Signal Processing Stack Exchange
Signal Processing Stack Exchange

Questions tagged [window-functions]

In signal processing, a window function is a mathematical function that is zero-valued outside of some chosen interval.

For instance, a function that is constant inside the interval and zero elsewhere is called a rectangular window, which describes the shape of its graphical representation. When another function or a signal (data) is multiplied by a window function, the product is also zero-valued outside the interval: all that is left is the part where they overlap; the "view through the window". Applications of window functions include spectral analysis, filter design, and beamforming.

Source: Window function

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A few questions about Slepian and generalized gaussian windows

I'm trying to add documentation for all the window functions in scipy.signal, and I'm stuck on the Slepian (same as DPSS?) and Generalized Gaussian windows, which I'd never heard of before. There are two variables that are shape parameters of some…
endolith
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How do I apply a function window to a signal?

How can I apply a window function like Hamming or Lanczos to a signal, using its coefficients? I mean, which method can I use to do this? FFT? Convolution? Which method has the better performance?
walteram
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Complex Windows

Typically windows are symmetrical and real. Are there any applications where complex windows have been used (other than applying the same real window to the real and imaginary components of a complex number). A full complex window would have the…
Dan Boschen
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How does a rectangular window affect the signal?

If i am not mistaken a rectangular window of length 10 gives us an array of 10x1: 1 1 1 1 1 1 1 1 1 1 And if we apply this to a signal we are left with exactly what we started with as: x = x*1 So how does a rectangular window improve or do…
Niklas
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Taylor Window Algorithm

I am trying to find out the algorithm for taylor window function but i have looked everywhere and i dont see any proper algorithm. I read it is similar to Kaiser Window but thats all I know. Can someone help me find the algorithm?
Shubham Kapoor
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Dropping the zeros at the edge of window functions

I have learned that Scipy's implementation of the Hann window allows receiving both a symmetric window, and a periodic window (meaning the last zero element is dropped). As far as I understand, the periodic window is preferable for the DFT as it has…
Gideon Genadi Kogan
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Measure scalloping loss of window function

Is there an easy/general way to calculate this? For instance, the rectangular window has a maximum scalloping loss of 0.3634, which can be derived in frequency domain from a normalized sinc(0.5). The only way, given a precomputed window function, I…
Shaggi
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Plot of the Fourier transform of the Sine Window

In Wikipedia, a Fourier transform of the Sine Window \begin{align} w[n] = \sin \left(\frac{\pi n}{N} \right), \ 0\leq n \leq N \end{align} is plotted like below. However, I am not sure how to obtain this plot. The Fourier transform of the sine…
Ogiad
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spectral leakage for integral number of periods

I'm attempting to understand spectral leakage and read the following quote on wikipedia: Windowing a sinusoid causes spectral leakage, even if the sinusoid has an integer number of cycles within a rectangular window. This confuses me, since I…
MattHusz
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Cosine window function & signal with nonzero mean

I'm using cosine window function of order $p$: $$ f(t) = \frac{2^p (p!)^2}{(2 p!)} \left(1 + \cos(\pi t)\right)^p $$ for frequency identification in real signals with several frequency components. For a simple test signal $ s(t) = 0.1 + \sin(2 \pi…
I.M.
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how could window function really suppress those frequencies that we don't want?

I know we can use window function to decrease leakage phenomenon by making the end of a non-periodic signal to be zero at both end, so that to make it like "continuous and periodic" when doing fft. However, when we multiply window function with…
Yui
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Running window maximum: Any cautions?

Are there any statistical concerns with using a running-window maximum to capture peak values? Background: We are measuring acceleration during random impacts on a structure. The impacts need ~500Hz sampling to resolve, but due to data volume I can…
KAE
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Apply the Hamming window to a sinusoidal signal

I am a novice in signal processing. I am writing a code to apply the hamming window to a sinusoidal signal. So first I have digitized my sinusoidal signal by choosing a sampling rate more than twice its frequency. These are the values for the…
Jack
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Where do we use windowing?

I have been studying about the box window and am unable to understand one thing, do we first sample a signal and then window it resulting in up-scaling or downscaling, or is windowing a practical case of sampling itself which is performed on a…
ubuntu_noob
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Applying Hanning window $w_n=1-\cos\Big(\frac{2\pi n}{N}\Big)$ to data

I have a time-series data file in python and I am asked to apply a Hanning window $w_n=1-\cos\Big(\frac{2\pi n}{N}\Big), 0\leq n\leq N=\text{file length}$ to the data given. I am very new to this subject so I have no idea how to apply this window…
LianNuo
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