StateSpace.__call__(x, squeeze=None, warn_infinite=True)[source]

Evaluate system’s frequency response at complex frequencies.

Returns the complex frequency response sys(x) where x is s for continuous-time systems and z for discrete-time systems.

To evaluate at a frequency omega in radians per second, enter x = omega * 1j, for continuous-time systems, or x = exp(1j * omega * dt) for discrete-time systems. Or use StateSpace.frequency_response().

  • x (complex or complex 1D array_like) – Complex frequencies

  • squeeze (bool, optional) – If squeeze=True, remove single-dimensional entries from the shape of the output even if the system is not SISO. If squeeze=False, keep all indices (output, input and, if omega is array_like, frequency) even if the system is SISO. The default value can be set using config.defaults[‘control.squeeze_frequency_response’].

  • warn_infinite (bool, optional) – If set to False, don’t warn if frequency response is infinite.


fresp – The frequency response of the system. If the system is SISO and squeeze is not True, the shape of the array matches the shape of omega. If the system is not SISO or squeeze is False, the first two dimensions of the array are indices for the output and input and the remaining dimensions match omega. If squeeze is True then single-dimensional axes are removed.

Return type

complex ndarray