scipy.signal.lti¶

class
scipy.signal.
lti
(*system)[source]¶ Continuoustime linear time invariant system base class.
Parameters: *system : arguments
The
lti
class can be instantiated with either 2, 3 or 4 arguments. The following gives the number of arguments and the corresponding continuoustime 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.
See also
Notes
lti
instances do not exist directly. Instead,lti
creates an instance of one of its subclasses:StateSpace
,TransferFunction
orZerosPolesGain
.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
would be represented as[1, 3, 5]
).Changing the value of properties that are not directly part of the current system representation (such as the
zeros
of aStateSpace
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.Examples
>>> from scipy import signal
>>> signal.lti(1, 2, 3, 4) StateSpaceContinuous( array([[1]]), array([[2]]), array([[3]]), array([[4]]), dt: None )
>>> signal.lti([1, 2], [3, 4], 5) ZerosPolesGainContinuous( array([1, 2]), array([3, 4]), 5, dt: None )
>>> signal.lti([3, 4], [1, 2]) TransferFunctionContinuous( array([ 3., 4.]), array([ 1., 2.]), dt: None )
Attributes
A
State matrix of the StateSpace
system.B
Input matrix of the StateSpace
system.C
Output matrix of the StateSpace
system.D
Feedthrough matrix of the StateSpace
system.den
Denominator of the TransferFunction
system.dt
Return the sampling time of the system, None for lti
systems.gain
Gain of the ZerosPolesGain
system.num
Numerator of the TransferFunction
system.poles
Poles of the system. zeros
Zeros of the system. Methods
bode
([w, n])Calculate Bode magnitude and phase data of a continuoustime system. freqresp
([w, n])Calculate the frequency response of a continuoustime system. impulse
([X0, T, N])Return the impulse response of a continuoustime system. output
(U, T[, X0])Return the response of a continuoustime system to input U. step
([X0, T, N])Return the step response of a continuoustime system. to_discrete
(dt[, method, alpha])Return a discretized version of the current system.  2: