Electronics and Communication Engineering - Exam Questions Papers

21. 

What are the minimum number of 2 to 1 multiplexers required to generate a 2 input AND gate a 2 input Ex-OR gate?

A. 1 and 2
B. 1 and 3
C. 1 and 1
D. 2 and 2

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

22. 

Transfer function of a certain system is:

The approximate 2% settling time for unit step input is

A. 2 sec
B. 4 sec
C. 6 sec
D. 8 sec

Answer: Option B

Explanation:

Pole '-120' will have no effect on settling time.


23. 

On which bands, do the optical fibers operate?

  1. Ultra violet band
  2. Ultra high frequency band
  3. Visible light band
  4. Infrared band
Select the correct answer from the codes given below:

A. 1 only
B. 1 and 2 only
C. 1, 2 and only
D. 1, 3 and 4

Answer: Option D

Explanation:

No answer description available for this question. Let us discuss.

24. 

A 3 stage Johnson counter shown in figure is clocked at a constant frequency of fc from the starting state of Q0 Q1 Q2 = 101. The frequency of output Q0 Q1 Q2 will be

A. fc/2
B. fc/3
C. fc/6
D. fc/8

Answer: Option C

Explanation:

No answer description available for this question. Let us discuss.

25. 

Which of the following conditions should be satisfied to call an astable multivibrator circuit using discrete components as a digital circuit?

  1. A flip-flop is always a digital circuit.
  2. Only when we assign 1 and 0 to the high and low levels of the output, a flip-flop is called a digital circuit.
  3. Only if the power, supply voltage is maintained at + 5 V or - 5 V, it is called a digital circuit.
  4. Only if it is in IC form, following the technology of IC manufacture, it is called a digital circuit.
Select the correct answer from the codes given below:

A. 1 only
B. 2 and 3
C. 2 only
D. 3 and 4

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.