Question

The transfer function is applicable to which of the following?

(a) Linear and time-in variant systems

(b) Linear and time-variant systems

(c) Linear systems

(d) Non-linear systems

I have been asked this question at a job interview.

Origin of the question is Constructing  Phase-Trajectories topic in chapter Nonlinear Systems of Control Systems

Answer 1

The correct answer is (a) Linear and time-in variant systems

The best I can explain: The transfer function is different from the state space approach as the transfer function approach is similar to the LTI systems only while the state variable analysis is applicable to the non-linear time variant systems also.