Electronics and Communication Engineering - Exam Questions Papers

46. 

A 16 bit type ADC uses 1 MHz clock its maximum conversion time is __________ .

A. 16 μs
B. 15 ms
C. 6.5 ms
D. 66 ms

Answer: Option C

Explanation:

Conversion time =

⇒ 6.5 m sec.


47. 

A 300 MHz plane EM wave is propagating in free space. The wave is incident normally on an infinite copper slap. The antenuation constant for the wave is (σcopper = 5.8 x 107 mho/ m)

A. 262 x 103
B. 254 x 103
C. 352 x 103
D. 354 x 103

Answer: Option A

Explanation:

Attenuation constant : .


48. 

Transmitted voltage level is:

A. 11
B. 7.8
C. 7.348 V
D. none of these

Answer: Option C

Explanation:

= 61 + 0.5 = 61.5 = 7.348 V.


49. 

Which of the following is neither power nor energy signal?

A. sin 2t + cos 3t
B.
C. ramp
D. none of these

Answer: Option C

Explanation:

(A) is periodic thus power signal.

(B) is non periodic but finite thus energy signal.

(C) is non periodic but energy contain is infinite.

Thus it is neither power nor energy signal.


50. 

A periodic voltage has following values for equal time intervals changing suddenly from one value to next : 0, 5, 10, 20, 50, 60, 50, 20, 10, 5, 0, - 5, - 10 etc.
What would be the RMS value of a sine wave having the same peak value as that of the above mentioned periodic wave?

A. 42.2 V
B. 19.098 V
C. 38.2 V
D. none of these

Answer: Option A

Explanation:

R.M.S. value of a sine wave of the square peak == 42.2 V.


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