ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
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25.81
Displaying 1-10 of 10 articles from this issue
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  • [title in Japanese]
    Article type: Cover
    Pages Cover1-
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_Cover1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • [title in Japanese]
    Article type: Index
    Pages Toc1-
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_Toc1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Preparation and Magnetic Properties of Sr-M Ferrite Thin Films with Large Perpendicular Magnetic Anisotropy
    Shigeki NAKAGAWA, Keisuke MIZUNO, Nobuhiro MATSUSHITA
    Article type: Article
    Session ID: MMS2001-108
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_1
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Magneto-plumbite type of Ba ferrite(BaM)and Sr ferrite(SrM)thin films deposited on Pt underlayer with(111)-plane orientation exhibited good crystallinity and c-axis orientation even though the thickness of BaM films was only 8nm. BaM/Pt multilayered configuration was effective to overcome the degradation of perpendicular coercivity H_<c&bottom;> and squareness S_&bottom; at thinner BaM layer region. Sr ferrite(SrM)ferrite thin films deposited using Ar and Kr mixture gas as sputtering gas revealed better crystallinity and c-axis orientation even though the thickness of SrM layer below 20 nm. SrM ferrite thin films with large perpendicular magnetic anisotropy and high H_<c&bottom;> of about 3kOe was obtained at Ts of 450℃
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  • Data scramble method for phase change optical disks
    Yukari KATAYAMA, Shigeki TAIRA, Takushi NISHIYA, Harukazu MIYAMOTO, Ta ...
    Article type: Article
    Session ID: MMS2001-109
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_7
    CONFERENCE PROCEEDINGS FREE ACCESS
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    New scrambling method is described. DVD-RAM is a phase-change optical disk which records data by controlling two phases(a crystalline state and an amorphous state). In case the same data is written on the same place repeatedly, the phase-change optical disks deteriorate. To prevent the deterioration of the media, random seed scrambling method is proposed. In the random seed scrambling the data is scrambled by a different seed whenever the data is written on the media, and therefore, a different data is over-written on the media all the time. The proposed random seed scrambling has a characteristic that the seed is not necessary to be de-scrambled. By using random seed scrambling method, the overwrite characteristic of phase-change optical disks is improved drastically and a number of overwrite times increases. Key words DVD, Phase change optical disks, scrambling, over write
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  • Consideration of non-linearity at readout process on optical disk
    Takeshi Maeda, Takeshi Shimano
    Article type: Article
    Session ID: MMS2001-110
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_13
    CONFERENCE PROCEEDINGS FREE ACCESS
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    In the read-write channel of an optical disk system, a significant component of non-linearity arises in the writing process. This has been eliminated by linearizing write control. However, as linear density increases, the component of non-linearity in the readout process becomes not negligible. Therefore, we attempted to analyze the causes of the non-linearity component. We uses scalar diffraction theory, to compare the superposition of a response from a unit mark to a real respomse. The results show that this component was generated by the cross-product of two amplitudes of a diffraction light. We also estimated the size of this componenet on a mark-edge recording, in which the mark was increased by an additional unit mark. To do this, we calculated the response from an additional unit mark, which was the difference between the response from the previously added mark and that from the added mark, and compared this response with marks of different lengths.
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  • Real Time State-Splitting and Stethering Encoder
    Hiroshi KAMABE
    Article type: Article
    Session ID: MMS2001-111
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_19
    CONFERENCE PROCEEDINGS FREE ACCESS
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    A real-time state splitting method was introduced to construct simple encoders even if the code length is very long. A stethering encoder was introduced to constrcut encoders and decoders with low complexity. We compare these methods and show that by combining principles of these methods we can construct a pair of encoder and decoder with low complexity.
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  • Simulation for Multi-level Magnetic Recording using Continuous Phase Modulation
    Hideaki MAEDA, Seiichi MITA, Lijun LI
    Article type: Article
    Session ID: MMS2001-112
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_25
    CONFERENCE PROCEEDINGS FREE ACCESS
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    We have used the PRML signaling for HDD. In the PRML, information data series are presented in the manner of magnetic transition amplitudes. In CPM(Continuous Phase Modulation), the differences of phase and frequency of modulated signal at each time present the information data series. On the use of these characteristics, a multi-level recording can be realized. We have confirmed that this multi-level recording can improve S/N by 4dB through several simulations.
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  • Signal Processing Channel for Perpendicular Magnetic Recording Systems
    Hideki SAWAGUCHI, Yasutaka NISHIDA, Hisashi TAKANO, Hiroyuki TSUCHINAG ...
    Article type: Article
    Session ID: MMS2001-113
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_31
    CONFERENCE PROCEEDINGS FREE ACCESS
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    We designed an optimal partial-response maximum-likelihood(PRML)channel for a high-density perpendicular magnetic recording system using a single-pole-type(SPT)recording head and a double-layered medium. The first key feature is a generalized PR(GPR)channel to achieve nearly optimal noise-whitening filtering for the desired recording channel. The second key feature is a class-III-based GPR(GPR3)channel with suppressed low-frequency components to provide a better match with a DC-distorted channel. We confirmed that for the media-noise-dominant channel, the new GPR3 channel improved the SNR by more than 1.8 dB compared to other types of PRML channels.
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  • Introduction to Low Density Parity Check Codes and the Sum-Product Algorithm
    Tadashi WADAYAMA
    Article type: Article
    Session ID: MMS2001-114
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_39
    CONFERENCE PROCEEDINGS FREE ACCESS
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    This article gives tutorial on basics of low density parity check(LDPC)codes and the sum-product algorithm. Detailed explanation on probability-domain sum-product algorithm and log-domain sum product algorithm are also included.
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  • [title in Japanese]
    Article type: Appendix
    Pages App1-
    Published: December 13, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.81.0_App1
    CONFERENCE PROCEEDINGS FREE ACCESS
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