| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 86 ===
In general, when we process signals, we often make use of spectrum to analyze the characteristic of signal. Because some limitations of FFT usually cause spectrum some errors, it is necessary to recommend a method to improve the spectrum. The purpose of this thesis is to afford a method that can compute the amplitude and frequency accurately, and improve the accuracy of spectrum.
This method afforded in this thesis includes two steps. The first step makes use of the original spectrum to obtain more accurate frequency and amplitude. And the second step performs the slight scale-adjustment. In the first step. we ofer two methods-the gravity center methd and the reFFT method. The gravity center emthod makes us be able to obtain more accurate frequency, and the reFFT method makes us be able to obtain more accurate amplitude. In the second step, we use the least total leakage energy as base to find out the magnitude of the optimized scale-adjustment .Meanwhile, we make use of this magnitude to adjust the frequency scale in order to show the frequency and amplitude clearly and accurately in the spectrum.
Finally, we use actual signals to validate and evaluate our methods.
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