| Project/Area Number |
62550245
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子通信系統工学
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| Research Institution | Kagoshima University (1988)
Okayama University (1987) |
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Principal Investigator |
TANADA Yoshihiro Associate Professor, Fac. of Eng. Kagoshima University, 工学部, 助教授 (70033248)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1988: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1987: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Cyclically orthogonal real-valued pseudonoise sequences / Spread-spectrum multiple-access / Time-and code-division Multiplexing / Digital correlation / ASIC / Immunity / Security / パルス圧縮レーダ / 実数多値直交擬似雑音系列 / レーダ / スクランブル伝送 / 有限体上の多値直交擬似雑音系列 / 時分割 / 符号分割多重 |
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| Research Abstract |
This reseach has been carried out during two years from 1987 to 1989, for the purpose of establishing a foundation of spread-spectrum multiple-access system using cyclically orthogonal realvalued pseudonoise sequences whose immunity and security are higher than those of the system using M-sequences of Gold sequences. Direct-sequence spread-spectrum system has been investigated on the fundamental theory and the simple experiment to be understandable for the engineers in this field. It is shown that a multiple access system without interchannel interference is formed theoretically and is approximately realized by using digitally processed code generators and correlators. Future development of application-specific ICs (asic) will bring practical-rate spread-spectrum multiple-access system using real-valued sequence. The followings are the achievements of this project.
1. Development of cyclically orthogonal real-valued sequences for multiple access A set of sequences with the length of prime-number or power of two which are orthogonal each other at zero shift and also keep small absolute value of crosscorrelation, are deduced from general expression of cyclically orthogonal real-valued sequences with zero-sidelobe autocorrelation.
2. Research on spread-spectrum multiple-access system Proposed system of time-and code-division multiplexing using sequences with low duty ratio and with orthogonality at zero shift has non interchannel interference where delay time differences distribute in a certain range, has power efficiency of about 100 % when synchronized.
3. Research on digital signal procssing with cyclically orthogonal real-valued sequences Experiment of an ultra-sound pulse-compression radar system proves that process gain suppresses round error of digital correlator. Simulation of digital correlation through FFT also proves round error suppresion. The other sequences suitable for number-theoretic transform are investigated.
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