Question

4. (4 Marks) The linear model of a phase detector (phase-lock-loop) can be represented by figure 4. Voltage-controlled oscillator Amplifier Filter LE Figure 4 Phase locked loop The phase-lock systems are designed to maintain zero difference in phase betweer the input carrier signal and a local voltage controlled oscillator. Phase lock loops find application in colour television, missile tracking and space telemetry. The filter for a particular application is chosen as: 10(s +10) (s +D(s +100) F(s) It is desired to minimize the steady state error of the system for a ramp change in the phase information signal. (a) Determine the value of the gain Kg-K in order to maintain a stable system. (b) It is decided that a steady state error equal to 1° is acceptable for a ramp signal of 100 rad/s. For that value of gain K , determine the location of the rools of the system. [Dorfl)

Answer 1

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