Digital Logic 2080

Section A

Long Answer 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 whose output is the 1's complement of the input number. [2+8]

3. Define parallel counter. Design MOD-12 synchronous up counter along with state diagram, timing sequence, and timing diagram. [2+8]

Section B

Short Answer Questions
Attempt any EIGHT questions. [8 × 5 = 40]

4. Convert (591.62)_10 into hexadecimal and octal number system. [2.5+2.5]

5. Why are NAND and NOR gates called Universal logic gates? Realize NOR as a Universal logic gate. [1+4]

6. Simplify: F = XYZ' + XZ' + X'Y + X''YZ' using K-Map in both SOP and POS. [2.5+2.5]

7. Define PLDs. Implement the given functions with ROM:
F1 = ∑(0,1,2)
F2 = ∑(0,2,3) [5]

8. Describe the clocked master-slave J-K flip-flop with its operation table. [5]

9. What is  forbidden state in SR flip-flop? Convert SR to JK flip-flop. [1+4]

10. Differentiate between ring counter and Johnson counter. [5]

11. Explain the operation of a 4-bit Parallel-In Parallel-Out Shift register with data input 1010. [5]

12. Write short notes on (Any two):

• a. ASCII Code
• b. Logic micro operation
• c. State table