scipy.signal.TransferFunction

class scipy.signal.TransferFunction(*system)

Linear Time Invariant system class in transfer function form.

Represents the system as the transfer function \(H(s)=\sum_i b[i] s^i / \sum_j a[j] s^i\), where \(a\) are elements of the numerator num and \(b\) are the elements of the denominator den.

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 or ZerosPolesGain)
• 2: array_like: (numerator, denominator)

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.

Attributes

A	A matrix of the StateSpace system.
B	B matrix of the StateSpace system.
C	C matrix of the StateSpace system.
D	D matrix of the StateSpace system.
den
gain	Gain of the ZerosPolesGain system.
num
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.