghian
IEEE Transactions on Magnetics   51    Apr 2015
© 1965-2012 IEEE. This paper presents the results of a comprehensive study of the shingled writing process and various signal processing and data detection approaches applied to the readback waveforms. The recording simulations include realistic h...
Yasuaki Nakamura, Naoki Fujimoto, Yoshihiro Okamoto, Hisashi Osawa, Hiroaki Muraoka
IEEE Transactions on Magnetics   50    Nov 2014
© 1965-2012 IEEE. The two-dimensional magnetic recording (TDMR) by shingled magnetic recording needs two-dimensional (TD) signal processing using the multiple read-back waveforms. In this paper, to allocate dual readers (reader 1 and 2) for the in...
Hirofumi Nobuhara, Yoshihiro Okamoto, Masato Yamashita, Yasuaki Nakamura, Hisashi Osawa, Hiroaki Muraoka
Journal of Applied Physics   115    May 2014
In this paper, we investigate the influence of the writing and reading intertrack interferences (ITIs) in terms of bit aspect ratio (BAR) in shingled magnetic recording by computer simulation using a read/write model which consists of a writing pr...
Masato Yamashita,Yoshihiro Okamoto,Yasuaki Nakamura,Hisashi Osawa,Simon J. Greaves,Hiroaki Muraoka
IEICE Transactions   96-C(12) 1504-1507   Dec 2013   [Refereed]
The previously-proposed model of the writing process in TDMR is modified based on the Stoner-Wohlfarth reversal mechanism. The BER performance for a neuro-ITI canceller is obtained via computer simulation using the R/W channel model based on the w...
Yasuaki Nakamura,Yoshihiro Okamoto,Hisashi Osawa,Hajime Aoi,Hiroaki Muraoka
IEICE Transactions   96-C(12) 1497-1503   Dec 2013   [Refereed]
Bit-patterned medium (BPM) is one of the promising approaches for ultra-high density magnetic recording systems. However, BPM requires precise write synchronization, and exhibits write-errors due to insufficient write field gradient, medium switch...
Masato Yamashita, Yoshihiro Okamoto, Yasuaki Nakamura, Hisashi Osawa, Hiroaki Muraoka
IEEE Transactions on Magnetics   49 3810-3813   Aug 2013
A neuro intertrack interference canceller (neuro-ITIC) is proposed to diminish the influences of ITI and jitter-like medium noise for two-dimensional magnetic recording (TDMR) by shingled magnetic recording. The bit error rate (BER) performance of...
Yasuaki Nakamura, Jun Ueda, Yoshihiro Okamoto, Hisashi Osawa, Hiroaki Muraoka
IEEE Transactions on Magnetics   49 3791-3794   Aug 2013
Two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) is one of the most promising technologies for realizing high areal densities. The read/write (R/W) channel model based on a discrete Voronoi model is relatively easily ...
Hirofumi Nobuhara, Yoshihiro Okamoto, Yasuaki Nakamura, Kazuki Takada, Masato Yamashita, Hisashi Osawa, Hiroaki Muraoka
IEEE Transactions on Magnetics   49 3814-3817   Aug 2013
In this paper, the influence of the intertrack interference (ITI) at writing in shingled magnetic recording (SMR) as well as at reading is examined using a read/write model based on recording on a medium composed of discrete Voronoi diagram by a t...
Yasuaki Nakamura, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka
IEEE Transactions on Magnetics   49 662-667   Feb 2013
A 2-D magnetic recording (TDMR) by shingled magnetic recording (SMR) is one of the most promising technologies for realizing ultra-high areal densities. We have developed the discretized granular medium model with nonmagnetic grain boundaries and ...
Masato Yamashita, Yoshihiro Okamoto, Yasuaki Nakamura, Hisashi Osawa, Kenji Miura, Simon J. Greaves, Hajime Aoi, Yasushi Kanai, Hiroaki Muraoka
IEEE Transactions on Magnetics   48 4586-4589   Oct 2012
Modeling of a simple writing process considering intergranular exchange fields and magnetostatic interaction fields between grains is studied for two-dimensional magnetic recording (TDMR). A new designing method of a two-dimensional neural network...
Yasuaki Nakamura, Yasuhisa Bandai, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka
IEEE Transactions on Magnetics   48 4602-4605   Oct 2012
It is expected for the nonbinary low-density parity-check (LDPC) coding and iterative decoding system to introduce the turbo equalization in order to enhance the error correction ability in the bit-patterned medium (BPM) R/W channel. In this paper...
Masato Yamashita, Yoshihiro Okamoto, Yasuaki Nakamura, Hisashi Osawa, Kenji Miura, S. Greaves, H. Aoi, Y. Kanai, Hiroaki Muraoka
Journal of Applied Physics   111    Apr 2012
A simple writing process considering magnetic clusters due to exchange coupling between grains is studied for two-dimensional magnetic recording. The bit error rate (BER) performance of a low-density parity-check coding and iterative decoding syst...
Yasuaki Nakamura,Yoshihiro Okamoto,Hisashi Osawa,Hajime Aoi,Hiroaki Muraoka
Proceedings of the International Symposium on Information Theory and its Applications, ISITA 2012, Honolulu, HI, USA, October 28-31, 2012   121-124   2012   [Refereed]
Yasuaki Nakamura, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka
Physics Procedia   16 88-93   Dec 2011
We evaluate the performance of the write-margin for the low-density parity-check (LDPC) coding and iterative decoding system in the bit-patterned media (BPM) R/W channel affected by the write-head field gradient, the media switching field distribu...
Hisashi Osawa, Masayuki Kawae, Yoshihiro Okamoto, Yasuaki Nakamura, Hiroaki Muraoka
Physics Procedia   16 75-82   Dec 2011
The neural network equalizer (NNE) for the generalized partial response maximum likelihood (GPRML) system with a postprocessor in perpendicular magnetic recording is studied. First, a new designing method of NNE is proposed for suppressing frequen...
Kazumasa Ozaki, Yoshihiro Okamoto, Yasuaki Nakamura, Hisashi Osawa, Hiroki Muraoka
Physics Procedia   16 83-87   Dec 2011
Shingled magnetic recording attracts much attention as a new recording system for hard disk drive to make the narrower track than the writer-track-width. However, the issue for reading by a wider reader than the track width on the media remains, a...
Masato Yamashita, Hisashi Osawa, Yoshihiro Okamoto, Yasuaki Nakamura, Yoshio Suzuki, Kenji Miura, Hiroaki Muraoka
IEEE Transactions on Magnetics   47 3558-3561   Oct 2011
An accurate medium modeling method of discretized granular medium with non-magnetic grain boundaries using a discrete Voronoi diagram is proposed for two-dimensional magnetic recording. A simple closed-form representation of a double-shielded read...
Yoshihiro Okamoto, Kazumasa Ozaki, Masato Yamashita, Yasuaki Nakamura, Hisashi Osawa, Hiroaki Muraoka
IEEE Transactions on Magnetics   47 3570-3573   Oct 2011
The performance of an iterative decoding system is evaluated in shingled magnetic recording (SMR). The medium model is made by a discrete Voronoi model, and the 2-D sensitivity function of reader is used to obtain the reproducing waveform. As the ...
Yasuaki Nakamura, Yasuhisa Bandai, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka
IEEE Transactions on Magnetics   47 3566-3569   Oct 2011
In this paper, the iterative decoding system using the nonbinary low-density parity-check (LDPC) code is studied in the magnetic recording system using a bit-patterned media (BPM) R/W channel affected by the write head field gradient, the media sw...
OSAWA Hisashi, KAWAE Masayuki, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
The transactions of the Institute of Electronics, Information and Communication Engineers. C   94(9) 261-268   Sep 2011
垂直磁気記録再生系におけるポストプロセッサを伴うPRML(partial response maximum likelihood)方式のためのニューラルネットワーク等化器について検討している.まず,高レベルの識別点雑音の発生を抑圧するニューラルネットワーク等化器(NNE)の設計法を提案する.本手法では,分散遺伝的アルゴリズムと誤差逆伝搬法を組み合わせたハイブリット分散遺伝的アルゴリズムに用いる適応度に識別点雑音の頻度分布形状を調節する項を導入することにより高レベルの識別点雑音の抑圧とNNE...
Hisashi Osawa, Shogo Natsui, Yoshihiro Okamoto, Yasuaki Nakamura
Japanese Journal of Applied Physics   50    Sep 2011
The neural network equalizer (NNE) matched to recording code is proposed to reduce the influence of interpixel interference in holographic data storage (HDS). A searching method is proposed to proceed simultaneously with the search of a conversion...
Yupin Suppakhun,Pornchai Supnithi,Yoshihiro Okamoto,Yasuaki Nakamura,Hisashi Osawa
IEICE Transactions   94-C(9) 1472-1478   Sep 2011   [Refereed]
In this paper, we propose a new method to estimate and effectively reduce the effect of thermal asperity (TA) in the perpendicular magnetic recording (PMR) channels with the state trellis. The TA is estimated from the state trellis, then its avera...
Osawa Hisashi, Yamashita Masato, Okamoto Yoshihiro, Nakamura Yasuaki
Jpn J Appl Phys   49(8) 08KD10-08KD10-3   Aug 2010
The neuro-interpolator (NI) integrating the interpolator with neural network equalizer is proposed to reduce the influence of interpixel interference in holographic data storage. The simplification of NI is performed by using a hybrid genetic algo...
Hisashi Osawa, Masato Yamashita, Masato Yamashita, Yoshihiro Okamoto, Yoshihiro Okamoto, Yasuaki Nakamura, Yasuaki Nakamura
Japanese Journal of Applied Physics   49(8,Issue 3) 1-8   Aug 2010
The neuro-interpolator (NI) integrating the interpolator with neural network equalizer is proposed to reduce the influence of interpixel interference in holographic data storage. The simplification of NI is performed by using a hybrid genetic algo...
