WelchWindow[x]
represents a Welch window function of x.
WelchWindow[x,α]
uses the parameter α.
WelchWindow
WelchWindow[x]
represents a Welch window function of x.
WelchWindow[x,α]
uses the parameter α.
Details
- WelchWindow is a window function typically used for antialiasing and resampling.
- Window functions are used in applications where data is processed in short segments and have a smoothing effect by gradually tapering data values to zero at the ends of each segment.
- WelchWindow[x,α] is equal to
. - WelchWindow[x] is equivalent to WelchWindow[x,1].
- WelchWindow automatically threads over lists.
Examples
open all close allBasic Examples (3)
Plot[WelchWindow[x], {x, -1, 1}]Plot3D[WelchWindow[x]WelchWindow[y], {x, -1, 1}, {y, -1, 1}, PlotRange -> All, Exclusions -> None]Extract the continuous function representing the Welch window:
FunctionExpand[WelchWindow[x]]FunctionExpand[WelchWindow[x, α]]Scope (6)
WelchWindow[0.1]Shape of a 1D Welch window using a specified parameter:
Plot[WelchWindow[x, 1.2], {x, -1, 1}, Exclusions -> None]Variation of the shape as a function of the parameter α:
Plot3D[WelchWindow[x, α], {α, 1, 5}, {x, -1, 1}, Exclusions -> None]Translated and dilated Welch window:
Plot[WelchWindow[(x - 1) / 2], {x, -1, 3}]2D Welch window with a circular support:
Plot3D[WelchWindow[Sqrt[x ^ 2 + y ^ 2]], {x, -1, 1}, {y, -1, 1}, PlotRange -> All, Exclusions -> None]Discrete Welch window of length 15:
ListPlot[Array[WelchWindow, 15, {-1 / 2, 1 / 2}], Filling -> Axis]Discrete 15×10 2D Welch window:
ListPointPlot3D[Array[WelchWindow[#1] WelchWindow[#2]&, {15, 10}, {{-1 / 2, 1 / 2}}], Filling -> Axis]Applications (3)
Create a moving-average filter of length 11:
h = ConstantArray[1 / 11., 11]Taper the filter using a Welch window:
w = Array[WelchWindow, 11, {-1 / 2, 1 / 2}];
fir = w h / Total[w h];Log-magnitude plot of the power spectra of the filters:
Plot[Evaluate[20Log10[Abs@ListFourierSequenceTransform[#, ω]]& /@ {h, fir}], {ω, 0.1, Pi}, GridLines -> Automatic]Use a window specification to calculate sample PowerSpectralDensity:
proc = ARMAProcess[1, {.5}, {.3}, 1];
data = RandomFunction[proc, {50}];spec = PowerSpectralDensity[data, w, WelchWindow];Compare to spectral density calculated without a windowing function:
sd = PowerSpectralDensity[data, w];sd === specThe plot shows that the window smooths the spectral density:
Plot[{sd, spec}, {w, -π, π}, PlotRange -> All, PlotLegends -> {"no window", "with window"}]Compare to the theoretical spectral density of the process:
Plot[{spec, Evaluate@PowerSpectralDensity[proc, w]}, {w, -π, π}, PlotLegends -> {"data", "process"}]Use a window specification for time series estimation:
data = RandomFunction[ARMAProcess[1, {.3}, {.4}, 1], {300}];Specify window for spectral estimator:
EstimatedProcess[data, ARMAProcess[1, 1], ProcessEstimator -> {"SpectralEstimator", "Window" -> WelchWindow}]Properties & Relations (2)
The area under the Welch window:
area = Integrate[WelchWindow[x], {x, -∞, ∞}]Normalize to create a window with unit area:
Plot[{WelchWindow[x], WelchWindow[x] / area}, {x, -1, 1}, PlotRange -> All]Fourier transform of the Welch window:
f = FourierTransform[WelchWindow[x], x, w]Power spectrum of the Welch window:
LogLinearPlot[20 Log[10, Abs[f]], {w, .1, 100}]Possible Issues (1)
2D sampling of Welch window will use a different parameter for each row of samples when passed as a symbol to Array:
Array[WelchWindow, {30, 30}, {{-1 / 2, 1 / 2}}]//ListPlot3DArray[WelchWindow[#1] WelchWindow[#2]&, {30, 30}, {{-1 / 2, 1 / 2}}]//ListPlot3DRelated Guides
History
Text
Wolfram Research (2012), WelchWindow, Wolfram Language function, https://reference.wolfram.com/language/ref/WelchWindow.html.
CMS
Wolfram Language. 2012. "WelchWindow." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/WelchWindow.html.
APA
Wolfram Language. (2012). WelchWindow. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/WelchWindow.html
BibTeX
@misc{reference.wolfram_2026_welchwindow, author="Wolfram Research", title="{WelchWindow}", year="2012", howpublished="\url{https://reference.wolfram.com/language/ref/WelchWindow.html}", note=[Accessed: 13-June-2026]}
BibLaTeX
@online{reference.wolfram_2026_welchwindow, organization={Wolfram Research}, title={WelchWindow}, year={2012}, url={https://reference.wolfram.com/language/ref/WelchWindow.html}, note=[Accessed: 13-June-2026]}