CSIT 1st Semester
Digital Logics Board Question Paper 2081 Old Course

CSC 116-2081 ✡
Tribhuvan University
Institute of Science and Technology
2081
✡
Bachelor Level/First Year/First Semester/Science
Computer Science Information Technology (CSC 116)
(Digital Logics)
(Old Course)
Full Marks:60 Pass Marks:24 Time:3 hours

Candidates are required to give their answers in their own words as for as practicable.
The figures in the margin indicate full marks

Section A
Long Answer Questions
Attempt any Two question.
[2x10=20]
1.

Implement the following function F= Σ(0,1,3,5,7) using
a) Decoder
b) Multiplexer
c) PLA

2.

Design clocked sequential circuit of the following state diagram by using RS flip-flop.

3.

Implement full adder using Decoder and an OR gate. Explain its working mechanism.
clocked sequential circuit image

Section B

Attempt any Eight questions

[8x5=40]
4.

Represent decimal number 8620 in
a) BCD
b) Excess-3 code
c) 2421 code
d) Binary number

5.

Express the Boolean function F = xy+x'z in product of maxterm form.

6.

Reduce the following function using k-map.
F=A'D + BD + B'C + AB'D

7.

Design a combinational circuit that adds one to a 4-bit binary number, A₃A₂A₁A₀. For example, if the input of the circuit is A₃A₂A₁A₀ = 1101, the output is 1110. The circuit can be designed using four half-adders.

8.

Draw a logic diagram of a 2-to-4-line decoder with only NOR gates. Include an enable input.

9.

Design the odd parity generator circuit.

10.

Draw parallel-in parallel-out shift registers. Explain them.

11.

Design a 4-bit binary synchronous counter with D flip-flops.

12.

Write short notes on (Any two)
a) Reflected code
b) CMOS
c) Don't care