Electronics and Communication Engineering - Digital Electronics

16. 

Two 2's complement number having sign bits X and Y are added and the sign bit of the result is Z. then, the occurrence of overflow is indicated by the Boolean function.

A. XYZ
B. X Y Z
C. X YZ + XY Z
D. XY + YZ + ZX

Answer: Option D

Explanation:

carry of a one bit full order is given by expression XY + YZ + ZX.


17. 

If A = 0101, then A' is

A. 1010
B. 1011
C. 1001
D. 0110

Answer: Option B

Explanation:

A' = 1010 + 1 = 1011.


18. 

11011 in gray code = __________ .

A. 100102
B. 111112
C. 111002
D. 100012

Answer: Option A

Explanation:

Change to decimal and then to binary.


19. 

In the circuit of the given figure, Y =

A. 0
B. 1
C. X
D. X

Answer: Option A

Explanation:

XX = 0.


20. 

A . 0 =

A. 1
B. A
C. 0
D. A or 1

Answer: Option C

Explanation:

1.0 = 0 and 0.0 = 0.