Module « scipy.signal »

Fonction tukey - module scipy.signal

Signature de la fonction tukey

def tukey(*args, **kwargs) 

Description

tukey.__doc__

Return a Tukey window, also known as a tapered cosine window.

    .. warning:: scipy.signal.tukey is deprecated,
                 use scipy.signal.windows.tukey instead.

    Parameters
    ----------
    M : int
        Number of points in the output window. If zero or less, an empty
        array is returned.
    alpha : float, optional
        Shape parameter of the Tukey window, representing the fraction of the
        window inside the cosine tapered region.
        If zero, the Tukey window is equivalent to a rectangular window.
        If one, the Tukey window is equivalent to a Hann window.
    sym : bool, optional
        When True (default), generates a symmetric window, for use in filter
        design.
        When False, generates a periodic window, for use in spectral analysis.

    Returns
    -------
    w : ndarray
        The window, with the maximum value normalized to 1 (though the value 1
        does not appear if `M` is even and `sym` is True).

    References
    ----------
    .. [1] Harris, Fredric J. (Jan 1978). "On the use of Windows for Harmonic
           Analysis with the Discrete Fourier Transform". Proceedings of the
           IEEE 66 (1): 51-83. :doi:`10.1109/PROC.1978.10837`
    .. [2] Wikipedia, "Window function",
           https://en.wikipedia.org/wiki/Window_function#Tukey_window

    Examples
    --------
    Plot the window and its frequency response:

    >>> from scipy import signal
    >>> from scipy.fft import fft, fftshift
    >>> import matplotlib.pyplot as plt

    >>> window = signal.windows.tukey(51)
    >>> plt.plot(window)
    >>> plt.title("Tukey window")
    >>> plt.ylabel("Amplitude")
    >>> plt.xlabel("Sample")
    >>> plt.ylim([0, 1.1])

    >>> plt.figure()
    >>> A = fft(window, 2048) / (len(window)/2.0)
    >>> freq = np.linspace(-0.5, 0.5, len(A))
    >>> response = 20 * np.log10(np.abs(fftshift(A / abs(A).max())))
    >>> plt.plot(freq, response)
    >>> plt.axis([-0.5, 0.5, -120, 0])
    >>> plt.title("Frequency response of the Tukey window")
    >>> plt.ylabel("Normalized magnitude [dB]")
    >>> plt.xlabel("Normalized frequency [cycles per sample]")