Module « scipy.signal »

Fonction ss2tf - module scipy.signal

Signature de la fonction ss2tf

def ss2tf(A, B, C, D, input=0) 

Description

ss2tf.__doc__

State-space to transfer function.

    A, B, C, D defines a linear state-space system with `p` inputs,
    `q` outputs, and `n` state variables.

    Parameters
    ----------
    A : array_like
        State (or system) matrix of shape ``(n, n)``
    B : array_like
        Input matrix of shape ``(n, p)``
    C : array_like
        Output matrix of shape ``(q, n)``
    D : array_like
        Feedthrough (or feedforward) matrix of shape ``(q, p)``
    input : int, optional
        For multiple-input systems, the index of the input to use.

    Returns
    -------
    num : 2-D ndarray
        Numerator(s) of the resulting transfer function(s). `num` has one row
        for each of the system's outputs. Each row is a sequence representation
        of the numerator polynomial.
    den : 1-D ndarray
        Denominator of the resulting transfer function(s). `den` is a sequence
        representation of the denominator polynomial.

    Examples
    --------
    Convert the state-space representation:

    .. math::

        \dot{\textbf{x}}(t) =
        \begin{bmatrix} -2 & -1 \\ 1 & 0 \end{bmatrix} \textbf{x}(t) +
        \begin{bmatrix} 1 \\ 0 \end{bmatrix} \textbf{u}(t) \\

        \textbf{y}(t) = \begin{bmatrix} 1 & 2 \end{bmatrix} \textbf{x}(t) +
        \begin{bmatrix} 1 \end{bmatrix} \textbf{u}(t)

    >>> A = [[-2, -1], [1, 0]]
    >>> B = [[1], [0]]  # 2-D column vector
    >>> C = [[1, 2]]    # 2-D row vector
    >>> D = 1

    to the transfer function:

    .. math:: H(s) = \frac{s^2 + 3s + 3}{s^2 + 2s + 1}

    >>> from scipy.signal import ss2tf
    >>> ss2tf(A, B, C, D)
    (array([[1., 3., 3.]]), array([ 1.,  2.,  1.]))