Question Paper: Digital Electronics & Logic Design Question Paper - December 2013 - Information Technology (Semester 3) - Savitribai Phule Pune University (SPPU)
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## Digital Electronics & Logic Design - December 2013

### SPPU Information Technology (Semester 3)

Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

### Solve any one question from Q1 and Q2

1 (a) Perform the following operations using 2's complement method.
i) -(48)10-(23)10
ii) -(48)10(-23)10
6 marks

1 (b) Compare totem pole and open collector output configurations in TTL. 6 marks

2 (a) Draw and explain 2 inputs TTL NAND gate with Totem Pole Output. 6 marks

2 (b) Design Full adder using suitable Decoder. 6 marks

### Solve any one question from Q3 and Q4

3 (a) What is Race around condition? How it can be avoided? Convert D Flip-Flop to T Flip-Flop. 6 marks

3 (b) Explain with a neat diagram working of 3 bit bidirectional shift register. 6 marks

4 (a) Explain the difference between Combinational and Sequential Circuit. Design S-R Flip-Flop using J-K Flip-Flop. 6 marks

4 (b) Design a sequence detector to detect the sequence ------- 110 ------- using J-K Flip-Flop. 6 marks

### Solve any one question from Q5 and Q6

5 (a) Explain difference between PAL & PLA. 6 marks

5 (b) Design a 4 bit BCD to Excess-3 code converter using PLA. 6 marks

6 (a) Explain difference between FPGA & CPLD. 6 marks

6 (b) Design the following function using PLA.
F1=∑m(1, 2, 4, 6)   F2=∑m(0, 1, 6, 7)   F3=∑m(2, 6)
6 marks

### Solve any one question from Q7 and Q8

7 (a) Explain entity and architecture in VHDL with syntax and example. 6 marks

7 (b) Explain Process statement in behaviour model of VHDL with respect to syntax, sensitivity list, declarative part and statement part. 6 marks

8 (a) Explain the difference between VHDL Modelling styles-Data Flow, Behavioural and Structural 6 marks

8 (b) Explain data objects in VHDL - signals, variables and Constants. 6 marks