Module « scipy.signal »

Fonction dbode - module scipy.signal

Signature de la fonction dbode

def dbode(system, w=None, n=100) 

Description

dbode.__doc__

    Calculate Bode magnitude and phase data of a discrete-time system.

    Parameters
    ----------
    system : an instance of the LTI class or a tuple describing the system.
        The following gives the number of elements in the tuple and
        the interpretation:

            * 1 (instance of `dlti`)
            * 2 (num, den, dt)
            * 3 (zeros, poles, gain, dt)
            * 4 (A, B, C, D, dt)

    w : array_like, optional
        Array of frequencies (in radians/sample). Magnitude and phase data is
        calculated for every value in this array. If not given a reasonable
        set will be calculated.
    n : int, optional
        Number of frequency points to compute if `w` is not given. The `n`
        frequencies are logarithmically spaced in an interval chosen to
        include the influence of the poles and zeros of the system.

    Returns
    -------
    w : 1D ndarray
        Frequency array [rad/time_unit]
    mag : 1D ndarray
        Magnitude array [dB]
    phase : 1D ndarray
        Phase array [deg]

    Notes
    -----
    If (num, den) is passed in for ``system``, coefficients for both the
    numerator and denominator should be specified in descending exponent
    order (e.g. ``z^2 + 3z + 5`` would be represented as ``[1, 3, 5]``).

    .. versionadded:: 0.18.0

    Examples
    --------
    >>> from scipy import signal
    >>> import matplotlib.pyplot as plt

    Construct the transfer function :math:`H(z) = \frac{1}{z^2 + 2z + 3}` with
    a sampling time of 0.05 seconds:

    >>> sys = signal.TransferFunction([1], [1, 2, 3], dt=0.05)

    Equivalent: sys.bode()

    >>> w, mag, phase = signal.dbode(sys)

    >>> plt.figure()
    >>> plt.semilogx(w, mag)    # Bode magnitude plot
    >>> plt.figure()
    >>> plt.semilogx(w, phase)  # Bode phase plot
    >>> plt.show()