OKAMOTO Yoshihiro, BUSHISUE Taku, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
The transactions of the Institute of Electronics, Information and Communication Engineers. C   93(4) 128-137   Apr 2010
本論文では,NLTS(nonlinear transition shift)を伴う垂直磁気記録再生系において,誤りパターンとパリティ検査符号を組み合わせたポストプロセッサを提案し,その性能評価を行っている.まず,記録補償器を備えたPRML方式の記録再生系について述べ,NLTS,記録補償が性能に与える影響とその誤りの特徴について述べている.次いで,その誤りの特徴とパリティ検査符号を組み合わせたポストプロセッサについて述べ,ポストプロセッサを用いた方式の性能比較を行った.その結果,提案した方式...
OSAWA Hisashi, HINO Masaya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
The transactions of the Institute of Electronics, Information and Communication Engineers. C   93(4) 119-127   Apr 2010
本論文では,サーマルディケイを伴う垂直磁気記録再生系におけるGPRML(Generalized Partial Response Maximum Likelihood)方式のためのニューラルネットワーク等化器の簡単化について検討している.まず,雑音の白色化機能を備える簡単化ニューラルネットワーク等化器(NNE)の設計法を提案している.本手法は,ハイブリッド遺伝的アルゴリズムとレビンソン・ダービンアルゴリズムの交互繰返し学習により得られたNNEにおいて,寄与の小さい結合荷重をもつ結合を間引く...
Yasuaki Nakamura, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka
IEEE Transactions on Magnetics   45(10) 3753-3756   Oct 2009
In this paper, low-density parity-check (LDPC) coding and iterative decoding system is studied in the magnetic recording system using a bit-patterned medium (BPM). The magnetic recording system using BPM has a serious problem of requiring precise ...
Y. Nakamura, Y. Okamoto, H. Osawa, H. Muraoka, H. Aoi
2008 International Symposium on Information Theory and its Applications, ISITA2008      Dec 2008
In this paper, a burst detection scheme using a parity check matrix of LDPC code is described for the perpendicular magnetic recording using a bit-pattered medium. It is assumed that the burst-like bit-flipping occurs due to missing the write sync...
SHINOHARA Nobuhiko, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MIURA Kenji, MURAOKA Hiroaki, NAKAMURA Yoshihisa
The transactions of the Institute of Electronics, Information and Communication Engineers. C   91(12) 772-779   Dec 2008
サーマルディケイを伴う垂直磁気記録に対するGPRML (Generalized Partial Response Maximum Likelihood)方式の性能評価を行っている.熱安定性の異なる三つのCoPtCr-SiO_2垂直磁気記録媒体の再生波形振幅の経時変化特性にフィットする近似式を求めた.この近似式より,ユーザデンシティを変えた場合の実測では得がたい長期間後の再生波形減衰量を求めることができる.これより, RLL (Run-Length-Limited)符号として128/130(...
Hisashi Osawa, Masaya Hino, Nobuhiko Shinohara, Yoshihiro Okamoto, Yasuaki Nakamura, Hiroaki Muraoka
IEEE Transactions on Magnetics   44(11,Pt.2) 3777-3780   Nov 2008
A new design method of the simplified neural network equalizer (NNE) with the noise whitening function for a generalized partial response (GPR) channel is proposed. The long-term bit error rate performance of GPR class-I maximum likelihood (GPR1ML...
Yasuaki Nakamura, Mitsuhiro Nishimura, Yoshihiro Okamoto, Hisashi Osawa, Hiroaki Muraoka
IEEE Transactions on Magnetics   44(11,Pt.2) 3773-3776   Nov 2008
In this paper, a new burst detection method using the check matrix of low-density parity-check (LDPC) code is proposed. The burst detection for the bit flipping burst-like signal degradation which the conventional burst detection using a reproduci...
N. Shinohara, H. Osawa, Y. Okamoto, Y. Nakamura, K. Miura, H. Muraoka, Y. Nakamura
Journal of Magnetism and Magnetic Materials   320(22) 3136-3139   Nov 2008
The bit-error rate (BER) performance of the generalized partial response maximum likelihood with autoregressive (GPRML-AR) channel model system in perpendicular magnetic recording (PMR) channel with thermal decay is obtained. The 128/130(0,16/8) r...
Y. Kurihara, Y. Takeda, Y. Takaishi, Y. Koizumi, H. Osawa, M. Z. Ahmed, Y. Okamoto
Journal of Magnetism and Magnetic Materials   320(22) 3140-3143   Nov 2008
In this paper, we study not only the new constructive inter-track interference (CITI) code based on the equalized level but also Viterbi detection algorithm taking into account the ITI from adjacent tracks for the perpendicular magnetic recording ...
Y. Okamoto, T. Bushisue, Y. Kurihara, Y. Nakamura, H. Osawa, H. Muraoka, Y. Nakamura
Journal of Magnetism and Magnetic Materials   320(22) 3192-3195   Nov 2008
Nonlinear transition shift (NLTS) influences the performance of PRML channels in perpendicular magnetic recording. For NLTS, it is thought that write pre-compensation is useful to write the transition at the intended position. In this paper, we st...
Y. Nakamura, M. Nishimura, Y. Okamoto, H. Osawa, H. Aoi, H. Muraoka, Y. Nakamura
Journal of Magnetism and Magnetic Materials   320(22) 3132-3135   Nov 2008
In this paper, a low-density parity check (LDPC) coding and iterative decoding system is studied in perpendicular magnetic recording (PMR) with a bit-patterned medium. We propose the efficient iterative decoding algorithm attenuating reliability i...
NAKAMURA Yasuaki, NISHIMURA Mitsuhiro, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki, NAKAMURA Yoshihisa
The Institute of Electronics, Information and Communication EngineersIEICE TRANSACTIONS on Electronics   91(7) 378-389   Jul 2008
本論文では,バーストを伴う垂直磁気記録再生系において,4096バイト/セクタのロングセクタを想定してLDPC符号の性能評価を行っている.まず,バースト検出器を適用したLDPC符号化・繰返し復号化方式の記録再生系,バースト検出器,及びバースト誤りによる誤り伝搬を抑制するための繰返し復号器について述べている.次いで,計算機シミュレーションにより所定のデータを誤りなく復号するための所要SN比とバースト長の関係を求め,バースト情報を用いたLDPC符号化・繰返し復号化方式とRS符号を用いた消失誤り訂...
NAKAMURA Yasuaki, NAKASHITA Shin, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki, NAKAMURA Yoshihisa
The Institute of Electronics, Information and Communication EngineersIEICE TRANSACTIONS on Electronics   90(5) 437-446   May 2007
本論文では,バーストを伴う垂直磁気記録再生系において,LDPC符号化・繰返し復号化方式の性能評価を行っている.まず,バースト検出器を適用したLDPC符号化・繰返し復号化方式の記録再生系,バースト情報を用いた復号法及びバースト検出器について述べている.次いで,計算機シミュレーションにより所定のデータ内に誤りなしとなるための所要SN比とバースト長の関係を求め,バースト検出器を用いない従来方式と比較検討を行った.その結果,SNR=23dBにおいて,従来方式は約100チャネルビットのバースト耐性し...
Hisashi Osawa, Toshimasa Shimizu, Takumi Nakaoka, Yoshihiro Okamoto, Hidetoshi Saito, Hiroaki Muraoka, Yoshihisa Nakamura
Electronics and Communications in Japan, Part II: Electronics (English translation of Denshi Tsushin Gakkai Ronbunshi)   89 19-27   Feb 2006
In this paper, we examine neural network equalization in a perpendicular magnetic recording channel with jitter medium noise and MR nonlinear distortion. First, we propose simplifying a neural network equalizer by using a hybrid genetic algorithm....
Okamoto Yoshihiro, Nakamura Yasuaki, Osawa Hisashi
Journal of Magnetics Society of Japan   29(6) 615-623   Jun 2005
Read channels such as PRML systems are key technologies in HDD design, and are often evaluated by computer simulation using a read/write channel model as well as an actual R/W channel such as a spin-stand. In PRML read-channel simulations, signica...
Okamoto Y., Kondo Y., Osawa H., Nakamura Y., Muraoka H., Nakamura Y.
Journal of Magnetics Society of Japan   29(4) 432-435   Apr 2005
It is known that jitter-like noise in perpendicular magnetic recording system is large compared with longitudinal magnetic recording system. In this paper, the recording density and the amount of magnetic transition-jitter from the signal processi...
OSAWA Hisashi, SHIMIZU Toshimasa, NAKAOKA Takumi, OKAMOTO Yoshihiro, SAITO Hidetoshi, MURAOKA Hiroaki, NAKAMURA Yoshihisa
The transactions of the Institute of Electronics, Information and Communication Engineers. C   88(4) 270-277   Apr 2005
ジッタ性媒体雑音とMR非線形ひずみを伴う垂直磁気記録チャネルにおけるニューラルネットワーク等化の検討を行っている.まず, ハイブリッドGA (Genetic Algorithm)を用いたニューラルネットワーク等化器の簡単化を提案している.次いで, 簡単化されたニューラルネットワーク等化器を備えたPR2ML方式のビット誤り率特性を求め, 従来のニューラルネットワーク等化器及びトランスバーサルフィルタ等化器の場合と比較検討した.その結果, 従来のニューラルネットワーク等化器及びトランスバーサル...
Okamoto Y., Ohtsubo J., Osawa H., Nakamura Y., Muraoka H., Nakamura Y.
Journal of Magnetics Society of Japan   29(2) 101-104   Feb 2005
In a hard disk drive (HDD), a postprocessor is used for correcting the random error in a PRML (Partial Response Maximum Likelihood) channel. However, the postprocessor needs an error-detecting code, such as a single parity check code, and the code...
MARUKAWA Shoji, KAWAMOTO Toru, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers. C   J87-C(6) 520-528   Jun 2004
ヘリカルスキャンアジマス記録では,隣接トラックからのクロストークが高密度記録を阻害する主因の一つとなっている.このクロストークは有色雑音であるので,従来のPRML(Partial Response Maximum Likelihood)方式の再生信号処理では十分な性能を得ることができなかった.本論文では,ヘリカルスキャンアジマス記録にNPML(Noise Predictive Maximum Likelihood)方式を適用した場合の性能検討を行った. NPML方式のビット誤り率とPRML...
