Basic FAQ for FFT Analyzer

The Fourier spectrum refers to the result of applying a Fourier transform to a time signal, expressed as a function of frequency, and is usually a complex function. However, in an FFT analyzer, the complex Fourier series is referred to as the Fourier spectrum, considering a finite time window as the fundamental period for the Fourier series expansion. Therefore, if the physical unit of the time signal is EU (V), the unit of the absolute value of the Fourier spectrum is also displayed as EU (V).

input signalWhen this is expressed in complex number form, it becomes equation (1).

Here, Re refers to the real part of a complex number.This is a vector rotating counterclockwise on the unit circle with angular velocity (angular frequency) ω (ω = 2π f,frequency f (The component) Therefore, frequency f The Fourier spectrum at is given by equation (1) t When set to = 0 Complex amplitude value () will be. Here, A and φ are the magnitudes (mag) and phases (phase) of the respective Fourier spectra.