Electrical Engineering 2023 Paper II 50 marks Solve

Q4

(a) Consider a systematic linear block code with binary elements whose parity check equations are p₁ = m₁ + m₂ + m₃ p₂ = m₂ + m₃ + m₄ p₃ = m₁ + m₃ + m₄ p₄ = m₁ + m₂ + m₄ where mᵢ are message digits and pᵢ are parity check digits. (i) Find the generator matrix and parity check matrix for the code. (ii) How many errors can this code detect? How many errors can be corrected? (iii) If 10100100 is the received code word, find the corresponding transmitted code word assuming that single-bit error has been made during transmission. 20 marks (b) A transmission line has the following parameters : A = D = 1∠5°, B = 88∠75° (i) Determine the sending-end voltage and the voltage regulation if the line supplies a load of 40 MW at 0·8 p.f. lagging with receiving-end voltage 132 kV. (ii) Find the power and power factor of the load if the voltages at the two ends are 132 kV and with a phase difference of 30°. 20 marks (c) Explain four instructions which are used to control interrupt structure of 8085 microprocessor. 10 marks

हिंदी में प्रश्न पढ़ें

(a) द्वि-आधारी घटकों के साथ एक क्रमबद्ध रैखिक खण्ड कूट पर विचार कीजिए, जिसके सामंजस्य (पैरिटी) जाँच समीकरण हैं p₁ = m₁ + m₂ + m₃ p₂ = m₂ + m₃ + m₄ p₃ = m₁ + m₃ + m₄ p₄ = m₁ + m₂ + m₄ जहाँ mᵢ संदेश अंक एवं pᵢ सामंजस्य जाँच अंक हैं। (i) इस कूट के लिए जनक मैट्रिक्स एवं सामंजस्य जाँच मैट्रिक्स ज्ञात कीजिए। (ii) यह कूट कितनी त्रुटियों का पता लगा सकता है? कितनी त्रुटियों को संशोधित किया जा सकता है? (iii) यदि 10100100 प्राप्त हुआ कूट-शब्द है, तो यह मानते हुए कि संचरण में एकल-बिट त्रुटि की गयी है, संगत संचारित कूट-शब्द ज्ञात कीजिए। 20 अंक (b) एक संचरण लाइन के प्राचल निम्नलिखित हैं : A = D = 1∠5°, B = 88∠75° (i) प्रेषण सिरे की वोल्टता एवं वोल्टता नियमन ज्ञात कीजिए, यदि लाइन अभिग्राही सिरे की 132 kV वोल्टता के साथ एक 40 MW भार को 0·8 पश्चता शक्ति गुणक पर प्रदाय करती है। (ii) भार की शक्ति एवं शक्ति गुणक ज्ञात कीजिए, यदि दोनों सिरों पर 132 kV की वोल्टता एवं 30° का कलांतर हो। 20 अंक (c) 8085 सूक्ष्म-संसाधित्र (माइक्रोप्रोसेसर) की क्रमभंजक (इंटरप्ट) संरचना को नियंत्रित करने वाले चार अनुदेशों की व्याख्या कीजिए। 10 अंक

Evaluate your answer to this question → See all 2023 Electrical Engineering questions

Directive word: Solve

This question asks you to solve. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

See our UPSC directive words guide for a full breakdown of how to respond to each command word.

How this answer will be evaluated

Approach

Solve this multi-part numerical and descriptive problem by allocating approximately 40% time to part (a) coding theory (20 marks), 40% to part (b) transmission line calculations (20 marks), and 20% to part (c) 8085 interrupt instructions (10 marks). Begin with systematic matrix construction for (a), proceed to ABCD parameter calculations for (b), and conclude with concise instruction descriptions for (c). Present all derivations stepwise with clear intermediate results.

Key points expected

  • For (a)(i): Construct 4×8 generator matrix G = [I₄|P] and 4×8 parity check matrix H = [Pᵀ|I₄] from given parity equations, verifying GHᵀ = 0
  • For (a)(ii): Determine minimum Hamming distance dₘᵢₙ = 3 from H matrix columns, hence error detection capability = 2 errors, correction capability = 1 error
  • For (a)(iii): Compute syndrome S = rHᵀ, identify error position from syndrome pattern, and correct received word 10100100 to transmitted codeword
  • For (b)(i): Apply ABCD parameters with Vᵣ = 132∠0° kV, Iᵣ = 40×10⁶/(√3×132×10³×0.8) ∠-36.87° A to find Vₛ = AVᵣ + BIᵣ and voltage regulation = (|Vᵣₙₗ| - |Vᵣբₗ|)/|Vᵣբₗ| × 100%
  • For (b)(ii): Use Vₛ = 132∠30° kV, Vᵣ = 132∠0° kV in transmission equation to solve for current and hence complex power S = 3VᵣIᵣ* and power factor
  • For (c): Explain EI (Enable Interrupts), DI (Disable Interrupts), SIM (Set Interrupt Mask), and RIM (Read Interrupt Mask) instructions with their specific roles in 8085 interrupt control structure

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Correctly identifies systematic code structure for (a), recognizes ABCD parameter physical significance for (b), and accurately describes all four 8085 interrupt control instructions with their flag/register interactions for (c)Basic understanding of linear block codes with minor errors in matrix identification; knows transmission line modeling but confuses parameter meanings; lists interrupt instructions with superficial descriptionsFundamental misunderstanding of generator/parity check matrix relationship; treats ABCD parameters as impedance/admittance; confuses 8085 interrupt instructions with 8086 or general 8259 operations
Numerical accuracy25%12.5Precise computation of syndrome and error correction in (a)(iii); correct polar/rectangular conversions in (b) with voltage regulation within 0.5% and power factor accurate to two decimal placesCorrect methodology but arithmetic errors in matrix multiplication or complex number operations; final answers within 10% of correct valueMajor calculation errors in syndrome computation; incorrect angle handling in ABCD equations; order-of-magnitude mistakes in power calculations
Diagram quality10%5Clear matrix layouts with proper dimension labels for (a); phasor diagram showing Vₛ, Vᵣ, Iᵣ relationship for (b); 8085 interrupt structure diagram showing RST 7.5-5.5, INTR, TRAP hierarchy for (c)Basic matrices without labels; simple line diagram for transmission; minimal or no diagrams for interrupt structureMissing or incorrect diagrams; confused matrix notation; no visual representation of phasor relationships
Step-by-step derivation25%12.5Explicit derivation of G from parity equations showing I₄ and P submatrices; systematic syndrome calculation with error pattern table; complete ABCD parameter derivation with intermediate complex arithmetic shown; instruction opcode and flag effects detailedShows key steps but skips intermediate matrix multiplications; presents final formulas without derivation; partial working for complex power calculationJumps to final answers without derivation; incorrect or missing steps in syndrome calculation; no working shown for transmission line equations
Practical interpretation15%7.5Relates (2,1) error detection/correction trade-off to ARQ systems in Indian satellite/terrestrial communication; interprets voltage regulation significance for grid stability in Indian power networks; connects 8085 interrupt control to real-time industrial process control applicationsGeneric statements about coding importance; basic mention of power quality; superficial link to microprocessor applicationsNo practical context provided; purely mathematical treatment without engineering significance; irrelevant examples from non-Indian contexts

Practice this exact question

Write your answer, then get a detailed evaluation from our AI trained on UPSC's answer-writing standards. Free first evaluation — no signup needed to start.

Evaluate my answer →

More from Electrical Engineering 2023 Paper II