SAITO Hidetoshi, OGAWA Takuya, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers. C   87(5) 469-479   May 2004
近年,記録符号としていくつかの誤り訂正符号を連接符号として用いる様々な記録符号化・復号化方式が検討され,その効果的な特性改善が報告されている.そこで本論文では,ディジタル通信の分野においてその高い誤り訂正能力でよく知られている高次元パリティ検査符号と,パーシャルレスポンス等化される磁気記録チャネルの組合せを統一してとらえる連接符号化・復号化方式を提案する.また,高次元パリティ検査符号の復号法として,パリティ検査線ベクトルによる誤り検出(仮判定)と,各シンボルの信頼度に対するしきい値判定(本...
Okamoto Y., Osawa H.
Journal of Magnetics Society of Japan   28(4) 490-500   Apr 2004
The remarkable increase in the recording density of hard disk drives (HDDs) owes much to the improvement of signal-processing technologies. Current commercial HDDs use longitudinal recording, and the recording density is coming close to the superp...
Osawa Hisashi, Maeto Nobuhiro, Okamoto Yoshihiro, Saito Hidetoshi, Muraoka Hiroaki, Nakamura Yoshihisa
The journal of the Institute of Image Information and Television Engineers   57(11) 1520-1525   Nov 2003
The distortion due to low frequency cutoff degrades the performance of partial response maximum likelihood(PRML) system in a perpendicular magnetic recording. This paper presents an application of guided scrambling(GS) code to PRML system as an ef...
OSAWA Hisashi, OKAMOTO Yoshihiro
The Journal of the Institute of Electronics, Information, and Communication Engineers   86(10) 780-785   Oct 2003
最近のハードディスク装置の記録密度の目覚ましい向上は信号処理技術の進展に負うところが大である将来の超高密度記録のための記録方式として垂直磁気記録方式が期待されており,そのための優れた信号処理方式の開発が望まれる。本稿では,まず,垂直磁気記録のための信号処理方式の基礎となるPRML方式について解説する。次いで,垂直磁気記録において支配的な雑音であるジッタ性媒体雑音に有効なARチャネルモテルを用いたPRML方式について述べる。更に,大幅な性能改善が期待できる繰返し符号・復号化についても紹介する
SAITO Hidetoshi, IGA Toshihiko, SHIRAKAWA Masahiro, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers. C   86(8) 952-961   Aug 2003
ハードディスク装置で用いる信号処理方式の一つとして, PRML(Partial Response Maximum Likelihood)方式がある.近年の大容量化に対する要請にこたえるために,このPRML方式に用いられる記録符号として,従来以上に高能率で符号系列間に強い制約をもつものの開発が強く求められている.そこで,本論文では,従来よく用いられている16/17(0,6/6)符号に比べて,更に高能率なラン長制約符号を提案する.そして,新たに構成するラン長制約符号の符号化・復号化則と誤り伝搬...
OSAWA Hisashi, SHINOHARA Nobuhiko, OKAMOTO Yoshihiro, SAITO Hidetoshi, MURAOKA Hiroaki, NAKAMURA Yoshihisa
The Electronics Society, The Institute of Elecronics, Information and Communication EngineersThe IEICE Transactions on Electronics (Japanese Edition)   86(5) 551-558   May 2003
ジッタ性媒体雑音を伴う垂直磁気記録再生チャネルにおけるNPML(Noise Predictive Maximum Likelihood)方式の性能評価を行っている.PR1チャネルに対するPRML方式とNPML方式のビット誤り率を計算機シミュレーションにより求め,比較検討を行った.その結果,規格化線密度が1.5におけるPRML方式に対するNPML方式のSN比改善度は,最大で約15.8dBとなることが明らかとなった.また10^<-4>のビット誤り率を達成するのに要する読出し点の所要SN比と規格...
OKAMOTO Yoshihiro, MASUNARI Noriyuki, YAMAMOTO Hirofumi, OSAWA Hisashi, SAITO Hidetoshi, MURAOKA Hiroaki, NAKAMURA Yoshihisa
The transactions of the Institute of Electronics, Information and Communication Engineers. C   86(5) 542-550   May 2003
垂直磁気記録におけるPRML方式の誤り率特性改善について検討している.ビタピ復号における入力系列の推定値演算にARチャネルモデルを適用することにより,復号器の性能向上を図っている.そこで,計算器シミュレーション,スピンスタンドを用いた記録再生実験により10_<-4>のビット誤り率を達成するのに要する読出し点の所要SN比,線記録密度を求め,従来のPRML方式との比較検討を行っている.その結果,ARチャネルモデルを適用したビタビ復号器によりPRML方式の性能改善が得られることを明らかにしている.
Y. Okamoto, N. Masunari, H. Yamamoto, H. Osawa, H. Saito, H. Muraoka, Y. Nakamura
The IEEE Magnetics SocietyIEEE Transactions on Magnetics   38(5) 2349-2351   Sep 2002
Performance improvement of partial-response maximum-likelihood (PRML) system in the perpendicular magnetic recording channel with jitter-like noise is studied. Performance of a Viterbi detector is improved by applying an autoregressive (AR) model ...
SAITO Hidetoshi, KOGURI Yoshimasa, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers. C   J85-C(3) 196-203   Mar 2002
情報ストレージ装置の高信頼性と大容量化を図るために,高密度ディジタル磁気記録に適した信号処理技術の開発が求められている.16/17MTR符号と巡回冗長検査符号を組み合わせた連接符号化方式は,軟出力ビタビアルゴリズムによる最ゆう復号と誤りパターンとのゆう度差から得られる信頼度情報を用いた消失誤り訂正を行うリスト復号を組み合わせた優れた方式として知られている.本論文では,新たに上記の連接符号化方式に軟出力双方向ビタビアルゴリズムに基づく最ゆう復号と双方向ビタビ復号の軟出力から得られる信頼度情報...
Hidetoshi Saito, Yoshihiro Okamoto, Hisashi Osawa
IEICE Transactions on Electronics   E84-C 1689-1696   Nov 2001
Turbo coding is widely known as one of effective error control coding techniques in various digital communication systems since this coding method has proposed by C. Berrou, etc in 1993. In digital magnetic recording, it has been cleared that the ...
Okamoto Yoshihiro, Kanaoka Toshikazu, Saito Hidetoshi, Osawa Hisashi, Muraoka Hiroaki, Nakamura Yoshihisa
The journal of the Institute of Image Information and Television Engineers   55(10) 1353-1358   Oct 2001
The performance of serially concatenated turbo coding systems using various RLL codes was evaluated and compared with that of PRML systems in a perpendicular magnetic recording channel. The error rates of these systems were experimentally estimate...
Akamatsu M., Okamoto Y., Saito H., Osawa H., Honda N., Ouchi K.
Journal of Magnetics Society of Japan   24(4-2) 235-238   Apr 2000
The bit-error rate (BER) performance of 16/17 (0, 6/6) coded PRML systems for a single-layered perpendicular medium was studied by conducting read/write experiments using a spinstand system. The results show that the E^3PR4ML system exhibits the b...
OSAWA Hisashi, FUJIKAWA Kazuyuki, OKAMOTO Yoshihiro, SAITO Hidetoshi
The transactions of the Institute of Electronics, Information and Communication Engineers. C   J83-C(1) 77-82   Jan 2000
パーシャルイレージャを伴う記録・再生系へのニューラルネットワークFDTS / DF方式の適用について検討を行っている.まず, パーシャルイレージャを伴う記録・再生チャネルのモデル及びニューラルネットワークFDTS / DF方式について述べている.次いで, 計算機シミュレーションによりビット誤り率を求め, 従来のFDTS / DF方式の場合との性能比較を行った.その結果, ニューラルネットワークFDTS / DF方式の場合の誤り率特性が従来のFDTS / DF方式の場合よりも良好となり, 1...
OKAMOTO Yoshihiro, ASHIKAGA Hiroshi, SAITO Hidetoshi, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers. C   83(1) 70-76   Jan 2000
MRヘッドと垂直2層膜媒体を用いた垂直磁気記録のためのPRML(Partial Response Maximum Likelihood)方式の性能評価を行っている.最近のハードディスク装置によく用いられている(1, 7)RLL符号と16 / 17(0, 6 / 6)符号を記録符号とし, トランスバーサルフィルタによる等化を仮定して計算機シミュレーションにより規格化線密度とビット誤り率10^<-4>を達成するのに要する読出し点の所要SN比の関係を求め, 比較検討した.その結果, 比較的低密度...
Hisashi Osawa, Kazuyuki Fujikawa, Yoshihiro Okamoto, Hidetoshi Saito
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers   53 1615-1619   Dec 1999
A neural network canceller has been applied to the PR4ML channel with partial erasure. First, a model of the read/write channel with partial erasure and the neural network canceller are described. Then, the bit-error rate of the PR4ML channel is e...
SAITO Hidetoshi, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers   J82-C-II(6) 346-352   Jun 1999
ディジタル磁気記録における有力な信号処理方式に挙げられるPRML方式に対する整合性の良い記録符号の一つとして, トレリス符号が考えられている. 本論文では, 集合分割法をもとにPR4, EPR4方式に整合するトレリス符号を構成する. 符号構成では, パーシャルレスポンス方式の許容する出力シンボルをもとに信号配置を定義し, 多次元ユークリッド空間上で部分集合分割し, 最良なトレリス符号を構成する. この結果, ナイキスト等化を用いたPR4及びEPR4方式に対して, 拘束長6, 7をもつ符号化...
SAITO Hidetoshi, YOKOYAMA Takanori, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers   J82-C-II(6) 337-345   Jun 1999
本論文では, 従来知られる8/10MSN符号よりも, 更に高符号化率な9/10MSN符号を新たに構成する. そして, 高密度記録において, 磁気記録再生系に大きな影響を及ぼす非線形ひずみの一種であるパーシャルイレージャを考慮したビット誤り率を計算機シミュレーションにより求め, 性能評価を行う. ここで提案する9/10MSN符号は, ルックアップテーブルのみを用いて復号できる符号語のみを集合とし, 従来の8/10MSN符号と異なって, スライディングブロック復号器を必要としない構成としている...
