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Special Examination
Aug. 2023
Max. Marks: 100
Class: T.E.
Course Code: ET/EX 301
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Duration: 3 Hrs
Semester: V
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communication
instruction:
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(1) All questions are compulsory
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TI0U! eTtieS of a^log/pUlse/ digital communication system
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methodsTndmP^6”1 P7jOrmanCe of various analog/pulsed/digital modulation
methods in time domain/ frequency domain/ signal space
with
behaViOr ofa various analog/pulse/digital modulation schemes
with and without noise
CSjCompare various modulation/demodulation techniques
Q No7~7
Q.l a
Q.l b
Max.
CO­
Marks BL
Derive frequency domain expression of double sideband full carrier
To2-3
wave with AM envelope. Sketch AM waveform and define modulation index
A sinusoidal carrier Vc =~1U * co,(2 , p, * 2000 * t) is
modulated by a sinusoidal voltage Vm = 5 * cos(2 * pz * 100 * D
upto modulation depth of 60 percent. Calculate the amplitude
and frequency of each side band and the total power for amplitude
modulated signal.Sketch frequency spectrum
10
3-3
OR
Q.2 a
Q.2 b
Q.2 c
Q.3a
W
Q3c
When the modulating frequency in an PM system is 500Hz and
modulating voltage is 2V. modulation index is 55. Calculate the
maximum deviation . What is the modulating index at modulating
voltage of 5V and modulating freq u e n cy 40011 z.
Compare Frequencv division 11111^iplexing and Time division multiplcxing
Describe pulse code modulation transmission and reception for telcphony application with appropriate block di a gra 111.
Describe SSB generation transmission with appropriate block diagrani.
Explain BPSK transmitter and receiver with a neat, bio ok diagram.
Analyze the following niodi.ilat.ions B-PSK and BFSK.
Sketch waveform of NHZ. PZ. Man( h(‘ster. AMI foi data 101010~ ‘
10
3-3
10
5-1
10
1-2
10
1-2
10
10
5-1
4-4
4-4
10
- rr -
^.4a
A binary data stream (Refer to the table at the end of paper for the
input sequence) is applied to a duobinary encoder. Consider the
initial value of encoder input as minus one (w.bfc-i) = -1).Sketch
figure of enocoder for both cases and state the decision rule at the
decoder in each case.
Compute output of duobinary encoder and decoder
10
4 4 •
Q4b
Describe working of QPSK transmitter and mention its advantages
and disadvantages
10
3-4