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Data Communication Questions

Explain a data communication model with block diagram.

Distinguish between half-duplex and full-duplex transmission modes.

What is OSI model? Write the different layers in OSI model.

Sketch some possible topologies for a point-to-point subnet principle.

What are the advantages of a multipoint connection over a point-to-point connection?

Define periodic signal. Describe Fourirer series representation of a periodic signal.

What is topology? Describe the advantages and disadvantages of ring topology.

Consider a noiseless channel with a bandwith of 2000Hz transmitting a signal with four signal levels. Find the maximum bit rate of this channel.

What is signal? Explain it with time domain concepts.

Distinguish between a low-pass channel and a band-pass channel.

What is noise? Describe different catagories of noise in brief.

The power of a signal is 10mW and the power of the noise is 1uW; what are the values of SNR and SNRdB?

Define channel capacity. What key factors affect channel capacity?

Encode the digital signal 01001110 with following techniques:

i0 NRZ-L        ii) Manchester             iii) Bipolar AMI          iv) Pseudoternary

Discuss about Delta Modulation technique. What are the advantages of Delta Modulation technique over Pulse Code Modulation?

Discuss different techniques of analog encoding of digital data.

What is multiplexing? Describe the goals of multiplexing?

Five channels, each with a 140-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 5-kHz between the channels to prevent interference?

Define Spread Spectrum and explain how Direct Sequence Spread Spectrum technique achieves bandwidth spreading.

Write some advantages of optical fiber over twisted-pair and coaxial cable.

What is TSI and its role in a time-division switching?

Discuss the transmission of the packets using the datagram approach to packet switching.

What is a crosspoint in a crossbar switch?

What is ATM? Why are ATM cells 53 bytes long?

What is data communication? Why protocol is necessary in data communication?

Sketch some possible topologics for a multipoint subnet principle.

Define network. What are the criteria necessary for an efficient network? Explain.

What is a De-jure standard? Give an example of one.

Write some names of different Standards Organization.

Write the name of the layers in OSI model. Discuss briefly the function of a Data Link and Application layer in OSI model.

Define periodic signal. What are the three important characteristics of periodic signal.

Explain time-domain and frequency-domain representation of a signal with suitable example.

A telephone line normally has a bandwidth of 3000 Hz. The Signal to noise ratio is usually 3162. Find the maximum capacitiy of this channel.

Define Scrambling and give its purpose.

What is Liine coding? Write its classification.

Encode the digital signal 01001110 with following techniques :

  1. i) NRZ-L ii) NRZ-I iii) Bipolar       iv) Manchester.

How analog signal can be converted into PCM digital code? Show it in figure.

What is multiplexing? What are the three major mmultiplexing techniques?

Distinguish between synchronous and statistical TDM.

Define Spread Spectrum and explain how Direct Sequence Spread Spectrum (DSSS) technique achieves  bandwidth spreading.

What do you mean by the process of modulation? Why is iit necessary for the transmission of interlligence?

Explain the term bandwidth. Why is it useful?

Define switch. Compare space-division and time-division switches.

What is cross-point in a crossbar switch?

Discuss the transmission of the packets using the datagram approach of packet switching.

What are the limitation of using a circuit-switching network for data transmission?

Compare the two methods of serial transmission. Discuss the advantages of each.

Write some advantages of optical fiber over twisted-pair and coaxial cable.

How do guided media differ from unguided media?

What are some major advantages and disadvantages of microwave transmission?

What do you mean by communication of data? Sketch the components that are typically found in such communication model.

Differentiate between the half duplex and full duplex modes of data transmission. Which mode of data transmission is suitable for communication between a terminal and a computer-why?

Why are protocols needed? Briefly describe the key elements of a protocol.

Sketch some possible topologies for a point to point subnet principle.

Define bit rate and baud rate.

Write the OSI layers. Discuss briefly the function of a network layer  in OSI model.

Define channel capacity and list the key factors those affects channel capacity.

A periodic signal has a bandwidth of 40  Hz. The highest frequency is 80 Hz. What is the lowest frequency? Draw the spectrum if the signal contains all frequencies of the same amplitude.