Ichihara K., Okamoto Y., Saito H., Osawa H.
Journal of Magnetics Society of Japan   23(4-2) 1069-1072   Apr 1999
PRML systems for perpendicular magnetic recording using a single-layer medium were studied. Reproduced waveforms at linear densities of 150 to 300 kBPI were acquired by recording and reading-back experiments using a perpendicular single-layer medi...
OKAMOTO Yoshihiro, MIYASITA Harumitsu, SAITO Hidetoshi, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers   J81-C-II(12) 924-931   Dec 1998
(1, 7)RLL符号, 8/9(0, 4/4)符号, 16/17(0, 6/6)符号の3種類の符号に対する各種PRML方式の性能について比較検討している.パーシャルイレージャのある高密度ディジタル磁気記録再生系において, PR4ML, EPR4ML, E^2PR4ML, ME^2PR4ML方式, PR(1, 1, 1, -1, -1, -1)ML, PR(1, 2, 1, -1, -2, -1)ML, PR(1, 2, 1, 0, -1, -2, -1)ML, 方式のビット誤り率を計算機...
Hisashi Osawa, Yuu Moriyama, Yoshihiro Okamoto, Hidetoshi Saito
The Institute of Image Information and Television EngineersThe Journal of the Institute of Image Information and Television Engineers   52(10) 1501-1506   Dec 1998
A seaching method using genetic algorithms is studied for the optimal tap configuration of nonuniformly spaced transversal filter in digital magnetic recording. A model of the recording/reproducing channel and the genetic algorithms are described....
OSAWA Hisashi, OKAMOTO Yoshihiro, SAITO Hidetoshi
The transactions of the Institute of Electronics, Information and Communication Engineers   J81-C-I(4) 195-214   Apr 1998
近年, ディジタル記録機器の高密度化の要望は高まる一方である.本論文では, 対象を磁気ディスク装置やディジタルVTRなどのディジタル磁気記録機器に限定し, その高密度を図るための手段としての信号処理技術について述べる.まず, その基礎となるパーシャルレスポンス方式, ビタビ復号法, PRML(Partial Response Maximum Likelihood)方式について詳述する.次いで, 長手磁気記録において最近盛んに検討されている各種信号処理方式について概観する.また, 高密度記録...
SAITO Hidetoshi, NISHIKAWA Takafumi, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers   J81-C-II(4) 447-454   Apr 1998
従来のPR4ML方式に対する8/10MSN符号は, 復号トレリスにおける準カタストロフィック系列の発生を制御できるがスライディングブロック復号器を必要とする符号構成となっていた.本論文では, 周期時変トレリス線図を用いて復号できる8/10MSN符号を新たに設計した.ここで提案する8/10MSN符号は, PR出力系列間の2乗ユークリッド距離の分布を改善し, 最小2乗自由ユークリッド距離をもつ系列の組合せを減少させることができる.また, ルックアップテーブルを参照するだけで符号系列とデータ系列...
SAITO Hidetoshi, FURUKURA Eiji, OKAMOTO Yoshihiro, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers   J81-C-II(4) 430-438   Apr 1998
ディジタル磁気記録における記録符号として, 符号化率11/12パンクチャド畳込み符号を用いたPRML方式を提案した.また, 計算機シミュレーションにより各種PRML方式に対する誤り率特性を求め, 8/9符号の場合と比較検討を行った.その結果, 本提案方式は8/9符号の場合に比べて高密度記録となるほど良好な特性を示すこと, および検討したPRML方式の中でE^2PR4ML方式が最良の性能を示し, 規格化線密度が3, ビット誤り率が10^-4において, 約3.4dBのSN比改善が得られることが...
OSAWA Hisashi, OKAMOTO Yoshihiro, SAITO Hidetoshi
The Transactions of the Institute of Electronics, Information and Communication Engineers C-I   81(4) 195-214   Apr 1998
近年, ディジタル記録機器の高密度化の要望は高まる一方である.本論文では, 対象を磁気ディスク装置やディジタルVTRなどのディジタル磁気記録機器に限定し, その高密度化を図るための手段としての信号処理技術について述べる.まず, その基礎となるパーシャルレスポンス方式, ビタビ復号法, PRML(Partial Response Maximum Likelihood)方式について詳述する.次いで, 長手磁気記録において最近盛んに検討されている各種信号処理方式について概観する.また, 高密度記...
OKAMOTO Yoshihiro, SOUMA Minoru, SAITO Hidetoshi, OSAWA Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers   J80-C-II(11) 399-406   Nov 1997
ディジタル磁気記録において, 記録符号として畳込み符号を採用し, パンクチャド手法を用いたのち2トラックに記録再生する, パンクチャド畳込み符号化PR4ML方式を提案している. また, 計算機シミュレーションによりその誤り率特性を求め, 従来のI-NRZI符号化PR4ML方式の場合と比較検討を行った. その結果, 本提案方式は, 従来方式に比べ高密度記録において良好な特性を示し, 規格化線密度K=3において, 約3.8dB少ない読出し点のSN比で10<-4>の誤り率を達成できることを明らか...
Hisashi Osawa, Makoto Okada, Kohei Wakamiya, Yoshihiro Okamoto
IEICE Transactions on Electronics   E79-C 1455-1460   Dec 1996
The performance improvement of the partial response maximum-likelihood (PRML) system for (I, 7) runlength limited (RLL) code is studied. As a new PRML system, PR(1, I, 0, -1, -I) system called modified E2PR4 (ME2PR4) followed by Viterbi detector f...
Yoshitake Kurihara, Hisashi Osawa, Yoshihiro Okamoto
IEICE Transactions on Electronics   E78-C 1567-1574   Nov 1995
Simplification of the Viterbi algorithm and the error rate performance are presented for a partial response maximum-likelihood (PRML) system employing the PR(1,1) system as a PR system for (1,7) run-length limited (RLL) code. The minimum run-lengt...
Osawa Hisashi, Saeki Isao, Okamoto Yoshihiro
The transactions of the Institute of Electronics, Information and Communication Engineers   J77-C-II(6) 254-258   Jun 1994
PR(1,1,-1,-1)とPR(1,1,0,-1,-1)方式の二つのパーシャルレスポンス方式について,ビタビ復号器入力における雑音系列の相関係数の関数として誤り率の上界を導出し,これによる理論値とシミュレーション値を比較検討している.
Osawa Hisashi, Kurihara Yoshitake, Okamoto Yoshihiro, Nishida Yasutaka, Muraoka Hiroaki, Nakamura Yoshihisa
The transactions of the Institute of Electronics, Information and Communication Engineers   J77-CII(4) 190-196   Apr 1994
複合膜主磁極形単磁極ヘッドを用いた垂直記録において,パーシャルレスポンス(PR)方式と最ゆう復号法の一種であるビタビ復号法とを組み合せたPRML(Partial Response Maximum-Likelihood)方式の誤り率特性について検討している.その際,実験により得られた孤立再生波形に対して波形近似を行い,これをもとにしてシミュレーションにより誤り率を求めている.まず,等化による雑音増大を考慮に入れて,複合膜主磁極形単磁極ヘッドの特性を利用したいくつかのPR方式の識別点SN比とビ...
Osawa Hisashi, Yasui Hironobu, Okamoto Yoshihiro
The transactions of the Institute of Electronics, Information and Communication Engineers   J76-C-2(11) 763-766   Nov 1993
ディジタル磁気記録においてトランスバーサルフィルタによりPR(1,1,0,-1,-1)方式を得るときの等化特性について検討を行っている.高域遮断による影響も考慮に入れてトランスバーサルフィルタのタップ係数を定めるこにより,等化特性の改善が得られることを示している.
Okamoto Yoshihiro, Shiraishi Kozo, Osawa Hisashi
The transactions of the Institute of Electronics, Information and Communication Engineers   76(11) 750-756   Nov 1993
優れたDCフリー符号として知られているM^2符号に対する積分検出方式において,高域ノイズを抑圧するために行う帯域制限により生ずるアイの劣化を記録波形の反転位置を制御することで補償する手法を提案している.まず,計算機シミュレーションにより描いたアイパターンからアイ開口率,タイミングマージンを求め,本手法により,改善が可能であることを示している.次いで,ビット誤り率を計算機シミュレーションから求め,補償がない場合に比べて本手法では,10^<-4>の誤り率を約2.2dB少ないSN比で達成できるこ...
Osawa Hisashi, Yamamoto Nobuya, Okamoto Yoshihiro
The transactions of the Institute of Electronics, Information and Communication Engineers   J76-C-2(9) 607-614   Sep 1993
符号語内でのシンボル"0"の最小ラン長が2となる制約をもち,PR(1,1)形の等化に適した新たなn/m符号である(4,5,6)/11符号を提案している.PR(1)等化におけるサンプリング時点をT_s/2(ここに,T_sはシンボル間隔を表す)ずらせることによって,擬似的なPR(1,1)特性が得られる.(4,5,6)/11符号に対する従来のビタビ復号法の誤り率特性のシミュレーションにより求め,良く知られた4/11符号の特性と比較している.その結果,(4,5,6)/11符号はすぐれた特性を示すこ...
Okamoto Yoshihiro, Osawa Hisashi, Takigawa kiyoshi, Ono Kazuo
The transactions of the Institute of Electronics, Information and Communication Engineers   J76-C-2(9) 615-618   Sep 1993
3B-2T符号に対して2値記録波形を割り当てる擬似的な3値記録方式を提案している.そして,PR(1,0,-1)方式における所定の誤り率を達成するのに要する読出し点SN比を求め,ACバイアスによるチャネルの線形化を仮定した場合と比較検討を行っている.
Okamoto Yoshihiro, Ohosawa Hisashi, Takigawa Kiyoshi, Ono Kazuo
The Journal of the Institute of Television Engineers of Japan   46(10) 1234-1240   Oct 1992
DC freeing of the write waveform is an important technique in digital magnetic recording. The higher the recording density is, the stronger the effect of high frequency noise becomes. We use the DC-freeing technique of write equalization to boost ...
