Scaled Time Domain Window VI

LabVIEW 2018 Help


Edition Date: March 2018
Part Number: 371361R-01
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Owning Palette: Windows VIs

Requires: Full Development System

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.

Details  

Use the pull-down menu to select an instance of this VI.

Scaled Time Domain Window (DBL)

X is a real vector.
window is the window to apply to X.

0Rectangle (default)
1Hanning
2Hamming
3Blackman-Harris
4Exact Blackman
5Blackman
6Flat Top
74 Term B-Harris
87 Term B-Harris
9Low Sidelobe
11Blackman Nuttall
30Triangle
31Bartlett-Hanning
32Bohman
33Parzen
34Welch
60Kaiser
61Dolph-Chebyshev
62Gaussian
window parameter specifies the beta parameter for a Kaiser window, the standard deviation for a Gaussian window, and the ratio, s, of the main lobe to the side lobe for a Dolph-Chebyshev window. If window is any other window, this VI ignores this input.

The default value of window parameter is NaN, which sets beta to 0 for a Kaiser window, the standard deviation to 0.2 for a Gaussian window, and s to 60 for a Dolph-Chebyshev window.
Windowed X is the input signal with the window applied.
window properties returns the coherent gain and equivalent noise bandwidth of the window.
eq noise BW returns the equivalent noise bandwidth of the window. You can use eq noise BW to divide a sum of individual power spectra or to compute the power in a given frequency span.
coherent gain returns the inverse of the scaling factor this VI applies to the window.
error returns any error or warning from the VI. You can wire error to the Error Cluster From Error Code VI to convert the error code or warning into an error cluster.

Scaled Time Domain Window (CDB)

X is the complex valued input sequence.
window is the window to apply to X.

0Rectangle (default)
1Hanning
2Hamming
3Blackman-Harris
4Exact Blackman
5Blackman
6Flat Top
74 Term B-Harris
87 Term B-Harris
9Low Sidelobe
11Blackman Nuttall
30Triangle
31Bartlett-Hanning
32Bohman
33Parzen
34Welch
60Kaiser
61Dolph-Chebyshev
62Gaussian
window parameter specifies the beta parameter for a Kaiser window, the standard deviation for a Gaussian window, and the ratio, s, of the main lobe to the side lobe for a Dolph-Chebyshev window. If window is any other window, this VI ignores this input.

The default value of window parameter is NaN, which sets beta to 0 for a Kaiser window, the standard deviation to 0.2 for a Gaussian window, and s to 60 for a Dolph-Chebyshev window.
Windowed X is the input signal with the window applied.
window properties returns the coherent gain and equivalent noise bandwidth of the window.
eq noise BW returns the equivalent noise bandwidth of the window. You can use eq noise BW to divide a sum of individual power spectra or to compute the power in a given frequency span.
coherent gain returns the inverse of the scaling factor this VI applies to the window.
error returns any error or warning from the VI. You can wire error to the Error Cluster From Error Code VI to convert the error code or warning into an error cluster.

Scaled Time Domain Window Details

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 Window Properties
CG ENBW
Rectangle1.0 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.

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