dlti — SciPy v1.15.3 Manual (original) (raw)

scipy.signal.

class scipy.signal.dlti(*system, **kwargs)[source]#

Discrete-time linear time invariant system base class.

Parameters:

*system: arguments

The dlti class can be instantiated with either 2, 3 or 4 arguments. The following gives the number of arguments and the corresponding discrete-time subclass that is created:

• 2: TransferFunction: (numerator, denominator)
• 3: ZerosPolesGain: (zeros, poles, gain)
• 4: StateSpace: (A, B, C, D)

Each argument can be an array or a sequence.

dt: float, optional

Sampling time [s] of the discrete-time systems. Defaults to True(unspecified sampling time). Must be specified as a keyword argument, for example, dt=0.1.

Notes

dlti instances do not exist directly. Instead, dlti creates an instance of one of its subclasses: StateSpace, TransferFunction orZerosPolesGain.

Changing the value of properties that are not directly part of the current system representation (such as the zeros of a StateSpace system) is very inefficient and may lead to numerical inaccuracies. It is better to convert to the specific system representation first. For example, callsys = sys.to_zpk() before accessing/changing the zeros, poles or gain.

If (numerator, denominator) 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]).

Added in version 0.18.0.

Examples

from scipy import signal

signal.dlti(1, 2, 3, 4) StateSpaceDiscrete( array([[1]]), array([[2]]), array([[3]]), array([[4]]), dt: True )

signal.dlti(1, 2, 3, 4, dt=0.1) StateSpaceDiscrete( array([[1]]), array([[2]]), array([[3]]), array([[4]]), dt: 0.1 )

Construct the transfer function\(H(z) = \frac{5(z - 1)(z - 2)}{(z - 3)(z - 4)}\) with a sampling time of 0.1 seconds:

signal.dlti([1, 2], [3, 4], 5, dt=0.1) ZerosPolesGainDiscrete( array([1, 2]), array([3, 4]), 5, dt: 0.1 )

Construct the transfer function \(H(z) = \frac{3z + 4}{1z + 2}\) with a sampling time of 0.1 seconds:

signal.dlti([3, 4], [1, 2], dt=0.1) TransferFunctionDiscrete( array([3., 4.]), array([1., 2.]), dt: 0.1 )

Attributes:

dt

Return the sampling time of the system.

poles

Poles of the system.

zeros

Zeros of the system.

Methods