Sunday, 27 April 2014


B.Tech I Semester Examinations Questions

DATACOMMUNICATIONSYSTEMS.pdf (Size: 60.08 KB / Downloads: 66)

1. (a) Explain the classi cations of USDC radiated power?
(b) Describe the basic concepts and outline the speci cations of IS-95. [8+8]

2. (a) Describe twisted pair transmission lines?
(b) Why is single-mode propagation impossible with graded-index optical bers?
Explain? [8+8]

3. (a) Distinguish between error correction and error detection by retransmission?
(b) Describe the basic functions of a digital service unit? [8+8]

4. (a) Describe the di erences between magnitude-only PCM codes and sign-magnitude PCM codes.
(b) List and explain the various frame synchronization techniques? [8+8]

5. (a) Where in a telephone system is the local loop?
(b) Describe nonlinear, transmittance and coupling crosstalk? [8+8]

6. (a) Explain IBMs binary synchronous communications protocol?
(b) Describe IBM's 83B asynchronous data link protocol? [8+8]

7. (a) What are data communication standards and why they are needed?
(b) Determine the information capacity in bps for a circuit with a 100-KHz band - width and a signal-to-noise ratio of 40dB(10,000). [8+8]

8. Describe the satellite orbits and orbital patterns?

1. Discuss the features two asynchronous data link protocols XMODEM and YMO-DEM? [16]

2. (a) What is Topology? Explain briey about network Topologies.
(b) Explain the probability of error and bit error rate? [8+8]

3. (a) Explain the features and multiplexing of SONET?
(b) Describe the di erential PCM? [8+8]

4. (a) Explain the di erent types of metallic transmission lines?
(b) State snell's law for refraction and outline its signi cance for optical bercables. [8+8]

5. (a) What is the di erence between a station busy signal and an equipment busy signal?
(b) What is the reference frequency for attenuation distortion? [8+8]

6. (a) Discuss the features of modem equalizers?
(b) Explain the ITU-T modem recommendations? [8+8]

7. (a) Outline the advantages and disadvantages of PCSS over terrestrial cellular telephone systems?
(b) Briey describe the E-TDMA scheme? [8+8]

8. (a) Explain the sky wave propagation?
(b) Determine the reaction coe cient for a reected power of 0.001W and an incident power of 0.008W.


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