# Why do we scale bins in FFT in this code?

Hi I am learning FFT I am confused about this bit of code: what is the reason for scaling the sampling frequency and what is bin scale and why and when do we use it? thank you

Fs = 20000; % sampling frequency
Binscale = 100;
%FFT for determining fundamental frequency with 0.01Hz accuracy
k = Fs*Binscale;


• If answers are sufficient, do not hesitate to upvote and validate, please Nov 16 '20 at 6:11

This is not easy to tell without knowing the purpose. However, here is a guess. A frequency bin (in an FFT) is a subdivision of a continuous frequency axis into equally sized intervals, often called frequency resolution. The width of such an interval is determined by a maximum frequency divided by the length of the FFT. Here, a target frequency bin is set: $$0.01$$ Hertz.
Thus, I suspect that $$k$$ could be used to set a forthcoming FFT length.