R. Suzuto, Y. Nakamura, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoka
IEEE Transactions on Magnetics   52(7)    Jul 2016   [Refereed]

Misc

 
Nakamura Yasuaki, Suzutou Ryouta, Osawa Hisashi, Okamoto Yoshihiro, Kanai Yasushi, Muraoka Hiroaki
Proceedings of the Society Conference of IEICE   2014(2)    Sep 2014
岡本 好弘, 仲村 泰明, 大沢 寿
映像情報メディア学会技術報告 = ITE technical report   38(22) 13-18   Jun 2014
Fujimoto N., Nakamura Y., Osawa H., Okamoto Y., Muraoka H.
Proceedings of the IEICE General Conference   2014(2)    Mar 2014
Nobuhara H., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2014(2)    Mar 2014
NAKAMURA Yasuaki, YANAGITA Michita, OSAWA Hisashi, OKAMOTO Yoshihiro, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   113(102) 13-17   Jun 2013
The LDPC coding and iterative decoding system has high decoding gain, but decoding error increases by the iterative decoding in low SNR area due to error propagation. In this research, we propose a new SP decoding with an error propagation suppres...
Yamashita M., Okamoto Y., Nakamura Y., Ohsawa H., S. Greaves, むらおか H.
Proceedings of the IEICE General Conference   2013(2) "S-12"-"S-13"   Mar 2013
Embara H., Okamoto Y., Nakamura Y., Yamashita M., Ohsawa H., むらおか H.
Proceedings of the IEICE General Conference   2013(2) "S-10"-"S-11"   Mar 2013
TAKADA KAZUKI, OKAMOTO Yoshihiro, NOBUHARA Hirofumi, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   112(354) 19-24   Dec 2012
A measurement method of nonlinear transition shift (NLTS) and the write precompensation in the shingled magnetic recording (SMR) are studied. In SMR R/W channel using a discrete granular medium composed of the discrete Voronoi diagram, we measure ...
Yamashita M., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2012(2)    Aug 2012
Nobuhara H., Okamoto Y., Nakamura Y., Yamashita M., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2012(2)    Aug 2012
Ueda J., Nakamura Y., Okamoto Y., Osawa H., Aoi H., Muraoka H.
Proceedings of the Society Conference of IEICE   2012(2)    Aug 2012
NAKAMURA Yasuaki, UEDA Jun, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   112(80) 1-8   Jun 2012
The symbol-by-symbol turbo equalization for non-binary low-density parity-check (LDPC) coding system is studied in magnetic recording using the bit-patterned medium (BPM) with write-errors. In this report, we evaluated the performance of the turbo...
仲村 泰明, 上田 純, 岡本 好弘
映像情報メディア学会技術報告   36(22) 1-8   Jun 2012
Nakamura Yasuaki, Bandai Yasuhisa, Okamoto Yoshihiro, Osawa Hisashi, Aoi Hajime, Muraoka Hiroaki
Proceedings of the IEICE General Conference   2012(2) "S-10"   Mar 2012
Yamashita M., Okamoto Y., Nakamura Y., Osawa H., Miura K., Greaves S., Aoi H., Kanai Y., Muraoka H.
Proceedings of the IEICE General Conference   2012(2) "S-9"   Mar 2012
NAKAMURA Yasuaki, UEDA Jun, BANDAI Yasuhisa, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
電子情報通信学会技術研究報告. MR, 磁気記録   111(350) 21-27   Dec 2011
NAKAMURA Yasuaki, UEDA Jun, BANDAI Yasuhisa, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   111(350) 21-27   Dec 2011
Symbol-by-symbol a posteriori probability (APP) decoder for non-binary low-density parity-check (LDPC) coding and iterative decoding system in perpendicular magnetic recording channel is studied. In this report, we evaluated the performance of the...
YAMASHITA Masato, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MIURA Kenji, GREAVES Simon, AOI Hajime, KANAI Yasushi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   111(350) 7-14   Dec 2011
Modeling of writing process based on a discrete Voronoi model is studied for two-dimensional magnetic recording (TDMR). This is a simple but accurate model considering the influence of write head field gradient, media switching field distribution,...
YAMASHITA Masato, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MIURA Kenji, GREAVES Simon, AOI Hajime, KANAI Yasushi, MURAOKA Hiroaki
電子情報通信学会技術研究報告. MR, 磁気記録   111(350) 7-14   Dec 2011
山下 正人, 岡本 好弘, 仲村 泰明
映像情報メディア学会技術報告   35(53) 7-14   Dec 2011
Osawa Hisashi, Natsui Shogo, Okamoto Yoshihiro, Nakamura Yasuaki
Jpn J Appl Phys   50(9) 09MB05-09MB05-4   Sep 2011
The neural network equalizer (NNE) matched to recording code is proposed to reduce the influence of interpixel interference in holographic data storage (HDS). A searching method is proposed to proceed simultaneously with the search of a conversion...
Bandai Y., Nakamura Y., Okamoto Y., Osawa H., Aoi H., Muraoka H.
Proceedings of the Society Conference of IEICE   2011(2)    Aug 2011
Yamashita M., Okamoto Y., Nakamura Y., Osawa H., Miura K., Greaves S., Aoi H., Kanai Y., Muraoka H.
Proceedings of the Society Conference of IEICE   2011(2)    Aug 2011
Nagai H., Yamashita M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the Society Conference of IEICE   2011(2)    Aug 2011
NAKAMURA Yasuaki, BANDAI Yasuhisa, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hazime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   111(140) 43-48   Jul 2011
The write errors are caused by the write head field gradient, the media switching field distribution (SFD), the demagnetization field from adjacent islands and the island position deviation in the R/W channel using the bit-patterned media (BPM). I...
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MIURA Kenji, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   111(140) 27-34   Jul 2011
Modeling of granular medium with non-magnetic grain boundaries using a discrete Voronoi diagram is proposed for two-dimensional magnetic recording. Simplified two-dimensional neural network equalizer (2D-NNE) is also proposed to mitigate the influ...
仲村 泰明, 萬代 康久, 岡本 好弘
ITE technical report   35(27) 43-48   Jul 2011
山下 正人, 大沢 寿, 岡本 好弘
ITE technical report   35(27) 27-34   Jul 2011
Yamashita M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the IEICE General Conference   2011(2) "S-12"   Feb 2011
Yamashita J., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2011(2)    Feb 2011
Morikawa T., Nakamura Y., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2011(2)    Feb 2011
Okinaka K., Nakamura Y., Okamoto Y., Osawa H.
Proceedings of the IEICE General Conference   2011(2)    Feb 2011
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, SUZUKI Yoshio, MIURA Kenji, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   110(329) 31-38   Dec 2010
Read/write channel modeling using a discrete Voronoi diagram is studied for two-dimensional magnetic recording. The simple closed-form representation of reader sensitivity function with fitting parameters given by linear combinations of geometry p...
山下 正人, 大沢 寿, 岡本 好弘
ITE technical report   34(53) 31-38   Dec 2010
OSAWA Hisashi, KAWAE Masayuki, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   110(225) 51-57   Oct 2010
The neural network equalization for LDPC coding and iterative decoding system in perpendicular magnetic recording is studied. First, a design method of neural network equalizer (NNE) is proposed for LDPC coding and iterative decoding system. In ou...
大沢 寿, 河江 政幸, 岡本 好弘
ITE technical report   34(39) 51-57   Oct 2010
NATSUI Shogo, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki
Proceedings of the ... ITE annual convention   2010(2010) 18-4-1-"18-4-2"   Aug 2010
A simplification method of neural network equalizer(NNE) fitting in the recording code is studied in holographic data storage. A 40 percent reduction in the number of connections in the NNE is attained without performance degradation.
OKINAKA Kazutaka, NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi
Proceedings of the ... ITE annual convention   2010(2010) 18-1-1-"18-1-2"   Aug 2010
The performances of the PRML systems are evaluated in a two-photon absorption recording channel model. The results show that the PR(1,2,2,2,1)ML system has the better performance compared with the PR(1,2,2,1)ML system.
KURIHARA Y., MAEDA Y., MATSUMOTO M., NAGASHIMA K., OSAWA H., OKAMOTO Y.
Proceedings of the ... ITE annual convention   2010(2010) 17-2-1-"17-2-2"   Aug 2010
In 2008, we investigated the PR2ML system for two track perpendicular recording model where the recording code was the constructive intertrack interference (CITI) code which converts the six user bits into a pair of four channel bits. In this pape...
TERASHIMA Taiki, NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
Proceedings of the ... ITE annual convention   2010(2010) 17-1-1-"17-1-2"   Aug 2010
The RS code is usually decoded using a hard-decision decoding algorithm in HDD. In this study, the soft-decision iterative decoding for the RS code is studied as the sub-optimal decoding in the perpendicular magnetic recording channel.
Kawae M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the Society Conference of IEICE   2010(2)    Aug 2010
YAMASHITA Jyunya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
ITE Technical Report   34(20) 73-78   Jun 2010
The iterative decoder is composed of APP (a posteriori probability) decoder using the characteristics of PR (partial response) channel and SP (sum-product) decoder using the check matrix of LDPC (low density parity check) code. As the jitter-like ...
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki
ITE Technical Report   34(20) 67-71   Jun 2010
The neuro-interpolator (NI) integrating an interpolator with a neural network equalizer in holographic data storage is proposed to reduce the influence of interpixel interference due to the aperture restriction which limits the effective recording...
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
ITE Technical Report   34(20) 21-26   Jun 2010
In this report, we evaluate the performance of the write-margin for the low-density parity-check (LDPC) coding and iterative decoding system in the bit-patterned media (BPM) R/W channel affected by the write-head field gradient, the media switchin...
YAMASHITA Jyunya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   110(68) 73-78   Jun 2010
The iterative decoder is composed of APP(a posteriori probability)decoder using the characteristics of PR(partial response)channel and SP(sum-product)decoder using the check matrix of LDPC(low density parity check)code. As the jitter-like medium n...
