Download PTU B-Tech ECE 2020 Dec 5th Sem 70545 Digital Communication Systems Question Paper

Download PTU (I.K.Gujral Punjab Technical University (IKGPTU)) B-Tech (Bachelor of Technology) (ECE)-Electronics And Communications Engineering 2020 December 5th Sem 70545 Digital Communication Systems Previous Question Paper

Roll No.
Total No. of Pages : 02
Total No. of Questions : 18
B.Tech. (ECE) (2012 to 2017) (Sem. ?5)
DIGITAL COMMUNICATION SYSTEMS
Subject Code : BTEC-501
M.Code : 70545
Time : 3 Hrs. Max. Marks : 60
INST RUCT IONS T O CANDIDAT ES :
1 .
SECT ION-A is COMPULSORY cons is ting of TEN questions carrying TWO marks
each.
2 .
SECT ION-B c ontains F IVE questions c arrying FIVE marks eac h and s tud ents
have to atte mpt ANY FOUR questio ns.
3 .
SECT ION-C contains THREE questions carrying T EN marks e ach and s tudents
have to atte mpt ANY TWO questions .
SECTION-A
Write briefly :
Q1. List advantages of digital communication system.
Q2. What is Aperture effect?
Q3. Write the basic difference between Bandpass transmission and Passband transmission.
Q4. Why do we use the Line coding formats?
Q5. How Slope over load distortion and Granular noise are avoided in ADM?
Q6. Draw the power spectrum of QPSK, MSK and BFSK each on same scale.
Q7. What do you mean by Non-linear quantization?
Q8. What is the relation between BER and SYMBOL error rate?
Q9. What do you mean by imperfect bit synchronization?
Q10. What is CDMA?
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SECTION-B
Q11. Why MSK is called shaped QPSK? For MSK, explain its expression and wave forms for
the signal 11000111.
Q12. What are the draw backs of DM? How are these overcome by ADM?
Q13. Write a note on probability of error for PSK and Draw wave forms of PSK for the bit
stream 101110001111.
Q14. Explain coherent and non-coherent ASK detector in detail.
Q15. The
probabilities
of
the
five
possible
outcomes
of
an
experiment
are
1
1
1
1
1
p
, 2
p
, 3
p , 4
p 5
p
. Find the entropy and information rate if there are
2
4
8
16
16 outcomes per second.
SECTION-C
Q16. Apply the Shannon-Fano algorithm to the source with M = 8 emitting messages
[X]= [A, B, C, D, E, F, G, H] having probabilities [P]= [1/2, 3/20, 3/20, 2/25, 2/25, 1/50,
1/100, 1/100]
Q17. Give comparison of DPCM and DM with standard PCM.
Q18. Write note on any two of following :
a) QPSK Receiver
b) FDMA and TDMA
c) Lampel-Ziv source coding algorithm with example
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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