Electronics and Communication Engineering - Digital Electronics

21. 

The complement of exclusive OR function is

A. AB + A B
B. AB + A B
C. A B + A
D. AB + A B

Answer: Option B

Explanation:

Complement of XOR is X NOR.


22. 

Decimal -90 equals __________ in 8 bit 2s complement

A. 1000 1000
B. 1010 0110
C. 1100 1100
D. 0101 0101

Answer: Option B

Explanation:

+90 in binary is 01011010. Its 2's complement is 10100110.


23. 

23.610 = __________ 2

A. 11111.1001
B. 10111.1001
C. 00111.101
D. 10111.1

Answer: Option B

Explanation:

23= 10111 and 0.6 =10011 Hence 10111 . 10011 .


24. 

In a shift left register, shifting a bit by one bit means

A. division by 2
B. multiplication by 2
C. subtraction of 2
D. None of the above

Answer: Option B

Explanation:

In binary shift one bit left means multiplication by 2.


25. 

If A = B = 1, the outputs P and Q in the given figure are

A. P = Q = 0
B. P = 0, Q = 1
C. P = 1, Q = 0
D. P = Q = 1

Answer: Option B

Explanation:

It is a half adder 1 + 1 = 10. Therefore SUM = P = 0 and Carry = Q = 1.