 MORE IN Digital Circuit & System
RGPV Computer Science (Semester 3)
Digital Circuit & System
December 2015
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

1(a) What are universal gates? Why are they called so?
2 M
1(b) Add and subtract octal numbers 369 and 715
2 M
1(c) Design a BCD to Excess-3 code converter.
3 M
Solve any one question from Q.1(d) & Q.1(e)
1(d) Minimize the given Boolean function using K-map and implement the simplified function using only NAND gates.
F(A,B,C,D)= Σm(0,1,2,9,11,15)+d(8,10,14)
7 M
1(e) Minimize the given Boolean function using Quine-McCluskey method
F(a,B,C,D)= Σm(0,2,3,6,7,8,9,10)
7 M

2(a) Draw the truth table and logic diagram of full adder.
2 M
2(b) Draw the logic diagram of BCD adder and explain its working.
2 M
2(c) Draw the logic diagram of Ex-NOR gate using only NOR gates.
3 M
Solve any one question from Q.2(d) & Q.2(e)
2(d) Design a full subtractor circuit using decoder and OR gates.
7 M
2(e) Draw the logic of Ex-NOR gate using only NOR
7 M

3(a) Explain the terms-monostable,bistable and bistable and astable multivibrator.
2 M
3(b) Write characteristic of digital logic families.
2 M
3(c) Draw the circuit diagram of 2 input NAND gate (CMOS) and input NOR gate (TTL) and explain their working.
3 M
Solve any one question from Q.3(d) & Q.3(e)
3(d) Draw the circuit diagram of Schmitt trigger and explain it working.
7 M
3(e) Compare the following digital logic families RTL, DTL, TTL, ECL and CMOS.
7 M

4(a) Draw the logic diagram of priority encoder and explain its working
2 M
4(b) How a multiplexer can be used as a ROM?
2 M
4(c) Design a 4-bit synchronous up counter using J-K flip-flops.
3 M
Solve any one question from Q.4(d) & Q.4(e)
4(d) Implement the following Boolean function using 4:1 multiplexer using 4:1 multiplexer using A and B variables to the selection lines, F(A,B,C)= Σm(1,4,5,7)
7 M
4(e) What is RAM? Distinguish between SRAM and DRAM. What is PLA?
7 M

5(a) What is need of among to digital conversion?
2 M
5(b) Draw the circuit diagram of sample and hold circuit and explain it working.
2 M
5(c) Write short note on V-F converters.
3 M
Solve any one question from Q.5(d) & Q.5(e)
5(d) Enlist the various types of Analog to Digital (A/D) converter and explain any one if them with neat sketch.
7 M
5(e) Explain the operation of R-2R ladder type Digital to analog(D/A) converter with a neat sketch.
7 M

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