Direction: Read the following passages carefully and answer the question that follows.
Regardless of how the state's feedback control law is designed, it is almost always necessary to implement it, using estimates of the state obtained from an observer. Hence, it is necessary to insure so that the desirable properties of the state feedback design do not vanish when the state estimate are used. It is proven in linear system theory courses that the command response is unaffected by the presence of the observer. However, the response to initial conditions will affect the system output. It is suggested that the observed poles should be made faster than the state feedback poles by an amount that depends upon the level of measurement noise. These conclusions are generally based upon transient time response properties of the system, and not on feedback properties such as robustness margins, We now present a procedure for tuning an observer so that, under appropriate conditions, the feedback properties of a state feedback design are recovered.