Fft size matlab

1. How do I know my FFT size?
2. What is the output of FFT in MATLAB?
3. How many samples do I need for FFT?

How do I know my FFT size?

The FFT size defines the number of bins used for dividing the window into equal strips, or bins. Hence, a bin is a spectrum sample , and defines the frequency resolution of the window. By default : N (Bins) = FFT Size/2.

What is the output of FFT in MATLAB?

The Discrete Fourier Transform, which an FFT algorithm computes quickly, assumes the input data of length N is one period of a periodic signal. The period is 2*pi rad . The frequency of the output points is given by 2*n*pi/N rad/sec , where n is the index from 0 to N-1 .

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.