# 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 $$H(s)=\sum_i b[i] s^i / \sum_j a[j] s^i$$, 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.

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