
A typical application of the Window I/O is to remove spectral leakage in a frequency spectrum using a Fourier Transform. The FFT I/O does have a window function built-in already, therefore using the Window I/O is not required there.
A second application is to shape signal bursts, e.g. to use in the Arbitrary Waveform Generator.
Properties
To control the behavior of the Window I/O, several properties are available. These can be accessed via a popup menu which is shown when the I/O is right clicked. The properties can also be accessed through its settings window which is shown when the I/O is double clicked.
Window function
The setting Window function defines which algorithm is used to adapt the signal. Several windows functions can be selected from:
- Rectangle
- Hanning
- Hamming
- Bartlett
- Parzen
- Welch
- Blackman
- Blackman-Harris
- Flat top
- Nuttall
- Blackman-Nuttall
The window Rectangle is basically no window, it does not change the signal.
Normalization
A Window function changes the amount of energy in the signal. When performing an FFT on the windowed signal, the magnitudes of the spectral bins will be lower than of a non-windowed signal. To compensate for that, a Normalization can be enabled, which will give the spectral bins the correct magnitudes.