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Solution to Previous Year Exam Questions pyq for Data Communications - DC of 2017 - KTU by Remya Sasi

  • Data Communications - DC
  • 2017
  • PYQ Solution
  • APJ Abdul Kalam Technological University - KTU
  • Computer Science Engineering
  • B.Tech
  • 36 Offline Downloads
  • Uploaded 1 year ago
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APJ ABDULKALAM TECHNOLOGICAL UNIVERSITY FIFTH SEMESTER B.TECH EXAMINATION, DECEMBER 2017 DEPARTMENT: COMPUTER SCIENCE AND ENGINEERING SUBJECT:CS307 DATA COMMUNICATIN TIME: 3HOURS MAX MARKS:100 PART A Answer All questions 1. Explain time domain and frequency domain 2. A periodic signal is decomposed into five sine waves with frequencies 100, 200, 300, 400, 800 Hz what is the bandwidth? 3. A signal travels from point A to point B. At point A, the signal power is100 W. At point B the power is 80 W. What is the attenuation in decibel? 4. Explain satellite communication 4*3= 12 marks PART B Answer Any Two Full questions 5. a) Explain the different transmission impairments that affect data communications (7 Marks) b) A file contain 3 million bytes. How long does it take to download the file using 56 Kbps Channel.? 1 Mbps channel (2 Marks) 6. a)What do you meant by Nyquist bandwidth and Shannon capacity formula (3 Marks) b) For a parabolic reflective antenna with a diameter of 2 m operating at 12Ghz. What is the effective area and antenna gain? (2 Marks) c) Explain wireless propagation in detail (4 Marks) 7. Explain the structure , applications, transmission characteristics of guided media(9 Marks) (18 Marks) PART C Answer All questions 8. Consider the following lists stream: 0100010 . Encode the above bit stream using. a) NRZ – L b) NRZ – I 9. write short notes on CDMA Studoob.in - Where Learning is Entertainment

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10 five channels each with a 100 Khz bandwidth are to be multiplexed together. What is the minimum bandwidth of the link if there is a need for a guard band of 10khz between the channel to prevent interference? 11. Explain the advantages and disadvantages of bipahase (4*3=12 Marks) PART D Answer Any Two Full questions 12. a)Explain SONET layers(5 Marks) b)explain scrambling techniques.(4 Marks) 13. Describe different digital signal encoding scheme. Represent the digital data 1100000000110000010 with the help of neat diagrams.(9 Marks) 14. explain the characteristics of statistical TDM(9 marks) (18 Marks) PART E Answer Any four Full questions 15. Explain how error detection is done using CRC. Implement the above scheme for the message 1010001101 and generator polynomial x5+x4+x2+1(10 Marks) 16.a) explain types of errors(4 marks) b) explain synchronous transmission(6 Marks) 17.Explain spread spectrum techniques(10 Marks) 18. What are virtual circuit networks? Explain the characteristics of virtual circuit networks (10 Marks) 19.a)find the minimum hamming distance of the following coding scheme Dataword 00 01 10 11 Codeword 00000 01011 10101 11110 (4 Marks) b)Explain forward error correction and hamming distance (6 Marks) 20. a)Explain datagram networks(5 marks) b) explain structure of packet switch networks(5 marks) (4*10=40 Marks) Studoob.in - Where Learning is Entertainment

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APJ ABDULKALAM TECHNOLOGICAL UNIVERSITY FIFTH SEMESTER B.TECH EXAMINATION, DECEMBER 2017 DEPARTMENT: COMPUTER SCIENCE AND ENGINEERING SUBJECT:CS307 DATA COMMUNICATIN TIME: 3HOURS MAX MARKS:100 SCHEME OF EVALUATION 1. 2. andwidth B= Fh-f B=800-100=700 Hz 3. db= 10log10 p2/p1 = 10 log1080/100 4. Physical Description A communication satellite is, in effect, a microwave relay station. It is used to link two or more ground-based microwave transmitter/receivers, known as earth stations, or ground stations. The satellite receives transmissions on one frequency band (uplink), amplifies or repeats the signal, and transmits it on another frequency (downlink). A single orbiting satellite will operate on a number of frequency bands, called transponder channels, or simply transponders. wo common configurations for satellite communication. In the first, the satellite is being used to provide a point-to-point link between two distant ground-based antennas. In the second, the satellite provides communications between one ground-based transmitter and a number of ground-based receivers. Studoob.in - Where Learning is Entertainment

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. Applications The following are among the most important applications for satellites: • Television distribution • Long-distance telephone transmission • Private business networks • Global positioning 5. A.gnals travel through transmission media, which are not perfect. The imperfection causes signal impairment. This means that the signal at the beginning of the medium is not the same as the signal at the end of the medium. What is sent is not what is received. Three causes of impairment are attenuation, distortion, and noise. Attenuation Means loss of energy -> weaker signal When a signal travels through a medium it loses energy overcoming the resistance of the medium Ampliiers are used to compensate for this loss of energy by amplifying the signal. Measurement of Attenuation To show the loss or gain of energy the unit “decibel” is used. Studoob.in - Where Learning is Entertainment

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