Using an Adjustable Window Algorithm to Improve the Measurements of Frequency domain

• Main Authors: Ming-Sheng Chen, 陳明笙
• Other Authors: Chau-Yun Hsu
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/26623884531137145956

碩士 === 大同大學 === 通訊工程研究所 === 97 === 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﹒