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The frequency response of a linear system G(jω) is provided in the tabular form below
| G(jω)| 1.3 1.2 1.0 0.8 0.5 0.3 ∠ G(jω) – 130° – 140° – 150° – 160° – 180° – 200°
The gain margin and phase margin of the system are
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- 6 dB and 30°
- 6 dB and – 30°
- – 6 dB and 30°
- – 6 dB and – 30°
Correct Option: A
At ∠ G(jω) = – 180, magnitude M = 0.5
| ∴ G.M = 20 log |  |  | = 6 dB | |
| 0.5 |
At | G(jω) | = 1, phase angle ∠ G(jω) = – 150
∴ P.M = 180 + (– 150) = 30°
