Explanation of binning in frequency analysis post-FFT

1. What is frequency binning?
2. What is bin in Fourier transform?
3. What is number of bins in FFT?
4. Why does FFT have negative frequencies?

What is frequency binning?

frequency bins are intervals between samples in frequency domain. For example, if your sample rate is 100 Hz and your FFT size is 100, then you have 100 points between [0 100) Hz. Therefore, you divide the entire 100 Hz range into 100 intervals, like 0-1 Hz, 1-2 Hz, and so on.

What is bin in Fourier transform?

FFT Size and "Bins"

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.

What is number of bins in FFT?

The bandwidth of the FFT is divided into bins, the number of which is 1/2 the FFT length.

Why does FFT have negative frequencies?

The reason is that the Fourier transform is symmetric about the y-axis, because the Fourier transform is mathematically defined on the interval (-Inf,Inf). The actual Fourier transform therefore has negative frequencies.