Electronics and Communication Engineering - Automatic Control Systems

46.
The system in the given figure, has
good gain and phase margin
poor gain and phase margin
good gain margin but poor phase margin
poor gain margin but good phase margin
Answer: Option
Explanation:

Since the plot is very near (-1 + j0) point, gain margin is poor.


47.
The given figure shows a pole zero diagram. The transfer function G(j1) is
0.5 ∠0
2.7 ∠- 31°
2 ∠45°
2 ∠- 67.4°
Answer: Option
Explanation:

Join j1 point with the zero and poles. Find magnitude and phase angles of all these lines.


48.
For very low frequencies, v0/vi in the given figure equals
1
0
0.5
Answer: Option
Explanation:

For low frequencies Xc is very high as compared to R. Hence .


49.
In a minimum phase system
all poles lie in the left half plane
all zeros lie in the left half plane
all poles lie in the right half plane
all except one pole or zero lie in the left half plane
Answer: Option
Explanation:

For stability poles must be in left half plane. Zeros in left half plane lead to minimum phase shift.


50.
For the system of the given figure the transfer function is
Answer: Option
Explanation:

Transfer function = .