Is the whole data needed for the fast fourier transform with an ongoing signal?

1. How many samples do I need for FFT?
2. What does Fast Fourier Transform do to a signal?
3. How many periods do I need for FFT?
4. What are the limitations of FFT?

How many samples do I need for FFT?

The number of samples (N) in the FFT must be an integer power of 2. Therefore, N = 2^p, where p is a positive integer. This rule minimizes the number of multiplications—and therefore the computation time—needed to compute the coefficients of the Fourier series.

What does Fast Fourier Transform do to a signal?

The "Fast Fourier Transform" (FFT) is an important measurement method in the science of audio and acoustics measurement. It converts a signal into individual spectral components and thereby provides frequency information about the signal.

How many periods do I need for FFT?

Number of periods of signal required when doing an FFT: 1

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What are the limitations of FFT?

A disadvantage associated with the FFT is the restricted range of waveform data that can be transformed and the need to apply a window weighting function (to be defined) to the waveform to compensate for spectral leakage (also to be defined). An alternative to the FFT is the discrete Fourier transform (DFT).