Module « scipy.signal »

Fonction nuttall - module scipy.signal

Signature de la fonction nuttall

def nuttall(*args, **kwargs) 

Description

nuttall.__doc__

Return a minimum 4-term Blackman-Harris window according to Nuttall.

    This variation is called "Nuttall4c" by Heinzel. [2]_

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

    Parameters
    ----------
    M : int
        Number of points in the output window. If zero or less, an empty
        array is returned.
    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] A. Nuttall, "Some windows with very good sidelobe behavior," IEEE
           Transactions on Acoustics, Speech, and Signal Processing, vol. 29,
           no. 1, pp. 84-91, Feb 1981. :doi:`10.1109/TASSP.1981.1163506`.
    .. [2] Heinzel G. et al., "Spectrum and spectral density estimation by the
           Discrete Fourier transform (DFT), including a comprehensive list of
           window functions and some new flat-top windows", February 15, 2002
           https://holometer.fnal.gov/GH_FFT.pdf

    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.nuttall(51)
    >>> plt.plot(window)
    >>> plt.title("Nuttall window")
    >>> plt.ylabel("Amplitude")
    >>> plt.xlabel("Sample")

    >>> 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 Nuttall window")
    >>> plt.ylabel("Normalized magnitude [dB]")
    >>> plt.xlabel("Normalized frequency [cycles per sample]")