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Fonction decimate - module scipy.signal

Signature de la fonction decimate

def decimate(x, q, n=None, ftype='iir', axis=-1, zero_phase=True) 

Description

decimate.__doc__

    Downsample the signal after applying an anti-aliasing filter.

    By default, an order 8 Chebyshev type I filter is used. A 30 point FIR
    filter with Hamming window is used if `ftype` is 'fir'.

    Parameters
    ----------
    x : array_like
        The signal to be downsampled, as an N-dimensional array.
    q : int
        The downsampling factor. When using IIR downsampling, it is recommended
        to call `decimate` multiple times for downsampling factors higher than
        13.
    n : int, optional
        The order of the filter (1 less than the length for 'fir'). Defaults to
        8 for 'iir' and 20 times the downsampling factor for 'fir'.
    ftype : str {'iir', 'fir'} or ``dlti`` instance, optional
        If 'iir' or 'fir', specifies the type of lowpass filter. If an instance
        of an `dlti` object, uses that object to filter before downsampling.
    axis : int, optional
        The axis along which to decimate.
    zero_phase : bool, optional
        Prevent phase shift by filtering with `filtfilt` instead of `lfilter`
        when using an IIR filter, and shifting the outputs back by the filter's
        group delay when using an FIR filter. The default value of ``True`` is
        recommended, since a phase shift is generally not desired.

        .. versionadded:: 0.18.0

    Returns
    -------
    y : ndarray
        The down-sampled signal.

    See Also
    --------
    resample : Resample up or down using the FFT method.
    resample_poly : Resample using polyphase filtering and an FIR filter.

    Notes
    -----
    The ``zero_phase`` keyword was added in 0.18.0.
    The possibility to use instances of ``dlti`` as ``ftype`` was added in
    0.18.0.