For a gain of 0.5, derive the gain margin and phase margin of the systems of Problem 4.6 analytically. Let T =5 1 with no loss of generality because the value of ωT in radians is all that is needed for the solution. Explain why the phase margin is not defined for the system shown inProblem 4.6(a). Hint: The gain margin is obtained by finding the point where the imaginary part of the frequency response is zero. The phase margin is obtained by finding the point where the magnitude of the frequency response is unity.
Problem 4.6
Use the Routh-Hurwitz criterion to find the stable range of K for the closed-loop unity feedback systems ith loop gain
