JNTU
JNTU B.Tech II DATA COMMUNICATION Previous Question Paper (April - 2018 - R15)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART- A
What is the difference between serial and parallel data transmission?
Answer
In parallel transmission, multiple bits are sent simultaneously over separate wires, whereas in serial transmission, bits are sent one after another over a single channel. Parallel transmission is faster over short distances, while serial transmission is more cost-effective and suitable for long-distance communication.
Determine the minimum bandwidth, baud and bandwidth efficiency of ASK with a bit rate of 200 bps.
Answer
For ASK (Amplitude Shift Keying), the baud rate is equal to the bit rate, and the minimum bandwidth is equal to the baud rate.
The bandwidth efficiency is the ratio of bit rate to bandwidth:
Define velocity factor and dielectric constant.
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Distinguish between balanced and un-balanced transmission lines.
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Where is a telephone system in a local loop?
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What are the three categories of transmission parameters?
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What is false handoff? What is an interference avoidance scheme?
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What is meant by odd parity, even parity, marking parity and spacing parity.
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What is the purpose of digital service unit?
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Define modem synchronization and list its functions.
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PART- B
Briefly describe the seven layers of OSI protocol hierarchy.
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Describe the principles of ASK and FSK? Compare them.
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List and briefly describe the four transmission modes.
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Compare QPSK and QAM modulations.
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Describe open wire transmission lines.
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Determine the characteristic impedance for a coaxial cable with inductance L=0.2 µH/ft and capacitance C= 16Pf/ft.
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Describe the principle of FDM with a block diagram.
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Draw the block diagram of PCM-TDM system and explain.
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Describe dual-tone multifrequency and multifrequency signaling and where they are used.
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Compare cordless telephone and a standard telephone.
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Describe attenuation distortion and envelope delay distortion.
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Describe C-message noise weighting and state its significance.
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Describe TDMA scheme used with USDC.
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Describe CDMA format used with INTERIM standard 95.
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Determine the BCC for the following data and CRC generating polynomials: Data G(x) = x7 + x4+ x2+ x0=10010101 CRC P(x) = x5+ x4+ x1+ x0=110011.
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List and describe the basic blocks of asynchronous voice band modem.
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Describe the AT command set.
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List and describe the four modem operation modes.
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List and describe the characteristics of synchronous voice band modem.
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