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki
IEICE technical report. Magnetic recording   110(68) 67-71   Jun 2010
The neuro-interpolator(NI)integrating an interpolator with a neural network equalizer in holographic data storage is proposed to reduce the influence of interpixel interference due to the aperture restriction which limits the effective recording a...
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   110(68) 21-26   Jun 2010
In this report, we evaluate the performance of the write-margin for the low-density parity-check(LDPC)coding and iterative decoding system in the bit-patterned media(BPM) R/W channel affected by the write-head field gradient, the media switching f...
Terashima T., Nakamura Y., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2010(2) "S-27"   Mar 2010
Kawae M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the IEICE General Conference   2010(2) "S-26"   Mar 2010
Yamashita J., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2010(2) "S-25"   Mar 2010
Ozaki K., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2010(2) "S-23"   Mar 2010
Natsui S., Osawa H., Okamoto Y., Nakamura Y.
Proceedings of the IEICE General Conference   2010(2)    Mar 2010
OSAWA Hisashi, KAWAE Masayuki, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
ITE Technical Report   33(57) 19-26   Dec 2009
The neural network equalizer (NNE) for the partial response maximum likelihood (PRML) system with a post-processor in perpendicular magnetic recording is studied. First, a design method of NNE is proposed for suppressing a high-level noise at the ...
OSAWA Hisashi, KAWAE Masayuki, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   109(328) 19-26   Dec 2009
The neural network equalizer(NNE) for the partial response maximum likelihood (PRML) system with a post-processor in perpendicular magnetic recording is studied. First, a design method of NNE is proposed for suppressing a high-level noise at the d...
Yamashita J., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2009(2)    Sep 2009
Kawae M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the Society Conference of IEICE   2009(2)    Sep 2009
Nakahama T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2009(2)    Sep 2009
Yamashita M., Osawa H., Okamoto Y., Nakamura Y.
Proceedings of the Society Conference of IEICE   2009(2)    Sep 2009
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
ITE Technical Report   33(22) 59-64   Jun 2009
Low-density parity check (LDPC) coding and iterative decoding system is studied in a magnetic recording system using bit-patterned media (BPM) with recording error. In order to correctly write the recording sequence on the intended islands in the ...
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   109(80) 59-64   Jun 2009
Low-density parity check (LDPC) coding and iterative decoding system is studied in a magnetic recording system using bit-patterned media (BPM) with recording error. In order to correctly write the recording sequence on the intended islands in the ...
Yamashita M., Osawa H., Okamoto Y., Nakamura Y.
Proceedings of the IEICE General Conference   2009(2)    Mar 2009
Katayama Y., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the IEICE General Conference   2009(2)    Mar 2009
Shinozaki J., Okamoto Y., Nakamura Y., Osawa H.
Proceedings of the IEICE General Conference   2009(2)    Mar 2009
Bushisue T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2009(2)    Mar 2009
NAKAMURA Yasuaki, HARUGAICHI Shintaro, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
ITE Technical Report   32(55) 19-24   Dec 2008
It is an issue that the iterative decoding system using the soft-output information based on a posteriori probability(APP) requires the huge memory. In this paper, the amount of required memory and the bit error rate performance are evaluated for ...
NAKAMURA Yasuaki, HARUGAICHI Shintaro, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   108(346) 19-24   Dec 2008
It is an issue that the iterative decoding system using the soft-output information based on a posteriori probability (APP) requires the huge memory. In this paper, the amount of required memory and the bit error rate performance are evaluated for...
OKAMOTO Yoshihiro, BUSHISUE Taku, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
ITE Technical Report   32(41) 49-54   Oct 2008
A method to make the R/W waveform sequence with required proportion of noise power and SNR is studied in this report. In addition, we study whether the R/W waveform sequence made by our proposed method can be used for evaluation of signal processi...
OSAWA Hisashi, HINO Masaya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
ITE Technical Report   32(41) 43-48   Oct 2008
The neural network equalization for a generalized partial response maximum likelihood (GPRML) system in a perpendicular magnetic recording channel with thermal decay is studied. First, a designing method of the simplified neural network equalizer ...
OSAWA Hisashi, HINO Masaya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   108(234) 43-48   Oct 2008
The neural network equalization for a generalized partial response maximum likelihood (GPRML) system in a perpendicular magnetic recording channel with thermal decay is studied. First, a designing method of the simplified neural network equalizer ...
OKAMOTO Yoshihiro, BUSHISUE Taku, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   108(234) 49-54   Oct 2008
A method to make the R/W waveform sequence with required proportion of noise power and SNR is studied in this report. In addition, we study whether the R/W waveform sequence made by our proposed method can be used for evaluation of signal processi...
Osawa H., Yamashita M., Okamoto Y., Nakamura Y.
Proceedings of the Society Conference of IEICE   2008(2)    Sep 2008
Nakahama T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2008(2)    Sep 2008
Bushisue T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2008(2)    Sep 2008
Masuda D., Nakamura Y., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2008(2)    Sep 2008
Seike Y., Okamoto Y., Nakamura Y., Osawa H., Aoi H., Muraoka H.
Proceedings of the Society Conference of IEICE   2008(2)    Sep 2008
OSAWA Hisashi, TAKAHASHI Yuzo, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
ITE Technical Report   32(28) 21-26   Jul 2008
The configuration of the suitable recording code for a partial response maximum likelihood (PRML) system in a perpendicular magnetic recording channel with thermal decay is discribed. The relationships between the run-length of recording code and ...
OSAWA Hisashi, TAKAHASHI Yuzo, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
電子情報通信学会技術研究報告. MR, 磁気記録   108(124) 21-26   Jul 2008
OSAWA Hisashi, TAKAHASHI Yuzo, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   108(124) 21-26   Jul 2008
The configuration of the suitable recording code for a partial response maximum likelihood (PRML) system in a perpendicular magnetic recording channel with thermal decay is discribed. The relationships between the run-length of recording code and ...
NAKAMURA Yasuaki, SATO Seigo, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
ITE Technical Report   32(23) 35-40   Jun 2008
It was difficult for the burst detector using the check matrix of LDPC code to detect a comparatively short burst. In this report, the improvement of detection ability for the short bit-flipping-like signal burst is studied. We obtain the burst de...
NAKAMURA Yasuaki, SATO Seigo, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
電子情報通信学会技術研究報告. MR, 磁気記録   108(81) 35-40   Jun 2008
NAKAMURA Yasuaki, SATO Seigo, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   108(81) 35-40   Jun 2008
It was difficult for the burst detector using the check matrix of LDPC code to detect a comparatively short burst. In this report, the improvement of detection ability for the short bit-flipping-like signal burst is studied. We obtain the burst de...
Okamoto Y., Bushisue T., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2008(2)    Mar 2008
Nakamura Y., Nishimura M., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2008(2)    Mar 2008
Nakamura Y., Sato S., Nishimura M., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2008(2)    Mar 2008
Osawa H., Hino M., Shinohara N., Okamoto Y., Nakamura Y., Miura K., Muraoka H.
Proceedings of the IEICE General Conference   2008(2)    Mar 2008
Okamoto Y., Kurihara Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2008(2)    Mar 2008
大沢 寿, 岡本 好弘, 仲村 泰明
工学ジャーナル   7 23-35   Mar 2008
仲村 泰明, 西村 光弘, 岡本 好弘
ITE technical report   32(2) 7-12   Jan 2008
OKAMOTO Yoshihiro, BUSHISUE Taku, KURIHARA Yasushi, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   107(381) 41-46   Dec 2007
Nonlinear transition shift (NLTS) influences the performance of PRML channel in perpendicular magnetic recording. For NLTS, it is thought that the write pre-compensation is useful to write the transition at the intended position. In this report, w...
岡本 好弘, 武士末 卓, 栗原 康志
ITE technical report   31(62) 41-46   Dec 2007
仲村 泰明, 西村 光弘, 岡本 好弘
ITE technical report   31(45) 19-24   Oct 2007
NAKAMURA Yasuaki, NISHIMURA Mitsuhiro, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki, NAKAMURA Yoshihisa
IEICE technical report. Magnetic recording   107(243) 19-24   Sep 2007
The performance of the LDPC code is evaluated in a perpendicular magnetic recording channel with burst-like signal degradation under a long sector format of 4096 Bytes/sector. In this report, two kinds of systems are studied. One is the LDPC codin...
Okamoto Y., Matoba M., Kawaue N., Oaswa H., Nakamura Y.
Proceedings of the Society Conference of IEICE   2007(2)    Aug 2007
Okamoto Y., Kishino K., Oaswa H., Nakamura Y., Aoi H., Muraoka H., Nakamura Y.
Proceedings of the Society Conference of IEICE   2007(2)    Aug 2007
Okamoto Y., Bushisue T., Nakamura Y., Osawa H., Muraoka H., Nakamura Y.
Proceedings of the Society Conference of IEICE   2007(2)    Aug 2007
Nakamura Y., Nishimura M., Okamoto Y., Oaswa H., Muraoka H., Nakamura Y.
Proceedings of the Society Conference of IEICE   2007(2)    Aug 2007
Oaswa H., Hino M., Shinohara N., Okamoto Y., Nakamura Y., Miura K., Muraoka H., Nakamura Y.
Proceedings of the Society Conference of IEICE   2007(2)    Aug 2007
Yasuaki Nakamura, Mitsuhiro Nishimura, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka, Yoshihisa Nakamura, Yoshihisa Nakamura
IEEE Transactions on Magnetics   43(6) 2277-2279   Jun 2007
An LDPC coding and iterative decoding system is studied in perpendicular magnetic recording (PMR) with a bit-patterned medium. We propose an iterative decoding scheme using attenuated extrinsic information from a sum-product decoder, and the bit e...
Nobuhiko Shinohara, Hisashi Osawa, Yoshihiro Okamoto, Yasuaki Nakamura, Atsushi Nakamoto, Kenji Miura, Hiroaki Muraoka, Yoshihisa Nakamura, Yoshihisa Nakamura
IEEE Transactions on Magnetics   43(6) 2262-2264   Jun 2007
The long-term bit error rate (BER) performance of partial response maximum likelihood (PRML) system in a perpendicular magnetic recording (PMR) channel with thermal decay is studied. A thermal decay model based on the experimental data for three C...
