Below is the schematic of a low pass filter The transfer fun

Below is the schematic of a low pass filter. The transfer function is: H(s) = 10 314k^2/(s + 314k)^2 As can be seen from the following bode plot, the transfer functions of the circuit and the ideal transfer function in the frequency domain match. Unfortunately they do not match in the time domain when the input is u(t). Why do they not match? What is the \"cure\"?

Solution

System time response is different from frequency response. A system time response will show how the system will respond when it is disturbed or an input is applied or changed suddenly. Here if you observe the 2^nd plot representing how the system is attaining its steady state or a final value with respect to time.

Where as in frequency response will tell us how the ratio of output to input under steady state is changing when the frequency of the input is changing where the input signal is sinusoidal.

So these two figures are related to system but in different domines.