Module « scipy.signal »

Classe « TransferFunction »

Informations générales

Héritage

builtins.object
    LinearTimeInvariant
        TransferFunction

Définition

class TransferFunction(LinearTimeInvariant):

Description _{[extrait de TransferFunction.__doc__]}

Linear Time Invariant system class in transfer function form.

    Represents the system as the continuous-time transfer function
    :math:`H(s)=\sum_{i=0}^N b[N-i] s^i / \sum_{j=0}^M a[M-j] s^j` or the
    discrete-time transfer function
    :math:`H(s)=\sum_{i=0}^N b[N-i] z^i / \sum_{j=0}^M a[M-j] z^j`, where
    :math:`b` are elements of the numerator `num`, :math:`a` are elements of
    the denominator `den`, and ``N == len(b) - 1``, ``M == len(a) - 1``.
    `TransferFunction` systems inherit additional
    functionality from the `lti`, respectively the `dlti` classes, depending on
    which system representation is used.

    Parameters
    ----------
    *system: arguments
        The `TransferFunction` class can be instantiated with 1 or 2
        arguments. The following gives the number of input arguments and their
        interpretation:

            * 1: `lti` or `dlti` system: (`StateSpace`, `TransferFunction` or
              `ZerosPolesGain`)
            * 2: array_like: (numerator, denominator)
    dt: float, optional
        Sampling time [s] of the discrete-time systems. Defaults to `None`
        (continuous-time). Must be specified as a keyword argument, for
        example, ``dt=0.1``.

    See Also
    --------
    ZerosPolesGain, StateSpace, lti, dlti
    tf2ss, tf2zpk, tf2sos

    Notes
    -----
    Changing the value of properties that are not part of the
    `TransferFunction` system representation (such as the `A`, `B`, `C`, `D`
    state-space matrices) is very inefficient and may lead to numerical
    inaccuracies.  It is better to convert to the specific system
    representation first. For example, call ``sys = sys.to_ss()`` before
    accessing/changing the A, B, C, D system matrices.

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

    Examples
    --------
    Construct the transfer function
    :math:`H(s) = \frac{s^2 + 3s + 3}{s^2 + 2s + 1}`:

    >>> from scipy import signal

    >>> num = [1, 3, 3]
    >>> den = [1, 2, 1]

    >>> signal.TransferFunction(num, den)
    TransferFunctionContinuous(
    array([1., 3., 3.]),
    array([1., 2., 1.]),
    dt: None
    )

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

    >>> signal.TransferFunction(num, den, dt=0.1)
    TransferFunctionDiscrete(
    array([1., 3., 3.]),
    array([1., 2., 1.]),
    dt: 0.1
    )

    

Constructeur(s)

Signature du constructeur	Description
__new__(cls, *system, **kwargs)	Handle object conversion if input is an instance of lti. [extrait de __new__.__doc__]
__init__(self, *system, **kwargs)	Initialize the state space LTI system. [extrait de __init__.__doc__]

Liste des opérateurs

Opérateurs hérités de la classe object

__eq__, __ge__, __gt__, __le__, __lt__, __ne__

Méthodes héritées de la classe LinearTimeInvariant

__init_subclass__, __subclasshook__

Méthodes héritées de la classe object

__delattr__, __dir__, __format__, __getattribute__, __hash__, __reduce__, __reduce_ex__, __setattr__, __sizeof__, __str__