A New Approach to the Improvement of FFT Spectrum Qualitity

作者:Chen Kuifu; Jiao Qunying; Gao Xiaorong
来源:Journal of Vibration, Measurement & Diagnosis, 1998, 18(3): 226-232.

摘要

Noting the continuity of discrete Fourier transform (DFT) of a finite time series, an interpolation formula for the DFT spectrum based on corresponding fast fourier transform (FFT) is derived. According to the formula, a parabolic iteration method and a computer program for searching the frequency, amplitude. and phase of a spectral peak in a frequency interval of interest are presented. The iteration can converge to the required frequency with fairly good precision in only several steps. An investigation concerning the frequency resolution and the influence of window functions on the DFT spectrum are also made, and it is pointed out that the Hanning window is suitable for a whole view spectral analysis, while the rectangular window for the local spectral analysis.

  • 出版日期1998

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