Windowing (also known as weighting) functions are used to combat spectral leakage from digital signal processing (discontinuities).
The Fast Fourier Transformation (FFT) needs one period of a periodic signal. In the FFT, the discontinuities create high-frequency components, which were not present in the original signal. Therefore, a problem arises when applying FFT to measure the frequency components of a radar signal.
The windowing technique is used to overcome the aforementioned problem. It reduces the discontinuities at the boundaries. It enables the amplitude to vary smoothly and gradually reduce toward zero at the edges, resulting in a continuous waveform.
Freescopes includes the following Windowing Functions:
- Hann (also known as Hanning)