Electronics and Communication Engineering - Exam Questions Papers

46. 

For a lossless transmission line, the propagation constant is given as γ = __________ .

A. jω LC
B.
C. jω
D. jω

Answer: Option A

Explanation:

For lossless line, a = 0, R = 0 and G = 0


47. 

Consider the pulse shape s(t) as shown. The impulse response h(t) of the filter matched to this pulse is

A.
B.
C.
D.

Answer: Option C

Explanation:

h(t) = s(T - t).


48. 

If each stage has a gain of 10 dB and noise figure of 10 dB, then the overall noise figure of a two stage cascade amplifier will be

A. 10
B. 1.09
C. 1.0
D. 10.9

Answer: Option D

Explanation:

Overall noise figure F of the system is

F = F1 +

F1 = F2 = 10 dB = 10 in absolute units

g = 10 dB = 10 in absolute units

F = 10 + = 10.9 .


49. 

A rectangular waveguide of internal dimensions (a = 4 cm and b = 3) is to be operated in TE11 mode. The minimum operating frequency is

A. 6.25 GHz
B. 6.0 GHz
C. 5.0 GHz
D. 3.75 GHz

Answer: Option A

Explanation:

.


50. 

Using 4-bit numbers (n = 4) if k = 00112, how is k expressed in 2's complement?

A. 10112
B. 11012
C. 11002
D. 01012

Answer: Option B

Explanation:

In 2's complement k + 11012 = 2n = 16

So -k is represented by 11012 .


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