篠原 宜彦, 大沢 寿, 岡本 好弘
ITE technical report   31(25) 49-54   Jun 2007

Books etc

 
Advanced Technologies of Perpendicular Magnetic Recording
2007   

Conference Activities & Talks

 
増田圭太, 仲村泰明, 西川まどか, 岡本好弘, 金尾太郎, 佐藤利江
電子情報通信学会技術研究報告   31 May 2018   
西川まどか, 仲村泰明, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会技術研究報告   31 May 2018   
増田圭太, 仲村泰明, 西川まどか, 大沢寿, 岡本好弘, 金尾太郎, 佐藤利江
電子情報通信学会大会講演論文集(CD-ROM)   6 Mar 2018   
西川まどか, 仲村泰明, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会大会講演論文集(CD-ROM)   6 Mar 2018   
西川まどか, 仲村泰明, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会技術研究報告   30 Nov 2017   
西川まどか, 仲村泰明, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会技術研究報告   12 Oct 2017   
仲村泰明, 西川まどか, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会技術研究報告   12 Oct 2017   
仲村泰明, 西川まどか, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会大会講演論文集(CD-ROM)   29 Aug 2017   
T. Kondoh, Y. Nakamura, M. Nishikawa, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoka
2017 IEEE International Magnetics Conference, INTERMAG 2017   10 Aug 2017   
© 2017 IEEE. Two-dimensional magnetic recording (TDMR) which combines shingled magnetic recording (SMR) [1] with two-dimensional signal processing attracts attention in hard disk drives (HDDs).
R. Suzuto, Y. Nakamura, M. Nishikawa, H. Osawa, Y. Okamoto, Y. Kanai, H. Muraoka
2017 IEEE International Magnetics Conference, INTERMAG 2017   10 Aug 2017   
© 2017 IEEE. Hard disk drives (HDDs) have played the central role as the information storage system.
仲村泰明, 上野裕貴, 西川まどか, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会技術研究報告   1 Jun 2017   
近藤宰吉, 仲村泰明, 西川まどか, 大沢寿, 岡本好弘, 金井靖, 村岡裕明
電子情報通信学会大会講演論文集(CD-ROM)   7 Mar 2017   
鈴藤 稜太, 仲村 泰明, 大沢 寿, 岡本 好弘, 金井 靖, 村岡 裕明
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報   8 Dec 2016   
鈴藤 稜太, 仲村 泰明, 大沢 寿, 岡本 好弘, 金井 靖, 村岡 裕明
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報   9 Jun 2016   
鈴藤 稜太, 仲村 泰明, 大沢 寿, 岡本 好弘, 金井 靖, 村岡 裕明
映像情報メディア学会技術報告 = ITE technical report   Jun 2016   
Suzuto Ryota, Nakamura Yasuaki, Osawa Hisashi, Okamoto Yoshihiro, Kanai Yasushi, Muraoka Hiroaki
Proceedings of the IEICE General Conference   1 Mar 2016   
Musha Atsushi, Shimizu Osamu, Nakamura Yasuaki, Okamoto Yoshihiro
ITE Transactions on Media Technology and Applications   2016   
Tape systems experience large speed variations compared to disk systems, and therefore, it is necessary to design a stable timing recovery scheme that can operate under a low signal-to-noise ratio (SNR) condition. In such low SNR scenarios, the de...
Suzuto Ryota, Nakamura Yasuaki, Osawa Hisashi, Okamoto Yoshihiro, Kanai Yasushi, Muraoka Hiroaki
Proceedings of the Society Conference of IEICE   25 Aug 2015   
A study on rotation of reading sensitivity in SMR R/W channel
OKAMOTO Yoshihiro
IEEE The 26th Magnetic Recording Conference   17 Aug 2015   
Nakamura Yasuaki, Osawa Hisashi, Okamoto Yoshihiro, Kanai Yasushi, Muraoka Hiroaki
Proceedings of the IEICE General Conference   24 Feb 2015   
Kawamura S., Okamoto Y., Nakamura Y., Osawa H., Kanai Y., Muraoka H.
Proceedings of the IEICE General Conference   24 Feb 2015   
MUSHA Atsushi, SHIMIZU Osamu, NAKAMURA Yasuaki, OKAMOTO Yoshihiro
IEICE technical report. Magnetic recording   11 Dec 2014   
Timing recovery method for high density tape storage system is studied. Since tape system suffers from large speed variation compared to the disk system, the design of a stable PLL circuit which can operate under low signal to noise ratio (SNR) co...
SUZUTOU Ryouta, NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, KANAI Yasushi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   4 Dec 2014   
Two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) exploits two-dimensional signal processing using the waveforms reproduced by array head from intended and adjacent tracks. However, array head has the issue on the degr...
FUJIMOTO Naoki, NAKAMURA Yasuaki, OSAWA Hisashi, OKAMOTO Yoshihiro, KANAI Yasushi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   4 Dec 2014   
The two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) exploits two-dimensional signal processing using the read-back waveforms from the neighboring tracks as well as the intended track. In this report, two-dimensional ...
Nakamura Yasuaki, Suzutou Ryouta, Osawa Hisashi, Okamoto Yoshihiro, Kanai Yasushi, Muraoka Hiroaki
Proceedings of the Society Conference of IEICE   9 Sep 2014   
OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, KANAI Yasushi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   5 Jun 2014   
Read/write simulation like demonstration is performed to evaluate the performance of signal processing. A granular medium made on simulator is magnetized by a writer, and SMR (shingled magnetic recording) pattern is obtained. The performance of LD...
岡本 好弘, 仲村 泰明, 大沢 寿
映像情報メディア学会技術報告 = ITE technical report   Jun 2014   
Fujimoto N., Nakamura Y., Osawa H., Okamoto Y., Muraoka H.
Proceedings of the IEICE General Conference   4 Mar 2014   
Nobuhara H., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   4 Mar 2014   
NAKAMURA Yasuaki, YANAGITA Michita, OSAWA Hisashi, OKAMOTO Yoshihiro, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   14 Jun 2013   
The LDPC coding and iterative decoding system has high decoding gain, but decoding error increases by the iterative decoding in low SNR area due to error propagation. In this research, we propose a new SP decoding with an error propagation suppres...
Embara H., Okamoto Y., Nakamura Y., Yamashita M., Ohsawa H., むらおか H.
Proceedings of the IEICE General Conference   5 Mar 2013   
Yamashita M., Okamoto Y., Nakamura Y., Ohsawa H., S. Greaves, むらおか H.
Proceedings of the IEICE General Conference   5 Mar 2013   
TAKADA KAZUKI, OKAMOTO Yoshihiro, NOBUHARA Hirofumi, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   6 Dec 2012   
A measurement method of nonlinear transition shift (NLTS) and the write precompensation in the shingled magnetic recording (SMR) are studied. In SMR R/W channel using a discrete granular medium composed of the discrete Voronoi diagram, we measure ...
Yasuaki Nakamura, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka
GLOBECOM - IEEE Global Telecommunications Conference   1 Dec 2012   
The write-margin of the iterative decoding systems for the binary and non-binary low-density parity-check (LDPC) codes are studied in the magnetic recording system using a bit-patterned medium (BPM) R/W channel with write-errors caused by the writ...
Yasuaki Nakamura, Yoshihiro Okamoto, Hisashi Osawa, Hajime Aoi, Hiroaki Muraoka
2012 International Symposium on Information Theory and Its Applications, ISITA 2012   1 Dec 2012   
The magnetic recording system using a bit-patterned medium (BPM) has serious problems such as the need of the precise write-synchronization to correctly write the recording sequence on each intended island and the write-errors caused by the insuff...
Yamashita M., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   28 Aug 2012   
Nobuhara H., Okamoto Y., Nakamura Y., Yamashita M., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   28 Aug 2012   
Ueda J., Nakamura Y., Okamoto Y., Osawa H., Aoi H., Muraoka H.
Proceedings of the Society Conference of IEICE   28 Aug 2012   
NAKAMURA Yasuaki, UEDA Jun, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   7 Jun 2012   
The symbol-by-symbol turbo equalization for non-binary low-density parity-check (LDPC) coding system is studied in magnetic recording using the bit-patterned medium (BPM) with write-errors. In this report, we evaluated the performance of the turbo...
仲村 泰明, 上田 純, 岡本 好弘
映像情報メディア学会技術報告   Jun 2012   
Nakamura Yasuaki, Bandai Yasuhisa, Okamoto Yoshihiro, Osawa Hisashi, Aoi Hajime, Muraoka Hiroaki
Proceedings of the IEICE General Conference   6 Mar 2012   
Yamashita M., Okamoto Y., Nakamura Y., Osawa H., Miura K., Greaves S., Aoi H., Kanai Y., Muraoka H.
Proceedings of the IEICE General Conference   6 Mar 2012   
NAKAMURA Yasuaki, UEDA Jun, BANDAI Yasuhisa, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   8 Dec 2011   
Symbol-by-symbol a posteriori probability (APP) decoder for non-binary low-density parity-check (LDPC) coding and iterative decoding system in perpendicular magnetic recording channel is studied. In this report, we evaluated the performance of the...
YAMASHITA Masato, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MIURA Kenji, GREAVES Simon, AOI Hajime, KANAI Yasushi, MURAOKA Hiroaki
電子情報通信学会技術研究報告. MR, 磁気記録   8 Dec 2011   
YAMASHITA Masato, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MIURA Kenji, GREAVES Simon, AOI Hajime, KANAI Yasushi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   8 Dec 2011   
Modeling of writing process based on a discrete Voronoi model is studied for two-dimensional magnetic recording (TDMR). This is a simple but accurate model considering the influence of write head field gradient, media switching field distribution,...
山下 正人, 岡本 好弘, 仲村 泰明
映像情報メディア学会技術報告   Dec 2011   
Bandai Y., Nakamura Y., Okamoto Y., Osawa H., Aoi H., Muraoka H.
Proceedings of the Society Conference of IEICE   30 Aug 2011   
Yamashita M., Okamoto Y., Nakamura Y., Osawa H., Miura K., Greaves S., Aoi H., Kanai Y., Muraoka H.
