Computer Science and Information Technology - Digital Logic Design
Exam Duration: 45 Mins Total Questions : 30
With 2's complement representation, the range of values that can be represented on the date bus of 8-bit microprocessor is given by
- (a)
-128 to +127
- (b)
-127 to +128
- (c)
-127 to +127
- (d)
-256 to +256
An equivalent 2's complement representation of 2's complement of number 1101 is
- (a)
110100
- (b)
001101
- (c)
110111
- (d)
111101
The binary representation of number (10)4 is
- (a)
(1101010010000)2
- (b)
(1111000011010)2
- (c)
(101010011000)2
- (d)
(10111111111)2
BCD code of 45 is
- (a)
0111 0101
- (b)
0100 0101
- (c)
0110 0101
- (d)
1000 1000
Excess-3 code for (45)10 is
- (a)
0111 1001
- (b)
0111 1010
- (c)
0111 1000
- (d)
1010 1010
Excess -3 code for (13)10 is
- (a)
0100 0110
- (b)
0110 0110
- (c)
1001 1001
- (d)
0001 0011
What will be the complement of function x'yz' + x'y'z in product of sum form?
- (a)
(\(x+y+z\left( \bar { x } +y+z \right) \)
- (b)
\(\left( x+y+\bar { z } \right) \left( \bar { x } +y+\bar { z } \right) \)
- (c)
\(\left( x+\bar { y } +z \right) \left( x+y+\bar { z } \right) \)
- (d)
\(\left( x+\bar { y } +z \right) \left( \bar { x } +\bar { y } +\bar { z } \right) \)
What will be the reduced function value for function (CD' + A)' + A +CD +AB?
- (a)
AB + C
- (b)
CD + A
- (c)
CD' + A
- (d)
A + BD
The expression \(y=A+\bar { A } B\) is equivalent to
- (a)
y = AB
- (b)
\(y=\bar { A } +B\)
- (c)
y = A + B
- (d)
\(y=\bar { A } B\)
The number of half adder and full adder required to add m-bit data is
- (a)
\(\frac { m }{ 2 } \)half adder,\(\frac { m }{ 2 } \) full adder.
- (b)
1 half adder, m-1 full adder
- (c)
16 half adder, 0 full adder
- (d)
4 half adder, 12 full adder
The minimum number of 2 to 1(2:1) multiplexers required to realize a 4 to 1 multiplexer is
- (a)
4
- (b)
3
- (c)
2
- (d)
1
When an odd number is converted into binary number the LSB is
- (a)
0
- (b)
1
- (c)
0 or 1
- (d)
None of these
BCD addition of A(0101) and B(0110) gives
- (a)
1001
- (b)
1011
- (c)
1000
- (d)
None of these
An n-bit gray code can be obtained by rejecting an .............. bit code.
- (a)
n
- (b)
n + 1
- (c)
n -1
- (d)
None of these
Which of the following statements is true?
S1: The necessary condition for a weighted code to be self complementing is that the sum of weight must be 9.
S2: A cyclic code is that in which all successive code words differ in only one digit
- (a)
S1 is true
- (b)
S1, S2 are true
- (c)
S2 is true
- (d)
None of these
The equivalent in decimal for the excess-3 code 843 is
- (a)
840
- (b)
510
- (c)
846
- (d)
None of these
XOR is
- (a)
odd function
- (b)
even function
- (c)
Both a and b
- (d)
None of these
The Boolean expression AB + AB' + A'C +AC is independent of
- (a)
A
- (b)
B
- (c)
C
- (d)
None of these
The total number of Boolean function which can be realized with 4 variables is
- (a)
4
- (b)
256
- (c)
16
- (d)
65536
Demux can be used to realize
- (a)
counter
- (b)
shift register
- (c)
combinational circuit
- (d)
display system
The maximum number of outputs for a decoder with 6-bit data word would be
- (a)
64
- (b)
6
- (c)
24
- (d)
256
The m-bit adder contains........full-adder.
- (a)
m
- (b)
m+1
- (c)
m/2
- (d)
m-1
Match the following:
| Logic | Function | ||
| (a) | \(\bar { X } +\bar { Y } \) | (p) | Sum |
| (b) | XY | (q) | NAND |
| (c) | \(\bar { X } \bar { Y } \) | (r) | Carry |
| (s) | NOR | ||
- (a)
a-q, b-r, c-s
- (b)
a-q, b-s, c-r
- (c)
a-p, b-q, c-r
- (d)
a-q, b-s, c-r
If a computer will n-bit words size used 2's complement representation for numbers, what is the range of integers may be represented?
- (a)
-2n to 2n
- (b)
-2n-1 to 2n-1
- (c)
-2n-1 to 2n
- (d)
-2n to 2n-1
Convert (14.34)10 into binary.
- (a)
1011.1101
- (b)
1110.01010
- (c)
1110.1001
- (d)
1011.01001
A logical function of three variables is given as
\(f\left( A,B,C \right) =Y=\left( \bar { A } +B+C \right) \left( A+C \right) \left( \bar { A } +\bar { B } \right) \)
The canonical POS form is
- (a)
\(\pi \left( 1,3,9,1 \right) \)
- (b)
\(\pi \left( 2,3,5,8 \right) \)
- (c)
\(\pi \left( 0,2,6,7 \right) \)
- (d)
\(\pi \left( 1,2,8,10 \right) \)
Match the following:
| (a) Encoder | 1. One of many |
| (b) Demux | 2. Some of many |
| (c) Decoder | 3. Many to some |
- (a)
a-1, b-2, c-3
- (b)
a-3, b-1, c-2
- (c)
a-1, b-2, c-3
- (d)
None of these
The 10's complement of a number is (47480)10
Find the number in decimal equivalent
- (a)
52520
- (b)
34380
- (c)
63620
- (d)
37480
The 10's complement of a number is (47480)10
The octal equivalent of the answer of above question is
- (a)
(146450)8
- (b)
(63620)8
- (c)
(52520)8
- (d)
None of these
The number of 2x1 muxer needed to construct 8x1 mux is
- (a)
7
- (b)
3
- (c)
8
- (d)
none of these
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