Electronics and Communication Engineering - Signals and Systems

26. 

A function having frequency f is to be sampled. The sampling time T should be

A.
B.
C.
D.

Answer: Option C

Explanation:

Sampling frequency must be more than 2f. Therefore .


27. 

The final value theorem is

A.
B.
C.
D.

Answer: Option A

Explanation:

£f(t) =

£-1F(s) = f(t)

£[a f1(t) + bf2(t)] = aF1(s) + bF2(s)

where

£[f(t - T)] = e-sT F(s)

£[e-at f(t)] = F(s + a)

Initial value theorem

Final value theroem

Convolution Integral

where t is dummy variable for t.


28. 

If

A. - 12
B. 12
C. 20
D. - 20

Answer: Option A

Explanation:

det.|A| = 3(8 - 12) = - 12.


29. 

Inverse Fourier transform of sgn (ω) is

A.
B. 1
C. U(t)
D.

Answer: Option A

Explanation:

By duality Property.


30. 

If I (s) , the final value of i(t) is

A. 5A
B. 12.5 A
C. 0.05 A
D. 1250 A

Answer: Option B

Explanation: