scipy.signal.TransferFunction¶
-
class
scipy.signal.
TransferFunction
(*system)[source]¶ Linear Time Invariant system class in transfer function form.
Represents the system as the transfer function \(H(s)=\sum_{i=0}^N b[N-i] s^i / \sum_{j=0}^M a[M-j] s^j\), where \(b\) are elements of the numerator
num
, \(a\) are elements of the denominatorden
, andN == len(b) - 1
,M == len(a) - 1
.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
system: (StateSpace
,TransferFunction
orZerosPolesGain
) - 2: array_like: (numerator, denominator)
See also
Notes
Changing the value of properties that are not part of the
TransferFunction
system representation (such as theA
,B
,C
,D
state-space matrices) is very inefficient and may lead to numerical inaccuracies.Examples
Construct the transfer function:
\[H(s) = \frac{s^2 + 3s + 3}{s^2 + 2s + 1}\]>>> from scipy import signal >>> num = [1, 3, 3] >>> den = [1, 2, 1] >>> signal.TransferFunction(num, den) TransferFunction( array([ 1., 3., 3.]), array([ 1., 2., 1.]) )
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.gain
Gain of the ZerosPolesGain
system.num
Numerator of the TransferFunction
system.poles
Poles of the ZerosPolesGain
system.zeros
Zeros of the ZerosPolesGain
system.Methods
bode
([w, n])Calculate Bode magnitude and phase data of a continuous-time system. freqresp
([w, n])Calculate the frequency response of a continuous-time system. impulse
([X0, T, N])Return the impulse response of a continuous-time system. output
(U, T[, X0])Return the response of a continuous-time system to input U. step
([X0, T, N])Return the step response of a continuous-time system. to_ss
()Convert system representation to StateSpace
.to_tf
()Return a copy of the current TransferFunction
system.to_zpk
()Convert system representation to ZerosPolesGain
.- 1: