Electronics and Communication Engineering - Exam Questions Papers

26. 

For the asymptotic Bode magnitude plot shown below, the system transfer function can be

A.
B.
C.
D.

Answer: Option A

Explanation:

.


27. 

A square in which each (i, j)th element of matrix is equal to the negative of the conjugate complex of (j, i)th element, is called

A. Hermitian matrix
B. Skew symmetric matrix
C. Conjugate anti-symmetric matrix
D. Skew-Hermitian matrix

Answer: Option D

Explanation:

When aij = - .

This matrix is called skew hermitian matrix.


28. 


Mid-band gain =

A. 100
B. - 100
C. 50
D. - 50

Answer: Option B

Explanation:

.


29. 

The characteristic equation of a feedback control system is given by s3 + 5s2 + (K + 6)s + K = 0
where K > 0 is a scalar variable parameter. In the root-loci diagram of the system the asymptotes of the root-locus for large values of K meet at a point in the s-plane, whose coordinates are :

A. (- 3, 0)
B. (- 2, 0)
C. (- 1, 0)
D. (2, 0)

Answer: Option C

Explanation:

Apply R-H, and find ω by auxiliary equation.


30. 

The input 3-dB frequency is :

A. 100 Hz
B. 148 Hz
C. 100 kHz
D. None

Answer: Option B

Explanation:

Input 3 dB frequency

C = 0.40 μF.