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URN etd-0914109-180545 Statistics This thesis had been viewed 3062 times. Download 2238 times. Author Ming-Sheng Chen Author's Email Address No Public. Department Communication Engineering Year 2008 Semester 2 Degree Master Type of Document Master's Thesis Language zh-TW.Big5 Chinese Page Count 52 Title Using an Adjustable Window Algorithm to Improve the Measurements of Frequency domain Keyword FFT Leakage Window Window Leakage FFT Abstract The Fourier spectrum of a periodic signal may be obtained by fast Fourier transform algorithms﹐but﹐as is well know﹐special care must be taken to avoid severe distortions introduced by the sampling process﹒The main problem is the leakage generated by the truncation required to obtain a finite length sampled data﹒
The usual procedure to reduce leakage is to multiply the sampled signal by a weighting window﹒Several kinds of windows have been proposed in the literature﹐and today they are also included in many commercial instruments﹒
A simple alternative procedure is proposed in this thesis﹒The algorithm is equivalent to the use of an adjustable sampling frequency and correspondingly an adjustable window size﹒
Results obtained by this method on both harmonic and polyharmonic signals are empirically analyzed and compared with those given by other windows﹒
Advisor Committee Chau-Yun Hsu - advisor
Chien-Hua Chen - co-chair
Tsung-Ming Lo - co-chair
Files Date of Defense 2009-07-31 Date of Submission 2009-09-15