JNTU
JNTU B.Tech II DIGITAL LOGIC AND PULSE CIRCUITS Previous Question Paper (July/August - 2021 - R16)
Answer any Five Questions
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Main
Encode the decimal numbers into:
i) (56)10 = ( ) Gray code
ii) (20.305)10 = ( ) Excess-3 code
iii) (32.89)10 = ( ) BCD code
Answer
i) To convert (56)10 to Gray code: First, convert to binary. (56)10 = (111000)2. Perform the conversion (Gi = Bi ⊕ Bi+1): 1, 1⊕1=0, 1⊕1=0, 0⊕1=1, 0⊕0=0, 0⊕0=0. Thus, (56)10 = (110100)Gray.
ii) To convert (20.305)10 to Excess-3: Add 3 to each decimal digit. 2+3=5, 0+3=3, 3+3=6, 0+3=3, 5+3=8. Converting each to 4-bit BCD: 5=0101, 3=0011, 6=0110, 3=0011, 8=1000. Thus, (20.305)10 = (01010011.011000111000)Excess-3.
iii) To convert (32.89)10 to BCD: Convert each digit to 4-bit binary. 3=0011, 2=0010, 8=1000, 9=1001. Thus, (32.89)10 = (00110010.10001001)BCD.
Encode the message bits (1110)2 into 7-bit even parity hamming code.
Answer
For a 4-bit message (d1d2d3d4 = 1110), the 7-bit Hamming code requires 3 parity bits (P1, P2, P4). The positions are: P1, P2, d1, P4, d2, d3, d4. Substituting bits: P1, P2, 1, P4, 1, 1, 0.
Calculate parity bits for even parity:
- P1 checks positions 1, 3, 5, 7: P1 ⊕ 1 ⊕ 1 ⊕ 0 = 0, so P1 = 0.
- P2 checks positions 2, 3, 6, 7: P2 ⊕ 1 ⊕ 1 ⊕ 0 = 0, so P2 = 0.
- P4 checks positions 4, 5, 6, 7: P4 ⊕ 1 ⊕ 1 ⊕ 0 = 0, so P4 = 0.
The resulting 7-bit even parity Hamming code is 0010110.
What is the use of complements? Give examples of 1′s complement and 2′s complement.
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Explain various number systems and Binary codes used in digital logic design with examples.
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Simplify the following function using K-map:
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Implement the following logic function using 16:1 Multiplexer and 8:1 Multiplexer.
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Using the QM method, obtain the simplified expression for:
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Give the limitations of K-mapping method.
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Draw the circuit diagram of a 4 bit UP/DOWN binary counter and explain its working.
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Explain the working of synchronous sequential circuits and asynchronous sequential circuits with examples and mention their applications.
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Obtain the characteristic equations of JK, SR, D and T flip-flops. Also explain excitation tables of all these flip-flops.
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Draw the basic circuit diagram of positive and negative peak clamper circuits and explain their operation.
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What is Ringing Circuit? Explain its operation along with circuit diagram.
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Explain the operation of Bistable Multivibrator circuit.
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Draw the circuit diagram of Transistor Miller Time Base generator and explain its operation.
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