BISOPE series 10- There is an FFT to draw a spectrum (frequency graph).

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Although the first vibration was measured in China, most of the vibration theory and application of vibration started in Western Europe, and the current vibration-related industry is the most common in the United States. Therefore, the translation of common words is also different. In the field of noise and vibration, for example, it is known that octave and frequency analysis are different words, and FFT is the most used vibration word, but it is understood as frequency analysis. It's common knowledge, but it's hard to go back. Knowing the frequency means knowing the number of repetitions per second, which is the reciprocal of the period. Knowing the frequency graph means knowing the spectrum graph. However, FFT does not mean frequency transformation.

 

Fast Fourier Transform (FFT)

FFT is a redevelopment transformation equation that is a simplified transformation equation developed by a scientist named Fourier. The conversion formula expresses that ‘any complex periodic waveform can be expressed as the sum of harmonics (sinusoids), but it is worth noting that this does not mean a spectrum. In other words, a spectrum is simply a spectrum that represents the separated harmonic waves on a graph representing the number of repetitions per second. Of course, since it is very convenient to check the frequency at which the spectrum is separated, it is used for equipment diagnosis and frequency analysis, but it should be possible to distinguish literally that the spectrum is not an FFT. So, I think it is better to call the FFT as ‘waveform separator’ and ‘FFT instrument as a waveform separator’.

The Fast Fourier Transform is an algorithm that increases the efficiency of the calculation speed by using the periodicity of the trigonometric function in the calculation of the discrete Fourier transform, which simply discretizes the Fourier transform and performs the calculation. In other words, the amount of calculation is reduced by omitting the same value without performing all infinite calculations. This method was proposed by Cooley and Tukey in 1962 and made possible the emergence of the present analyzer.

Therefore, FFT analyzer is a generic term for equipment that receives a time signal, performs fast Fourier transform, and analyzes the frequency to understand the characteristics of the signal. lose Therefore, please do not mix spectrum graphs and FFTs.

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