ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
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22.69
Displaying 1-11 of 11 articles from this issue
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  • [title in Japanese]
    Article type: Cover
    Pages Cover1-
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_Cover1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • [title in Japanese]
    Article type: Index
    Pages Toc1-
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_Toc1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Two-Dimensional Coding for The Perpendicular with MR head and Double Layered Medium
    Saburo TAZAKI, Hiroaki OOBAYASHI, Yoshimasa ODA, Sinji TSUZUKI, Yoshio ...
    Article type: Article
    Pages 1-6
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_1
    CONFERENCE PROCEEDINGS FREE ACCESS
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    This paper proposes a new model of approximated function under the fidelity to the read-back waveform on perpendicular magnetic recording using MR head and double layered medium and compares the performance with the conventional model with integlation format of Lorentzian function at higher density storage. We apply two recording codes for the performance comparison of both models : classical 2/3 (1,7) code and 5/4 (2,k_v=4 ; L=3) code where L means the number of multi-track. As to 2/3 (1,7) code, our proposed model shows a little superiority to conventional model with required SN ratio at BER=10^<-5>. However, as for 5/4 (2,4 ; 3) code, the difference on the performance between both models isn't clear even though their required SN ratio at BER=10^<-5> is better about 5dB than those of 2/3 (1,7) code.
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  • Periodical Time-Varying Punctured Convolutional Code and MTR Convolutional Code for Partial Response Recording Channel
    Hideaki MAEDA, Norimichi HIRANO, Ryuji KOHNO
    Article type: Article
    Pages 7-12
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_7
    CONFERENCE PROCEEDINGS FREE ACCESS
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    This paper proposes a Time-Varying Punctured Convolutional Code (PCC) with high data rate for high density magnetic recording. Consider matching the PR Precoder and PCC encoder, Signal-to-Noize Ratio (SNR) can be improved 3.0 dB over the usual method at normalized liner density K=3.0 and BER=10^<-4>. Moreover, a method of combining MTR code with the proposed system ising a Time-Varying PCC is proposed. The method can obtain 1.2 dB gain over a usual method at K=3.0,BER=10^<-4>.
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  • Construction and Performance Evaluation of a Rate 9/10 Trellis Code for E^2PR4ML System
    Hidetoshi SAITO, Yoshihiro OKAMOTO, Hisashi OSAWA
    Article type: Article
    Pages 13-20
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_13
    CONFERENCE PROCEEDINGS FREE ACCESS
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    A new rate 9/10 trellis code matched to E^2PR4ML system for high density digital magnetic recording is proposed. The bit error rate performance of the TCPR system using a proposed code is obtained by computer simulation and it is compared with that of conventional 16/17 (0,6/6), 8/9 MTR coded E^2PR4ML systems. The results show that the proposed system exceeds performance of the conventional systems in high density recording. A bit error rate of 10^<-4> can be achieved with SNR of approximately 2.5,0.8dB less than the conventional 16/17 (0,6/6), 8/9 MTR coded E^2PR4ML systems at a normalized liner density of 3.
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  • A (d, k)-Constraint Coding Technique based on Prefix Codes (II)
    Tadashi WADAYAMA, Yoshimichi Komori, Yoshiharu Yuba
    Article type: Article
    Pages 21-28
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_21
    CONFERENCE PROCEEDINGS FREE ACCESS
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    When the channel can be assumed to be noiseless (or nearly noiseless), we can use a (d, k)-constraint code of long block length (e.g., larger than 100 bits). One of the promising encoding techniques of a (d, k)-constraint code of long block length is the enumerative encoding technique. Though the enumerative coding technique can yield near the optimal coding rate for a given block length, it requires integer arithmetics or floating point number arithmetics with the bit size comparable to the code length. These arithmetics are somewhat time consuming when very high speed encoding is required. We here propose an encoding scheme for a (d, k)-constraint code of long block length. The proposed scheme use tow simple prefix codes. The encoding and decoding is based on the table look up ; thus it is suitable for high speed processing. For example, a (1,3)-constraint code with the coding rate 200/378=0.529 can be constructed. For encoding/decoding the code, we only need the table of size 16×15 bits. The coding rate of this code is 5.8% greater than the coding rate of the well-known rate half (1,3)-constraint code.
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  • Simplification of Neural Network Equalizer Using Genetic Algorithm
    Hisashi Osawa, Tatsuro Kawamoto, Yoshihiro Okamoto, Hidetoshi Saito
    Article type: Article
    Pages 29-36
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_29
    CONFERENCE PROCEEDINGS FREE ACCESS
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    A searching method using genetic algorithm is studied for simplification of neural network equalizer. First, a model of read/write channel with partial erasure and a searching method using genetic algorithm are described. Then, the relationship between the required SNR to achieve a bit error rate of 10^<-4> and the reduction parameter for the 16/17 (0,6/6) coded EPR4ML system equalized by a simplified neural network is obtained by computer simulation and is compared with that of the conventional neural network equalizer. The results show that the performance of simplified neural network equalizer is equal to that of conventional neural network equalizer.
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  • An Improvement on bit error rate of M2DFE
    Masuo Umemoto
    Article type: Article
    Pages 37-44
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_37
    CONFERENCE PROCEEDINGS FREE ACCESS
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    MDFE (Multi-level Decision Feedback Equalization) with (1,7) coding has been proposed for high-density hard disk drives. An improvement on the error rate of MDFE is studied. An M2DFE^<+++> uses (1) a decision rule checking the (1,7) code constrains, and (2) one-bit error correction by parity of the number of positive states in a block of recording signals. Simulation results shows the effect of these signal processing techniques.
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  • Recent Trends of Signal Processing Technology for Hard Disk Drive
    Seiichi MITA
    Article type: Article
    Pages 45-53
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_45
    CONFERENCE PROCEEDINGS FREE ACCESS
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    The signal processing technique trends for hard disk drives are described on the basis of the signal energy preservation law and Shannon theorem. Recent developments of a signal processing LSI are also introduced. The characteristics of the high order partial response signalings such as EPRML and EEPRML with a sophisticated coding and a trellis structure are analyzed on a bit error rate and a error pattern. Moreover, the realization of 1 chip LSI and the performance improvements of error correcting codes such as turbo code and Read-Solomon code are discussed in terms of the progress of the semiconductor process.
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  • Contribution of Information Theory on Recording Code for Higher Density Storage
    Saburo Tazaki
    Article type: Article
    Pages 55-64
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_55
    CONFERENCE PROCEEDINGS FREE ACCESS
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    This paper makes clear how information theory contributes to the progression of recording codes for satisfying high density storage in the periods of infancy (before 1979), growth (1980's), and expansion (after 1990), respectively. Especially, the works with FSTD model for code construction by Franaszek, algorithm for sliding block codes by Adler, Coppersmith and Hassner, and two dimensional codes by Marcellin and Weber must be highly evaluated as the epockmaking ones in each turning point, and will be briefly introduced their essence. Finally, we scope the strategy on the contribution of coding techniques for super high density storage in the future age.
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  • [title in Japanese]
    Article type: Appendix
    Pages App1-
    Published: December 10, 1998
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.22.69.0_App1
    CONFERENCE PROCEEDINGS FREE ACCESS
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