Optical Communication Set 8

Electrical Engineering

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This set of Optical Communication Multiple Choice Questions & Answers (MCQs) focuses on Optical Communication Set 8

Q1 | A regenerative repeater is called as
  • repetitive repeater
  • regenerator
  • attenuator
  • gyrator
Answer: regenerator
Explaination:
when digital transmission techniques are used, the repeater also regenerates the original digital signal in the electrical signal before it is retransmitted as an optical signal via a line transmitter.
Q2 | How many encoding schemes are used in optical fiber communication system design requirements?
  • three
  • one
  • two
  • four
Answer: two
Explaination:
encoding schemes are used for digital transmission of data. these are bi- phase and delay modulation codes. they are also called as manchester and miller codes respectively.
Q3 | In                  the optical channel bandwidth is divided into non-overlapping frequency bands.
  • time division multiplexing
  • frequency division multiplexing
  • code division multiplexing
  • de-multiplexing
Answer: frequency division multiplexing
Explaination:
in fdm, the non-overlapping frequency bands are divided to the individual frequencies. these individual signals can be extracted from the combined fdm signal by electrical filtering at the receiver terminal.
Q4 | A multiplexing technique which does not involve the application of several message signals onto a single fiber is called as
  • time division multiplexing
  • frequency division multiplexing
  • code division multiplexing
  • space division multiplexing
Answer: space division multiplexing
Explaination:
in sdm, each signal channel is carried on a separate fiber within a fiber bundle or multi-fiber cable form. the cross coupling between channels is negligible.
Q5 | Which of the following is not an optical fiber component?
  • fiber
  • connector
  • circulator
  • detector
Answer: circulator
Explaination:
circulator is a device used in electromagnetic theory. all others are optical components.
Q6 |                 technique involves an increase in the number of components required.
  • time division multiplexing
  • space division multiplexing
  • code division multiplexing
  • frequency division multiplexing
Answer: space division multiplexing
Explaination:
sdm involves good optical isolation due to the negligible cross coupling between channels. it uses separate fiber and thus requires more number of components.
Q7 | Time division multiplexing is inverse to that of frequency division multiplexing.
  • true
  • false
Answer: true
Explaination:
tdm involves distribution of channels in time slots whereas fdm involves bands that are run on different frequencies.
Q8 | SONET stands for                        
  • synchronous optical network
  • synchronous operational network
  • stream optical network
  • shell operational network
Answer: synchronous optical network
Explaination:
sonet stands for synchronous optical network. frame relay uses sonet to physically transmit data frames over a frame relay network as sonet is cheaper and provides better network reliability than other carriers.
Q9 | In SONET, STS-1 level of electrical signalling has the data rate of                    
  • 51.84 mbps
  • 155.52 mbps c) 2488.320 mbps d) 622.080 mbps
Answer: 51.84 mbps
Explaination:
sts-1 level provides the data rate of 51.84 mbps, sts-3 provides a data rate of 155.52 mbps, sts-12 provides a data rate of 622.080 mbps and sts-48 provides a data rate of 2488.320 mbps.
Q10 | The path layer of SONET is responsible for the movement of a signal                    
  • from its optical source to its optical destination
  • across a physical line
  • across a physical section
  • back to its optical source
Answer: across a physical line
Explaination:
the path layer in sonet is responsible for finding the path of the signal across the physical line to reach the optical destination. it is ideally expected to find the shortest and the most reliable path to the destination.
Q11 | The photonic layer of the SONET is similar to the                      of OSI model.
  • network layer
  • data link layer
  • physical layer
  • transport layer
Answer: physical layer
Explaination:
the photonic layer in sonet is like the physical layer of the osi model. it is the lowest layer among the four layers of sonet namely the photonic, the section, the line, and the path layers.
Q12 | In SONET, each synchronous transfer signal STS-n is composed of                      
  • 2000 frames
  • 4000 frames
  • 8000 frames
  • 16000 frames
Answer: 8000 frames
Explaination:
