Abstract
Linear time-invariant systems have been studied by using both the frequency domain method and the state space method. However, there has been little effort devoted to comparing the characteristic features of these two methods.
This paper is concerned with one of such problems that have been left aside. The problem is to explain the difference between the effect of state variable feedback and the effect of output feedback using a compensating element. The compensating element is so chosen that the closed-loop transfer function of the output feedback system is identical with that of the optimal regulator with state variable feedback. It is shown that the output feedback system is quite different from the system with state variable feedback and therefore the effects of these two ways of feedback are distinct from each other.
