| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency analysis technology capable of identifying a mode frequency highly accurately even in the case of short-time waveform data, while suppressing increase of the operation load. SOLUTION: When a sampled waveform data row is multiplied by a window function and a spectrum data row is generated by discrete Fourier series expansion such as FFT (fast Fourier transform) and the frequency of spectrum data with becomes the maximum value is identified as the mode frequency of a vibration phenomenon, a complex window function determined by multiplying a real window function by a complex phase term is used as the window function, and a cutout waveform data row having a shifted phase is generated by changing the value of the complex phase term, and the spectrum data row having a frequency origin shifted by the discrete Fourier series expansion such as FFT is additionally generated. |