sonet defines the electrical signal as sts-n (synchronous transport signal level-n) and the optical signal as oc- n (optical carrier level-n). the building block of sonet is the sts-1/oc-1 signal, which is based on an 8-khz frame rate and operates at 51.84 mbps.
Q13 | Which one of the following is not true about SONET?
  • frames of lower rate can be synchronously time-division multiplexed into a higher-rate frame
  • multiplexing is synchronous tdm
  • all clocks in the network are locked to a master clock
  • sts-1 provides the data rate of 622.080mbps
Answer: sts-1 provides the data rate of 622.080mbps
Explaination:
in sonet, sts-n stands for synchronous transport signal level-n. sts- 1 level provides the data rate of 51.84 mbps, and sts-12 provides a data rate of 622.080 mbps.
Q14 | A linear SONET network can be                  
  • point-to-point
  • multi-point
  • both point-to-point and multi-point
  • single point
Answer: both point-to-point and multi-point
Explaination:
synchronous optical network (sonet) is basically an optical fiber point- to-point or ring network backbone that provides a way to accommodate additional capacity as the needs of the organization increase to multipoint networks.
Q15 | Automatic protection switching in linear network is defined at the                
  • line layer
  • section layer
  • photonic layer
  • path layer
Answer: line layer
Explaination:
the line layer in sonet operates like the data link layer in the osi
Q16 | A unidirectional path switching ring is a network with                      
  • one ring
  • two rings
  • three rings
  • four rings
Answer: two rings
Explaination:
one ring is used as the working ring and other as the protection ring in which each node is connected to its respective adjacent nodes by two fibers, one to transmit, and one to receive.
Q17 |                          is a multi-functional element of optical network.
  • hop
  • optical node
  • wavelength
  • optical attenuation
Answer: optical node
Explaination:
an optical node is a multi- functional element which acts as a transceiver unit capable of receiving, transmitting and
Q18 | A signal carried on a dedicated wavelength from source to destination node is known as a
  • light path
  • light wave
  • light node
  • light source
Answer: light path
Explaination:
a light path is a dedicated path from a source to a destination. the data can be sent over the light paths as soon as connections are set up. a controlling mechanism is present to control the data flow.
Q19 | The fundamentals of optical networking are divided into                areas.
  • two
  • one
  • four
  • three
Answer: three
Explaination:
the fundamentals divided into three areas contain mainly optical network terminology. the other two areas include functions and types of optical network node and switching elements and the wavelength division multiplexed optical networks.
Q20 | The network structure formed due to the interconnectivity patterns is known as a
  • network
  • struck
  • topology
  • d-pattern
Answer: topology
Explaination:
a topology is a combination of patterns interconnected to each other. it provides connection patterns to users at different places. it embarks on the principle of multi-usability.
Q21 | In the                      topology, the data generally circulates bi-directionally.
  • mesh
  • bus
  • star
  • ring
Answer: bus
Explaination:
in a bus topology, data is input via four port couplers. the couplers couples and stations the data bi-directionally and are removed from the same ports.
Q22 | The ring and star topologies are combined in a                  configuration.
  • mesh
  • fringe
  • data
  • singular
Answer: mesh
Explaination:
the mesh configuration is a combination of ring and star topologies. it is referred to as full-mesh when each network node is interconnected with all nodes in the network.
Q23 | The full-mesh configuration is complex.
  • false
  • true
Answer: true
Explaination:
the full-mesh topology is a
Q24 | How many networking modes are available to establish a transmission path?
  • three
  • one
  • two
  • four
Answer: two
Explaination:
there are two networking modes often referred to the networking. these are connection-oriented and connectionless networking modes. these include an end-to-end and bidirectional communication environment between source and destination.
Q25 | Packet switching is also called as
  • frame switching
  • cell switching
  • trans-switching
  • buffer switching
Answer: cell switching
Explaination:
in packet or cell switching, messages are sent in small packets called cells. cells from different sources are statistically multiplexed and are sent to the destinations.
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