Communication Engineering (BEC401) - AKTU Question Paper 2025-26
B.Tech · Semester 4 · Free PDF Download
This is the official AKTU Communication Engineering Previous Year Question Paper for B.Tech Semester 4, academic session 2025-26. Published by Dr. A.P.J. Abdul Kalam Technical University (AKTU/UPTU), Lucknow. Free PDF download — no login required.
Course:B.Tech
Semester:Semester 4
Session:2025-26
University:AKTU / UPTU
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Questions Asked in 2025-26
Communication Engineering (BEC401) — extracted question text · 70 marks · 3 Hours
Section AAttempt all questions in brief. 02 x 7 = 14
- aState the need of modulation in communication system
- bCalculate the transmission efficiency of an AM signal with 100% modulation
- cState Carson’s rule for the bandwidth of an FM signal
- dDefine white noise and its power spectral density
- eWhat do you mean by time division multiplexing?
- fExplain the term granular noise in delta modulation
- gBriefly explain the concept of quadrature amplitude modulation
Section BAttempt any three of the following: 07 x 3 = 21
- aWhat do you mean by amplitude modulation (AM)? Derive the mathematical expression AM-DSB/FC. Also provide the graphical representation for modulation index less than one
- bExplain the Armstrong method of FM generation with a detailed block diagram and discuss the spectral characteristics of FM signals using Bessel functions
- cExplain the concepts of pre-emphasis and de-emphasis in FM and derive how they improve SNR
- dExplain the concept of companding in PCM systems and its importance
- eDraw and explain the block diagram for a binary frequency shift keying transmitter and receiver
Section CAttempt any one part of the following: 07 x 1 = 07
- aThe antenna current of an AM broadcast transmitter, modulated to a depth of 30% by an audio sine wave is 10A. It increases to 12A as a result of sinusoidal modulation by another audio sine wave. What is the modulation index due to second wave?
- bDraw the block diagram of a complete communication system and explain the function of each block. 1 K2 (SEM. IV) THEORY EXAMINATION 2025-26 COMMUNICATION ENGINEERING
- aDemonstrate the generation of FM with the help of PM and vice-versa
- bExplain the demodulation of an FM wave using a phase locked loop with a functional block diagram
- aState the various types of noises encountered in a communication system
- bDerive the expression for the signal to noise ratio and figure of merit for a double side band suppressed carrier system
- aDiscuss the process of quantization in PCM. Prove that for a PCM signal, the signal to quantization noise ratio in dB is 1.8 + 6n approximately, where n is the number of bits per sample
- bExplain Delta Modulation. Discuss the causes of slope overload distortion and how to minimize it. Derive mathematical expression of Smin
- aExplain amplitude shift keying using waveforms. Draw the block diagram for its generation and coherent detection
- bDescribe the minimum shift keying scheme. Prove that the phase of a minimum shift keying signal remains continuous at bit transitions
Question text is extracted from the official AKTU question paper PDF above. Check the original PDF for equations, diagrams and complete wording. Extracted: 2026-08-23.
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