I am reading tutorials about windowing and have read following sentence:
For an integer number of cycles, all smoothing windows yield the same peak amplitude reading and have excellent amplitude accuracy. Side lobes do not appear because the spectrum of the smoothing window approaches zero at Δf intervals on either side of the main lobe.
This term integer number of cycle, I have meet several times and please explain me what does it means? Does it means that periodic functions are integer number of cycles, because they repeat at each period, which is equal main period multiplied by some integer? What about non-periodic signals? Thanks in advance.