Scaled Time Domain Window VI
- Updated2025-07-30
- 2 minute(s) read
Applies a scaled window to the input sequence X. Wire data to the X input to determine the polymorphic instance to use or manually select the instance.
The Scaled Time Domain Window VI scales the result so that when the power or amplitude spectrum of the windowed waveform is computed, all windows provide the same level within the accuracy constraints of the window. The Scaled Time Domain Window VI also returns important window properties for the selected window. These properties are useful when you use VIs that perform computations on the power spectrum, such as the Power & Frequency Estimate VI and the Spectrum Unit Conversion VI.
If y represents the output sequence Windowed X, the Scaled Time Domain Window VI obtains the elements of y from:
for i = 0, 1, 2, …
where wi and cg are the coefficients and coherent gain of the window without scaling, respectively.
This VI also returns the coherent gain (CG) and equivalent noise bandwidth (ENBW) of the selected window. For cosine windows, these two properties are constants, as listed in the following table.
| Window Type | CG | ENBW |
|---|---|---|
| Rectangle | 1.0 | 1.0 |
| Hanning | 0.5 | 1.5 |
| Hamming | 0.54 | 1.362826 |
| Blackman-Harris | 0.42323 | 1.708538 |
| Exact Blackman | 0.42659071367 | 1.693699 |
| Blackman | 0.42 | 1.726757 |
| Flat Top | 0.215578948 | 3.770246506303 |
| 4 Term B-Harris | 0.35875 | 2.004353 |
| 7 Term B-Harris | 0.27105140069342415 | 2.631905 |
| Low Sidelobe | 0.323215218 | 2.215350782519 |
| Blackman Nuttall | 0.3635819 | 1.9761117 |
If X is an empty input array and the selected window is a cosine window, this VI returns the window properties. If X is an empty input array and the selected window is not a cosine window, this VI sets the window properties to NaN and returns an error. For Triangle, Kaiser, Dolph-Chebyshev, and Gaussian windows, the window properties depend on the window length and the window parameters.