Proceedings of the Society Conference of IEICE   30 Aug 2011   
NAKAMURA Yasuaki, BANDAI Yasuhisa, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hazime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   8 Jul 2011   
The write errors are caused by the write head field gradient, the media switching field distribution (SFD), the demagnetization field from adjacent islands and the island position deviation in the R/W channel using the bit-patterned media (BPM). I...
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MIURA Kenji, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   8 Jul 2011   
Modeling of granular medium with non-magnetic grain boundaries using a discrete Voronoi diagram is proposed for two-dimensional magnetic recording. Simplified two-dimensional neural network equalizer (2D-NNE) is also proposed to mitigate the influ...
仲村 泰明, 萬代 康久, 岡本 好弘
ITE technical report   Jul 2011   
Yamashita M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the IEICE General Conference   28 Feb 2011   
Yamashita J., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   28 Feb 2011   
Morikawa T., Nakamura Y., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   28 Feb 2011   
Okinaka K., Nakamura Y., Okamoto Y., Osawa H.
Proceedings of the IEICE General Conference   28 Feb 2011   
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, SUZUKI Yoshio, MIURA Kenji, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   2 Dec 2010   
Read/write channel modeling using a discrete Voronoi diagram is studied for two-dimensional magnetic recording. The simple closed-form representation of reader sensitivity function with fitting parameters given by linear combinations of geometry p...
山下 正人, 大沢 寿, 岡本 好弘
ITE technical report   Dec 2010   
OSAWA Hisashi, KAWAE Masayuki, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   7 Oct 2010   
The neural network equalization for LDPC coding and iterative decoding system in perpendicular magnetic recording is studied. First, a design method of neural network equalizer (NNE) is proposed for LDPC coding and iterative decoding system. In ou...
大沢 寿, 河江 政幸, 岡本 好弘
ITE technical report   Oct 2010   
NATSUI Shogo, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki
Proceedings of the ... ITE annual convention   31 Aug 2010   
A simplification method of neural network equalizer(NNE) fitting in the recording code is studied in holographic data storage. A 40 percent reduction in the number of connections in the NNE is attained without performance degradation.
OKINAKA Kazutaka, NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi
Proceedings of the ... ITE annual convention   31 Aug 2010   
The performances of the PRML systems are evaluated in a two-photon absorption recording channel model. The results show that the PR(1,2,2,2,1)ML system has the better performance compared with the PR(1,2,2,1)ML system.
TERASHIMA Taiki, NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
Proceedings of the ... ITE annual convention   31 Aug 2010   
The RS code is usually decoded using a hard-decision decoding algorithm in HDD. In this study, the soft-decision iterative decoding for the RS code is studied as the sub-optimal decoding in the perpendicular magnetic recording channel.
Kawae M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the Society Conference of IEICE   31 Aug 2010   
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki
ITE Technical Report   10 Jun 2010   
The neuro-interpolator (NI) integrating an interpolator with a neural network equalizer in holographic data storage is proposed to reduce the influence of interpixel interference due to the aperture restriction which limits the effective recording...
YAMASHITA Jyunya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
ITE Technical Report   10 Jun 2010   
The iterative decoder is composed of APP (a posteriori probability) decoder using the characteristics of PR (partial response) channel and SP (sum-product) decoder using the check matrix of LDPC (low density parity check) code. As the jitter-like ...
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
ITE Technical Report   10 Jun 2010   
In this report, we evaluate the performance of the write-margin for the low-density parity-check (LDPC) coding and iterative decoding system in the bit-patterned media (BPM) R/W channel affected by the write-head field gradient, the media switchin...
YAMASHITA Jyunya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   3 Jun 2010   
The iterative decoder is composed of APP(a posteriori probability)decoder using the characteristics of PR(partial response)channel and SP(sum-product)decoder using the check matrix of LDPC(low density parity check)code. As the jitter-like medium n...
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   3 Jun 2010   
In this report, we evaluate the performance of the write-margin for the low-density parity-check(LDPC)coding and iterative decoding system in the bit-patterned media(BPM) R/W channel affected by the write-head field gradient, the media switching f...
YAMASHITA Masato, OSAWA Hisashi, OKAMOTO Yoshihiro, NAKAMURA Yasuaki
IEICE technical report. Magnetic recording   3 Jun 2010   
The neuro-interpolator(NI)integrating an interpolator with a neural network equalizer in holographic data storage is proposed to reduce the influence of interpixel interference due to the aperture restriction which limits the effective recording a...
Terashima T., Nakamura Y., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2 Mar 2010   
Kawae M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the IEICE General Conference   2 Mar 2010   
Yamashita J., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2 Mar 2010   
Ozaki K., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   2 Mar 2010   
Natsui S., Osawa H., Okamoto Y., Nakamura Y.
Proceedings of the IEICE General Conference   2 Mar 2010   
OSAWA Hisashi, KAWAE Masayuki, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
ITE Technical Report   10 Dec 2009   
The neural network equalizer (NNE) for the partial response maximum likelihood (PRML) system with a post-processor in perpendicular magnetic recording is studied. First, a design method of NNE is proposed for suppressing a high-level noise at the ...
OSAWA Hisashi, KAWAE Masayuki, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   3 Dec 2009   
The neural network equalizer(NNE) for the partial response maximum likelihood (PRML) system with a post-processor in perpendicular magnetic recording is studied. First, a design method of NNE is proposed for suppressing a high-level noise at the d...
Kawae M., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the Society Conference of IEICE   1 Sep 2009   
Nakahama T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   1 Sep 2009   
Yamashita M., Osawa H., Okamoto Y., Nakamura Y.
Proceedings of the Society Conference of IEICE   1 Sep 2009   
Yamashita J., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   1 Sep 2009   
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
ITE Technical Report   11 Jun 2009   
Low-density parity check (LDPC) coding and iterative decoding system is studied in a magnetic recording system using bit-patterned media (BPM) with recording error. In order to correctly write the recording sequence on the intended islands in the ...
NAKAMURA Yasuaki, OKAMOTO Yoshihiro, OSAWA Hisashi, AOI Hajime, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   4 Jun 2009   
Low-density parity check (LDPC) coding and iterative decoding system is studied in a magnetic recording system using bit-patterned media (BPM) with recording error. In order to correctly write the recording sequence on the intended islands in the ...
Bushisue T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the IEICE General Conference   4 Mar 2009   
Shinozaki J., Okamoto Y., Nakamura Y., Osawa H.
Proceedings of the IEICE General Conference   4 Mar 2009   
Katayama Y., Osawa H., Okamoto Y., Nakamura Y., Muraoka H.
Proceedings of the IEICE General Conference   4 Mar 2009   
Yamashita M., Osawa H., Okamoto Y., Nakamura Y.
Proceedings of the IEICE General Conference   4 Mar 2009   
NAKAMURA Yasuaki, HARUGAICHI Shintaro, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
ITE Technical Report   11 Dec 2008   
It is an issue that the iterative decoding system using the soft-output information based on a posteriori probability(APP) requires the huge memory. In this paper, the amount of required memory and the bit error rate performance are evaluated for ...
NAKAMURA Yasuaki, HARUGAICHI Shintaro, OKAMOTO Yoshihiro, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   4 Dec 2008   
It is an issue that the iterative decoding system using the soft-output information based on a posteriori probability (APP) requires the huge memory. In this paper, the amount of required memory and the bit error rate performance are evaluated for...
OSAWA Hisashi, HINO Masaya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
ITE Technical Report   9 Oct 2008   
The neural network equalization for a generalized partial response maximum likelihood (GPRML) system in a perpendicular magnetic recording channel with thermal decay is studied. First, a designing method of the simplified neural network equalizer ...
OKAMOTO Yoshihiro, BUSHISUE Taku, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
ITE Technical Report   9 Oct 2008   
A method to make the R/W waveform sequence with required proportion of noise power and SNR is studied in this report. In addition, we study whether the R/W waveform sequence made by our proposed method can be used for evaluation of signal processi...
OKAMOTO Yoshihiro, BUSHISUE Taku, NAKAMURA Yasuaki, OSAWA Hisashi, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   2 Oct 2008   
A method to make the R/W waveform sequence with required proportion of noise power and SNR is studied in this report. In addition, we study whether the R/W waveform sequence made by our proposed method can be used for evaluation of signal processi...
OSAWA Hisashi, HINO Masaya, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   2 Oct 2008   
The neural network equalization for a generalized partial response maximum likelihood (GPRML) system in a perpendicular magnetic recording channel with thermal decay is studied. First, a designing method of the simplified neural network equalizer ...
Seike Y., Okamoto Y., Nakamura Y., Osawa H., Aoi H., Muraoka H.
Proceedings of the Society Conference of IEICE   2 Sep 2008   
Masuda D., Nakamura Y., Okamoto Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2 Sep 2008   
Nakahama T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2 Sep 2008   
Osawa H., Yamashita M., Okamoto Y., Nakamura Y.
Proceedings of the Society Conference of IEICE   2 Sep 2008   
Bushisue T., Okamoto Y., Nakamura Y., Osawa H., Muraoka H.
Proceedings of the Society Conference of IEICE   2 Sep 2008   
OSAWA Hisashi, TAKAHASHI Yuzo, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
ITE Technical Report   10 Jul 2008   
The configuration of the suitable recording code for a partial response maximum likelihood (PRML) system in a perpendicular magnetic recording channel with thermal decay is discribed. The relationships between the run-length of recording code and ...
OSAWA Hisashi, TAKAHASHI Yuzo, OKAMOTO Yoshihiro, NAKAMURA Yasuaki, MURAOKA Hiroaki
IEICE technical report. Magnetic recording   3 Jul 2008   
The configuration of the suitable recording code for a partial response maximum likelihood (PRML) system in a perpendicular magnetic recording channel with thermal decay is discribed. The relationships between the run-length of recording code and ...

Works

 
Research on next generation peta byte information storage
2008

Research Grants & Projects

 
Study on Signal Processing for high Density Recording of Information Strange