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The asymptotic Bode plot of the transfer function K is given in the figure. 1 + s 2
The error in the phase angle and dB gain at a frequency of ω = 0.5 a are respectively
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- 4.06° , 0.97 dB
- 5.7° , 3 dB
- 4.9° , 3 dB
- 5.7° , 0.97 dB
Correct Option: A
| ∠ GH |ω = 0.5a = -tan-1 | ||
| a |
= – tan– 1 0.5 = 26.56°
From the plot, at ω = 0, ∠ G(s) = 22.5°
∴ Error = – 22.50° (– 26.56°) = 4.06°
At ω = 0
20 log | GH| = 20 log k – 20 log | 1 + j 0.5|
= 20 log k – 0.97
From the plot, 20 log | GH| = 20 log k
∴ Error in dB gain = 0.97 dB
