CSIT 1st Semester
Digital Logics Board Question Paper 2077

CSC 116-2077 ✡
Tribhuvan University
Institute of Science and Technology
2077
✡
Bachelor Level/First Year/First Semester/Science
Computer Science Information Technology (CSC 116)
(Digital Logics)
(New 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.

Design a combinatorial circuit that generates 9's complement of a BCD number.

2.

Implement the following functions using PLA
w (A, B, C, D) = ∑(3,12,13)
x (A, B, C, D)= ∑ (7,8,9,10,11,12,13,14,15)
y (A, B, C, D) = ∑ (0,2,3,4,5,6,7,8,10,11,15)
z (A, B, C, D) = ∑ (1,2,8,12,13)

3.

Design sequential circuit specified by the following state diagram using T flip-flops.
State diagram showing states 00, 01, 10, 11 with transitions labeled 0 and 1

Section B

Attempt any Eight questions

[8x5=40]
4.

List two major characteristics of digital computer. Represent -6 (negative six) using 8 bits in signed magnitude, signed-1's-complement and signed-2's-complement respectively. Represent decimal number 4673 in a) octal, and b) BCD.

5.

Where is CMOS suitable to use? Define Power dissipation. Show that the positive logic NAND gate is a negative logic NOR gate and vice versa.

6.

Design a full subtractor circuit with three inputs x, y, Bin and two outputs Diff and Bout. The circuit subtracts x-y-Bin where Bin is the input borrow, Bout is the output borrow, and Diff is the difference.

7.

Design 4-bit even parity generator.

8.

What is the difference between a serial and parallel transfer? Explain how to convert serial data to parallel and parallel data to serial. What type of register is needed?

9.

Explain negative-edge triggered D flip flop with necessary logic diagram and truth table.

10.

Illustrate the use of Binary ripple counter and BCD ripple counter.

11.

How binary addition is done? Show binary addition of (11001) with (11011).

12.

Write Short notes on (Any two)
a) RTL
b) State Reduction
c) POS