B.TechSemester 62023-24Digital CommunicationKEC601

Digital Communication (KEC601) - AKTU Question Paper 2023-24

B.Tech · Semester 6 · Free PDF Download

This is the official AKTU Digital Communication Previous Year Question Paper for B.Tech Semester 6, academic session 2023-24. Published by Dr. A.P.J. Abdul Kalam Technical University (AKTU/UPTU), Lucknow. Free PDF download — no login required.

Course:B.Tech

Semester:Semester 6

Session:2023-24

University:AKTU / UPTU

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Questions Asked in 2023-24

Digital Communication (KEC601) — complete question paper · 100 marks · 3 Hours

Section AAttempt all q u e s t i o n s i n b r i e f .

a
State properties of pdf. 02
b
Discuss about complete probability scheme. 02
c
Describe Eye diagram. 02
d
Illustrate roll-off factor in pulse shaping. 02
e
Discuss the disadvantages of c oherent demodulation schemes. 02
f
Discuss the disadvantages of non-coherent FSK. 02
g
Illustrate the term spread s pectrum and its advantages. 02
h
Compare ASK, FSK, and PSK based on the probability of error performance. 02 i. Discuss the reason of using the logarithmic function for the m easurement of information j. Appraise that the mutual informa tion is symmetric in nature. 0 2

Section BAttempt any three o f t h e f o l l o w i n g :

a
Demonstrate random process. Illustrate the characteristics o f the Strict sense stationary process
b
Discuss Duobinary signaling. Discuss the advantages of using it. 10
c
Describe ASK modulation and demodulation in detail. 10
d
Illustrate FHSS with FSK modul ation with the help of Transmitter and Receiver diagram. Discuss its disadvantages also
e
Analyze the relations between different entropies. Also disc uss physical interpretations of all entropies

Section CAttempt any one p a r t o f t h e f o l l o w i n g :

a
Consider the general Gaussian PDF: Determine the mean and variance
b
Discuss Wide sense stationary process. Determine whether the given random process is a wide sense stationary process or not? Xሺtሻ ൌ ACosሺωt ൅ Ωሻ Where, Ω is a uniformly distributed random variable between 0 to 2Π
a
Illustrate scrambling. Also describe the reason of using it. If the data stream is 101010100000111, Determine the scrambled output. Given F=D 3 (XOR)D 5
b
Derive expression for the PSD of Polar line codes. 10
a
Discuss DPSK modulation and demodulation in detail. 10
b
Discuss FSK modulation and demodulation in detail. 10
a
Analyze that the output signal of a matched filter is propor tional to a shifted version of the Autocorrelation function of the input signal to which the filter is matched
b
Derive an expression for the probability of error of PSK modulation. 10
a
A memoryless source emits si x messages with probability 0.3, 0.25, 0.15, 0.12, 0.1 and 0.08. Here, M=2
1
Find the binary Huffman code
2
Determine its average word length, efficiency and redundancy
b
Design (2,1,2) Convolutional encoder. 10

Question text is extracted from the official AKTU question paper PDF above. Hindi translations are omitted — every question is printed in English in the original paper. Last verified: 2026-08-23.