134. Closed loop poles are

A. zeros of G(s) H(s)

B. pole of G(s) H(s)

C. zeros of 1 + G(s) H(s)

D. pole of 1 + G(s) H(s)

135. Which of the following technique is not applicable to nonlinear system ?

A. functional analysis

B. Nyquist criterion

C. Quasi linearization

D. phase-plane representation

136. Backlash in a stable control system may cause:

A. underdamping

B. overdamping

C. low level oscillations

D. high level

137. Saturation in a stable control system may cause

A. overdamping

B. conditional stability

C. low level oscillations

D. high level oscillations

138. Noise in a control system can be kept low by

A. reducing the bandwidth

B. attenuating such frequencies at which external signals get coupled into the system

C. both A and B above

D. none of the above

139. Excessive noise in a control system may result in

A. reduction in gain

B. reduction in bandwidth

C. oscillations

D. saturation in amplifying stages

140. For a closed loop system to be stable, the Nyquist plot of G (s) H (s) must encircle the point (-1, j0) as many time as the number of

A. zeros of G(s) H(s) in the RHS of s-plane

B. zeros of G(s) H(s) in the LHS of s-plane

C. poles of G(s) H(s) in the RHS of s-plane

D. poles of G(s) H(s) in the LHS of s-plane

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