For this, the amplitude response and the phase response are determined from the transfer function of the system and plotted as a graph with the gain and the phase as a function of frequency. This is called the frequency response of the system. For the development of dynamic systems in electrical engineering, control engineering, and even mechatronics, the steady-state response at the output of the system to harmonic excitation (sinusoidal oscillation) at the input often must be known.