EC-303 Digital System Design - Jun 2024 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 3 Marks
   a$(2048.0625)_{10} = (\quad)_2$
   How to answer

   • Convert integer part by successive division by 2
   • Convert fractional part 0.0625 by successive multiplication by 2
   • Combine integer and fraction binary equivalents
2. 3 Marks
   b$(011.101101)_2 = (\quad)_8$
   How to answer

   • Group binary bits in threes from binary point
   • Replace each 3-bit group by octal digit
   • Combine integer and fractional octal result
3. 3 Marks
   c$(1923)_8 = (\quad)_2$
   How to answer

   • Replace each octal digit by 3-bit binary
   • Remove leading zeros if any
   • Write final binary number
4. 3 Marks
   d$(641A)_{16} = (\quad)_8$
   How to answer

   • Replace each hex digit by 4-bit binary
   • Regroup binary bits in threes for octal
   • Replace each group by octal digit
5. 2 Marks
   e$(572)_{10} = (\quad)_{gray}$
   How to answer

   • Convert decimal 572 to binary
   • Convert binary to Gray by Ex-OR of successive bits
   • Write final Gray code
6. 7 Marks
   aSimplify the following function: $Y = (A+B)(\bar{A}\bar{C}+C)\left(\overline{(\bar{B}+AC)}\right)$ $Y = \bar{A}C\overline{(\bar{A}BD)}+\bar{A}B\bar{C}\bar{D}+A\bar{B}C$
   How to answer

   • Apply De Morgan's theorem and Boolean identities
   • Simplify $(A+B)(\bar{A}\bar{C}+C)$ and $\overline{(\bar{B}+AC)}$ terms
   • Simplify $\bar{A}C\overline{(\bar{A}BD)}+\bar{A}B\bar{C}\bar{D}+A\bar{B}C$ to minimal sum-of-products
7. 7 Marks
   bSimplify the following function using k-map. $Y = ABCD + A\bar{B}C\bar{D} + A\bar{B}C + AB$ $Y = \Sigma_m(0,2,3,6,7) + \Sigma_d(8,10,11,16)$
   How to answer

   • Plot 4-variable K-map for given SOP and minterms with don't cares
   • Form maximal groups of 1s including don't cares
   • Write minimal SOP expression for Y
8. 14 Marks
   Minimize the following function using Quine McCluskey method. $f = \Sigma(1, 2, 3, 5, 6, 9, 10, 13, 15)$
   How to answer

   • Group minterms by number of 1s and combine to find prime implicants
   • Construct prime implicant chart
   • Select essential prime implicants for minimal cover
9. 7 Marks
   aDesign a full subtractor.
   How to answer

   • Define full subtractor inputs A, B, Bin and outputs Difference, Borrow
   • Derive truth table and K-map simplified expressions
   • Draw logic diagram using gates / half subtractors
10. 7 Marks
    bDesign a BCD adder.
    How to answer

    • Add two BCD digits using 4-bit binary adder
    • Detect correction condition when sum > 9 or carry generated
    • Add 0110 correction using second adder to get BCD result
11. 7 Marks
    aExplain the working of master slave flip-flop.
    How to answer

    • Describe master and slave SR/JK latches with clock and inverted clock
    • Explain master enabled on one level and slave on opposite level
    • Explain race-around avoidance and timing waveforms
12. 7 Marks
    bDesign a pulse train generator.
    How to answer

    • Define pulse train generator requirement and sequence
    • Select shift register / counter with feedback logic
    • Draw circuit and timing diagram of generated pulses
13. 14 Marks
    Design MOD-7 counter using JK flip-flop.
    How to answer

    • Determine 3 flip-flops for 7 states and state diagram
    • Derive excitation table for JK flip-flops and K-map simplification
    • Draw logic diagram with feedback and unused state handling
14. 7 Marks
    aExplain the following logic families TTL
    How to answer

    • Give basic principle and circuit of TTL family
    • Give basic principle and circuit of ECL family
    • Compare speed, power, noise margin and applications
15. 7 Marks
    bECL
    How to answer

    • Give basic principle and circuit of ECL family
    • Explain emitter-coupled operation and OR/NOR outputs
    • Mention speed, power dissipation and applications
16. 14 Marks
    Write short notes on any two of the following:

    1. a)Carry look ahead adder
    2. b)Shift register
    3. c)Pseudo Random Binary sequence generator
    How to answer

    • Explain principle, diagram and working of chosen topics
    • Mention key formulas / modes / advantages
    • Give applications of chosen topics