scipy.signal.

get_window

scipy.signal.get_window(window, Nx, fftbins=True, *, xp=None, device=None)

Convenience function for creating various windows.

This function is a wrapper for the window functions provided in the scipy.signal.windows namespace.

Parameters:

windowstr | tuple | float

Either a string with the window name or a tuple consisting of window name and window parameters. If it is a float, a kaiser window is created with window being the shape parameter. Consult the Notes below for more details.

Nxint

The number of samples in the window.

fftbinsbool, optional

If True (default), create a periodic window, ready to use with ifftshift and be multiplied by the result of an FFT (see also fftfreq). If False, create a symmetric window, for use in filter design. This parameter is ignored, if the window name in the window parameter has a suffix '_periodic' or '_symmetric' appended to it (e.g., 'hann_symmetric').

xparray_namespace, optional

Optional array namespace. Should be compatible with the array API standard, or supported by array-api-compat. Default: numpy

device: any

optional device specification for output. Should match one of the supported device specification in xp.

Returns:

get_windowndarray

Returns the created window as a one-dimensional array made of Nx samples.

Raises:

ValueError

If the provided parameters do not allow to choose a valid window function with valid parameters.

Notes

Note that by default this function returns a periodic window, whereas the wrapped window functions return a symmetric window by default. This is caused by the fftbins parameter having the inverse meaning of the sym parameter of the wrapped function, which are both True by default.

The following list shows the wrapped window functions with the respective settings of the window parameter followed by a short description. Aliases for alternative window names are given in parenthesis.

barthann / 'barthann':

Modified Bartlett-Hann window (aliases: 'brthan', 'bth')

bartlett / 'bartlett':

Bartlett window (aliases: 'bart', 'brt')

blackman/ 'blackman':

Blackman window (aliases: 'black', 'blk')

blackmanharris / 'blackmanharris':

4-term Blackman-Harris window (aliases: 'blackharr', 'bkh')

bohman / 'bohman':

Bohman window (aliases: 'bman', 'bmn')

boxcar / 'boxcar':

Rectangular window (aliases: 'box', 'ones', 'rect', 'rectangular')

chebwin / ('chebwin', at):

Dolph-Chebyshev window with at dB attenuation (aliases: 'cheb')

cosine / 'cosine':

Cosine window (aliases: 'halfcosine')

dpss / ('dpss', NW):

First window of discrete prolate spheroidal sequence with standardized half bandwidth NW and “approximate” norm.

exponential / 'exponential' / ('exponential', center, tau):

Exponential / Poisson window centered at center (default: None) with deacy tau (default: 1) (aliases: 'poisson')

flattop/ 'flattop':

Flat top window (aliases: 'flat', 'flt')

gaussian / ('gaussian', std):

Gaussian with standard deviation std (aliases: 'gauss', 'gss')

general_cosine / ('general cosine', a):

Generic weighted sum of cosine terms with weighting coefficients a (aliases: 'general_cosine')

general_gaussian / ('general gaussian', p, sig):

Generalized Gaussian with shape parameter p and standard deviation sig (aliases: 'general_gaussian', 'general gauss', 'general_gauss', 'ggs')

general_hamming / ('general hamming', alpha):

Generalized Hamming window with coefficent alpha (aliases: 'general_hamming')

hamming / 'hamming':

Hamming window (aliases: 'hamm', 'ham')

hann / 'hann':

Hann window (aliases: 'han')

kaiser / ('kaiser', beta):

Kaiser window with shape parameter beta (aliases: 'ksr')

kaiser_bessel_derived / ('kaiser bessel derived', beta):

Kaiser-Bessel derived window with shape parameter beta (aliases: 'kaiser_bessel_derived', 'kbd')

lanczos / 'lanczos':

Lanczos / sinc window (aliases: 'sinc')

nuttall/ 'nuttall':

Minimum 4-term Blackman-Harris window according to Nuttall (aliases: 'nutl', 'nut')

parzen / 'parzen':

Parzen window (aliases: 'parz', 'par')

taylor / 'taylor' / ('taylor', nbar, sll, norm):

Taylor window with nbar adjascent sidelobes (default: 4)), sll dB suppression level (default: 30) and boolean value norm (default: True) (aliases: taylorwin)

triang/ 'triangle':

Triangle window (aliases: 'triang', 'tri')

tukey / 'tukey' / ('tukey', alpha):

Tukey window with shape parameter alpha (default: 0.5) (aliases: 'tuk')

Examples

Try it in your browser!

This example shows different usages of the window parameter:

>>> from scipy.signal import get_window
>>> get_window('triang', 7)
array([ 0.125,  0.375,  0.625,  0.875,  0.875,  0.625,  0.375])
>>> get_window(('exponential', None, 1.), 9)
array([ 0.011109  ,  0.03019738,  0.082085  ,  0.22313016,  0.60653066,
        0.60653066,  0.22313016,  0.082085  ,  0.03019738])
>>> get_window(('kaiser', 4.0), 9)
array([ 0.08848053,  0.29425961,  0.56437221,  0.82160913,  0.97885093,
        0.97885093,  0.82160913,  0.56437221,  0.29425961])
>>> get_window(4.0, 9)  # same as previous call
array([ 0.08848053,  0.29425961,  0.56437221,  0.82160913,  0.97885093,
        0.97885093,  0.82160913,  0.56437221,  0.29425961])

The following snippet shows different ways to create identical symmetric and periodic Bartlett windows:

>>> from scipy.signal import get_window, windows
>>> # Symmetric window:
>>> windows.bartlett(5)  # Parameter `sym` defaults to True
array([0. , 0.5, 1. , 0.5, 0. ])
>>> get_window('bartlett', 5, fftbins=False)
array([0. , 0.5, 1. , 0.5, 0. ])
>>> get_window('bartlett_symmetric', 5)
array([0. , 0.5, 1. , 0.5, 0. ])
>>> # Periodic window:
>>> windows.bartlett(4, sym=False)
array([0. , 0.5, 1. , 0.5])
>>> get_window('bartlett', 4)  # Parameter `fftbins` defaults to True
array([0. , 0.5, 1. , 0.5])
>>> get_window('bartlett_periodic', 4)
array([0. , 0.5, 1. , 0.5])
>>> # `_periodic' suffix overrides `fftbins` parameter:
>>> get_window('bartlett_periodic', 4, fftbins=False)
array([0. , 0.5, 1. , 0.5])

Note that a periodic window can be created out of a symmetric window by discarding the last sample.

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