Why we use Windows for vibration analysis and how to determine frequency resolution required for proper fault diagnosis
By Suri Ganeriwala, PhD
When you use the FFT to find the frequency content of a signal, it is inherently assumed that the data in each block is a single period of a periodically repeating waveform. The waveform corresponding to this period (each block) is then repeated in time to produce the periodic waveform. If this condition is not achieved, for example if you sample at a non-integer number of cycles such as 7.5, an issue called "spectral leakage" occurs resulting in an incorrect spectral display. Specifically, some of the energy at a given line or bin will transfer.. (more)
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