| Project/Area Number |
11680481
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
プラズマ理工学
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| Research Institution | Shizuoka University |
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Principal Investigator |
INUZUKA Hiroshi Shizuoka University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (80176411)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | spectral analysis for non-stationary signal / micro wave / reflectometer / density profile measurements / plasma / Wavelet analysis / Wigner distribution / cross component / クロス項 / FFT |
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| Research Abstract |
The spatial resolutions of the microwave or millimeter wave reflectometers are restricted by the frequency characteristics of high frequency filters using in the frequency discrimination of the signal processing in the beat signals. Recently, time-resolved spectral analysis techniques have been used in the discrimination instead of these filters. We have compared using simulations these spectral analysis techniques, Fast Fourier Transform (FFT), Maximum Entropy Method (MEM), Wigner distribution, and wavelet analysis for refletometric measurements in the light of the accuracy of the re-constructed density distribution.The spectral analyses for the non-stationary signals have advantage for the density distribution with steepness.
The Wigner distribution is a valuable tool for time-frequency signal analysis of non-stationary signals. However, artificial spectral peaks called cross-components are superposed to real peaks in the Wigner distribution of multi-components signals. We introduces techniques to suppress the cross-components of the signals with no broad spectral. This method is not universal algorithm, but the time and frequency resolution is not degraded by this operation for the elimination of cross-components.
Their techniques was applied to the data analysis using the Wigner distribution of the simulation in the reflectometer, and it was shown that the accuracy was drastically improved. The effectiveness was confirmed on showing that the techniques applicable to not only simulations but also experiments of FM reflectometer of the microwave band. The above result was reported in some academic journals.
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