EX-403 Digital Electronics and Logic Design (DELD) - Jun 2022 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. 7 Marks
   aExplain in detail about Parity generator and checkers.
   How to answer

   • Definition of parity bit, even vs odd parity
   • Parity generator circuit operation and truth table
   • Parity checker circuit operation and truth table
   • Error detection example
2. 7 Marks
   bWhy NAND and NOR gates are called universal gates? Realize AND, OR with the help of NAND and NOR gates.
   How to answer

   • Definition of universal gate property
   • Reason NAND/NOR can realize any Boolean function
   • AND, OR realization using NAND with diagrams
   • AND, OR realization using NOR with diagrams
3. 7 Marks
   aWhat is De-Multiplexer? Design the given expression using $4\times1$ multiplexer $F(A,B) = \bar{A}+\bar{B}$
   How to answer

   • Definition of De-Multiplexer and block diagram
   • Truth table of 4x1 multiplexer
   • Simplification of $F(A,B)$
   • Implementation wiring using 4x1 MUX
4. 7 Marks
   bWhat is half adder? Write its truth table and design the logic circuit.
   How to answer

   • Definition of half adder with block diagram
   • Truth table for inputs A,B and outputs Sum, Carry
   • Boolean expressions Sum = A xor B, Carry = A.B
   • Logic circuit using XOR and AND gates
5. 7 Marks
   aWhat do you mean by flip-flop? Explain with the help of diagrams and tables?
   How to answer

   • Definition of flip-flop as 1-bit bistable memory
   • Basic block diagram and types
   • Example SR/JK truth tables and waveforms
   • Difference from latch/level vs edge triggering
6. 7 Marks
   bWhat are Latches? Write applications of flip-flop.
   How to answer

   • Definition of latch vs flip-flop
   • SR/D latch operation
   • Applications: registers, counters, memory, debouncing
   • Summary of uses
7. 7 Marks
   aWhat is Asynchronous and Synchronous counter? Give some applications of counter.
   How to answer

   • Definition of synchronous vs asynchronous counter
   • Clocking difference and timing diagram
   • Comparison of speed/complexity
   • Applications: frequency division, timers, DAC control
8. 7 Marks
   bWrite about Ring counter and universal shift registers.
   How to answer

   • Ring counter circuit and operation with states
   • Universal shift register block and modes
   • Shift left/right/parallel operation
   • Applications
9. 7 Marks
   aWhat is ROM and its types?
   How to answer

   • Definition of ROM as non-volatile memory
   • Block structure and operation
   • Types: PROM, EPROM, EEPROM, Flash
   • Comparison of programmability
10. 7 Marks
    bExplain about combinational PLD's.
    How to answer

    • Definition of PLD and combinational PLD
    • PROM/PLA/PAL structure
    • AND-OR plane concept
    • Example implementation
11. 7 Marks
    aDefine Encoder and design 2-bit magnitude comparator.
    How to answer

    • Definition of encoder with truth table
    • 2-bit comparator inputs A1A0, B1B0
    • Logic expressions for A>B, A<B, A=B
    • Logic circuit implementation
12. 7 Marks
    bConvert the following (i) $(1001.0101)_{2}$ to Decimal (ii) $(137.21)_{8}$ to decimal.
    How to answer

    • Positional weight formula for binary and octal
    • Convert integer and fractional parts separately
    • Calculation for $(1001.0101)_2$
    • Calculation for $(137.21)_8$
13. 7 Marks
    aConvert SR flip-flop to JK flip-flop
    How to answer

    • Excitation tables of SR and JK flip-flops
    • K-map simplification for S,R in terms of J,K,Qn
    • Expressions $S=J\bar{Q_n}$, $R=KQ_n$
    • Logic diagram of conversion
14. 7 Marks
    bExplain BCD counter with the help of diagram.
    How to answer

    • Definition of BCD/decade counter mod-10
    • Four flip-flops with reset on 1010
    • Logic/circuit diagram using JK flip-flops and NAND
    • Counting sequence table 0000 to 1001
15. 14 Marks
    Write short notes on the following :-

    1. a)De-Morgan's theorem
    2. b)RAM
    3. c)PLA and PAL
    How to answer

    • De-Morgan's theorem statements and proof with truth table
    • RAM definition, types SRAM/DRAM and block
    • PLA vs PAL structure and differences
    • Diagrams for each