Published by: Dikshya
Published date: 13 Mar 2023
POKHARA UNIVERSITY – Digital System Fall 2017
Level: Bachelor Semester: Spring Year:2017
Program: BBA/BBA-BI/BCIS/BHCM/BBA-TT Full Marks: 100
Course: Digital System Pass Marks: 45
Time: 3 hrs
Section “A”
Very Short Answer Questions
Attempt all the questions. 10×2
1. Define the parity bit.
2. Define algorithm for state reduction method of a sequential circuit.
3. Draw the block diagram of a combinational and sequential circuit.
4. Can you realize a 2-input NOR using 2 input NAND gates only.
5. Define K-map.
6. What are the two main functions of the registers? Explain.
7. If there are 235 outputs in demultiplexer, find a number of selection lines
and input lines.
8. Define flip-flop.
9. Find the base x if (211) x = (152) 8 .
10. Represent (-39) 10 into sign-magnitude, 1’s complement and 2’s
complement form.
Section “B”
Descriptive Answer Questions
Attempt any six questions
11. Perform the following calculations
a) (110- 11011) 2 using 1’s and 2’s complement system.
b) (345-67) 10 using 9’s and 10’s complement system.
12. Define logic gates. Explain about 7 different types of logic gates along with Boolean expression, logic symbol, truth table.
13. Differentiate between combinational and sequential circuit. Also explain about characteristics and excitation table of the JK flip flop.
14. Define decoder. Construct a full adder using a 3 x 8 decoder and explain.
15. What is a multiplexer? Realize a full adder using MUX and explain.
16. What do you mean by ripple counter? Draw the circuit diagram of 4-bit ripple counter and explain its working principle along with the timing diagram.
17. Explain the importance of registers and explain briefly about the 4 bit 2 serial-in-parallel out shift registers with the help of a timing diagram.
Case Analysis
18. Design a BCD to seven- segment display circuit.
19. a) Define ALU. Explain about 4 bit ALU.
b) What do you mean by edge-triggered flip flop? Explain.