Why multiplexer is used in data communication.

Explain briefly FDM multiplexing and demultiplexing process.

Defiine Frequency Hopping Spread Spectrum and explain how it achieves bandwidth spreading.

Assume that a voice channel occupies a bandwidth of 4 kHz. We need to combine three voice channels into a link with a bandwidth of 12 kHz form 20 to 32 kHz. Show the configuration, using the frequency domain. Assume there is no guard band.

Classify different types of transmission media.

What is an optical fiber? Write some advantages and disadvantagesof optical fiber.

Explain the process of delta modulation. Write its advantages over PCM.

Discuss synchronous data transmission with their advantages.

Define the terms modulation & demodulation.

Explain the action of a linear diode detector in the reception of an amplitude modulated wave.

Discuss different techniques of analog encoding of digital data.

Explain the basic principle of heterodyning action and justify its significance.



Why switching is needed?

Explain the circuit swathing network with its associated diagram.

What are the limitations of crossbar switch? How the limitations can be overcome?

Explain the fabrication process of Banyan Switch with its associated diagram.

What is a parity bit? Distinguish between even and odd parity.

Discuss the concept of redundancy in error detection and correction.

Generate CRC code for the data word 110101010 using the divisor 10101.

Discuss stop and wait mechanism for error control. What are the disadvantages of this mechanism?

What kind of error is undetectable by the checksum?

Define physical topology. Name four basic network topologies and cite an advantage of each type.

What is jitter? Briefly explain the types of line configuration in data communication.

Define protocols. Describe the types of data flow in data communication with examples.

Five devices are arranged in  a bus, ring, mesh and star topology. Discuss the consequences if a connetion fails for each networks.

Define logical connection in protocol layering. State the principles of protocol layering.

Briefly describe the functions of data link and network layers of TCP/OP protocol suite.

Discuss the encapsulation process at the surce host in TCP/IP protocol suite.

Suppose two computers are connected wia two switch and a touter. How many times physical and logical addresses will change if one computer sends a frame to another?

Define latency. What are the factors on which data rate depends in data communication?

How the bit rate limit and signal levels of a channel can be determined? The powers of a signal and noise are 10m W and 1  u W. What are the values of SNR and SNRdB?

Diofferentiate between block coding and scrambling. Describe bipolar line coding scheme with example.

Explain B8ZS scrambling technique with diagram.

What is composite signal? Diifferentiate between synchronous and asynchronous transmission.

Define analog transmission. Explain FSK convrersion technique in details.

What is carrier signal? Which of the three DAC techniques is more subceptibble to noise? Defend your answer.

How analog signal can be converted into PCM digital code? Show it in figure.

Define multiplexing. Describe differences between synchronous and statistical TDM.

What is spread spectrum? Explain how Direct Sequence Spread Spectruum achieves bandwidth spreading.

Define guard band in FDM. You have digital medium with data fate of 10Mbps. How many 64bps voice channels can be carried by this medium if we use DSSS with Barker sequence?

Define core and chadding. Explain the modes for propagating light along optical channel.

What is the function of the twisting in twisted-pair cable? Write some characteristics and applications of radio propagation.

Describe several propagation ways ofr unguided signals with examples.

What is the minimum Hamming distance? If we want to be able to detect two bit errors, what should be the minimum Hamming distance?

Given the dataword 101001111 and the divisor 10111, show the generation and checking of the codeword at the sender and r receiver site respectively.

Describe the procedure to calculate the traditional checksum both at the sender and receiver site.

In CRC, if the dataword is 5bits and the codeword is 8 bits how many 0s need to be added to the dataword to make the dividend? What is the size of the remainder? What is the size of the divisor?

Differentiate between a circuit switched network and a packekt-switched network.

Discuss the data transmission process in   a circuit-swritched network with example.

Draaw the configuration diagram of a three stage space-division switch with N=60, where 5 crossbars at the first and third stages and 4 crossbars at the middle stage. Also calculate the total number of crosspoints.