Tribhuwan University

Institute of Science and Technology

2080

Bachelor Level / First Year / First Semester / Science

Bachelors in Information Technology (BIT103)

(Digital Logic)

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 Answers Questions

Attempt any TWO questions.
[2*10=20]
1.
Define BCD code. Design BCD to Excess-3 Code converter with truth table and logic diagram.[10]
2.
Define combinational logic circuit. Design a combinational circuit whose input is a four-bit number and output is the 1's complement of the input number.[10]
3.
Define parallel counter. Design MOD-12 synchronous up counter along with state diagram, timing sequence and timing diagram.[10]
Section B

Short Answers Questions

Attempt any Eight questions.
[8*5=40]
4.
Why NAND and NOR gates are called Universal logic gates? Realize NOR as Universal logic gates. [5]
5.
Simplify: F = X Y Z' + X Z' + X' Y + X'' Y Z' using K-Map in both SOP and POS. [5]
6.
Define PLDs. Implement the given functions with ROM. F1 = $(\Sigma(0,1,2)$, F2 = $\Sigma(0,2,3)$ [5]
7.
Describe the clocked master-slave J-K flip-flop with its operation table. [5]
8.
What is forbidden state in SR flip flop? Convert SR to JK flip flop. [5]
9.
Differentiate between ring counter and Johnson counter. [5]
10.
Explain the operation of 4-bit Parallel-In parallel-Out Shift register with data input 1010. [5]
11.
Write short notes on: (Any two) a.) ASCII Code b.)Logic micro operation c.) State table [5]
12.
Convert $(591.62)_{10}$ into hexadecimal and octal number system. [5]