What is tapering in signal processing?
A Taper (or apodization function or window function) is applied to a time signal to improve its properties in the frequency domain. Taper is a tool reached from the Waveform menu, that applies a tapering function to the signals in the active signal viewer.
How many points for FFT?
Therefore, with an FFT you can only evaluate a fixed length waveform containing 512 points, or 1024 points, or 2048 points, etc.