2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Students can Download 2nd PUC Electronics Chapter 13 Modem Communication Systems Questions and Answers, Notes Pdf, 2nd PUC Electronics Question Bank with Answers, helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.

Karnataka 2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

2nd PUC Electronics Modem Communication Systems One Mark Questions and Answers

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 1.
What is cellular communication?
Answer:
Cellular communication is one that permits the user to link up with standard telephone systems and allows calls to any part of the world.

Question 2.
What is cell splitting?
Answer:
Cell splitting is dividing the entire geographical area into hexagonal shaped cells that fit together to form a honeycomb pattern.

Question 3.
Why the cells are in hexagonal shape during cell splitting?
Answer:
The cells are in hexagon shape because hexagonal shape approximates the circular pattern while eliminating the gaps present between adjacent cells.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 4.
What is the internet?
Answer:
Internet is worldwide interconnection of millions of computers by means of complex network which serves as an inexpensive communication medium.

Question 5.
What is a protocol?
Answer:
A protocol is a set of rules and procedures that will be used by the system for communication.

Question 6.
What is WWW?
Answer:
World wide web.

Question 7.
Define Wi-Fi.
Answer:
Wi-Fi is the trade name of the wireless local area networking technology.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 8.
What is Bluetooth?
Answer:
Bluetooth is a wireless technology standard for exchanging data over short distance from fixed and mobile devices.

Question 9.
What is a piconet?
Answer:
Pinconet refers to the linking of one Bluetooth device that serves as a master controller to a maximum of seven other Bluetooth slave services.

Question 10.
What is meant by fibre optic communication?
Answer:
Optical fibre communication uses light as the carrier of information to be transmitted.

Question 11.
What materials are commonly used for fibre optic cables?
Answer:
Glass or plastic.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 12.
What is a transponder?
Answer:
Transponder is a receiver-transmitter combination located on a satellite that takes an uplink signal and converts it into a downlink signal.

Question 13.
What is RADAR?
Answer:
Radar stands for Radio Detection and Ranging and it is a system used for detecting and determining velocity of a distant object.

2nd PUC Electronics Modem Communication Systems Two Marks Questions and Answers

Question 14.
Mention the advantages of cell phone systems.
Answer

  1. The frequency spectrum is utilized to the maximum by multiplexing methods.
  2. It is more reliable.
  3. The handsets become more compact with enhanced features.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 15.
Mention the uses of Internet.
Answer:

  1. Using internet, access to required information is easy, economical, reliable and fast.
  2. With E-mail, messages reach destination with in minutes.
  3. E-mail can be sent and received from any place.
  4. Using E-mail, message can be sent to several persons simultaneously.

Question 16.
What is ISP? Mention its role in computer networking.
Answer:
ISP is Internet service provider. ISP provides the software for communication over Internet. The ISP has one or more towers to which thousands of cables, modems are connected for the use of subscribers.

Question 17.
Mention a few types of protocols used in computer networking.
Answer:

  1. TCP-Transmission control protocol.
  2. IP- Internet protocol.
  3. FTP-File transfer protocol.
  4. HTTP- Hyper text transfer protocol.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 18.
What is URL? Mention its general format.
Answer:
URL is universal Resource locator. Each individual is given a unique address called URL. The format is WWW. User name a. host. Domain.

Question 19.
Mention the important techniques used for Bluetooth operation.
Answer:

  1. Frequency Hopping spread Spectrum (FHSS)
  2. Frequency shift Keying technique (FSK).

Question 20.
Mention few applications of fibre optic communication system.
Answer:

  1. Long-distance telephone and cable TV systems.
  2. To provide LAN connections.
  3. Closed-circuit TV systems used for security.
  4. Aircraft communication and controls.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 21.
Mention few applications of satellites.
Answer:

  1. Telecommunications.
  2. To transmit TV signals
  3. Global positioning services.

Question 22.
Distinguish between uplink and downlink signals.
Answer:
The transmission of a signal from an earth station to a satellite is called uplink. The retransmission of a signal from a satellite to an earth station is called the downlink.

Question 23.
Mention few applications of communication satellites.
Answer:

  1. Voice communication.
  2. TV and radio broadcast.
  3. Teleconferencing.
  4. Mobile communication.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 24.
Draw the diagram of satellite transponder system.
Answer:
2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems 1

Question 25.
Mention few applications of RADAR.
Answer:

  1. Location of enemy missiles, planes and ships.
  2. Defence weapons systems.
  3. Used as altimeters to measure height.
  4. Landing of planes in bad weather conditions.

2nd PUC Electronics Modem Communication Systems Three Marks Questions and Answers

Question 26.
List the additional features of 3G and 4G cell phone systems.
Answer:
Additional features of 3G and 4G phone systems are:

  1. Colour LCD screens
  2. Digital cameras
  3. E-mail, Games
  4. GPS, Bluetooth
  5. Internet access
  6. Video conferencing.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 27.
Explain call hand-off and frequency reuse used in cell phone system.
Answer:
Call hand-off is the process in which a call in progress is transferred from a radio channel of a cell site to a radio channel of another cell as a mobile phone user moves from one cell to another.

Frequency reuse is the process in which the same set of carrier frequencies are used in different cells that are geographically separated.

With a diagram, explain the operation of a communication satellite system.

Satellite acts as a relay station for earth sources. A transmission station sends the information to the satellite, which in turn retransmits to the receiving stations.

The original signal being transmitted from the earth station to the satellite is called uplink of 6 GHz The retransmitted signal from the satellite to the receiving station is called downlink of 4 GHZ frequency. Transponder is the transmitter-receiver combination in a transponder.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 28.
DrawalabdlleddiagramofBluetooth system.
Answer:
2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems 2

Question 29.
Compare Wi-Fl and Bluetooth.
Answer:

Wi-Fi Bluetooth
1. Access is point centered
2. Serves well in high-speed applications
1.Symmetrical between two Bluetooth devices.
2. Serves well in simple appli­cations.

Question 30.
With a diagram, explain the operation of a communication satellite system.
Answer:
Satellite acts as a relay station for earth sources. A transmission station sends the information to the satellite, which in turn retransmits to the receiving stations.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

The original signal being transmitted from the earth station to the satellite is called uplink of 6 GHz The retransmitted signal from the satellite to the receiving station is called downlink of 4 GH frequency. The transponder is the transmitter-receiver combination in a transponder.
2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems 3

Question 31.
Give a classification of RADAR systems.
Answer:
1. Doppler wave (CW) Radar

  • Doppler radar
  • FM radar
  • phased array radar.
  • planar array radar.

2 Pulsed Radar.

  • Moving target indicator (MTI) radar
  • Radar beacons.

2nd PUC Electronics C Programming Five Marks Questions and Answers

Question 32.
Draw the block diagram of a 2G cell phone system and briefly describe the function of each block.
Answer:
2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems 4
The RF section has transmitter and receiver circuits including mixer, local oscillator for channel selection, the receiver, low noise amplifiers and transmitter power amplifier.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

The baseband section contains the vocoder with it’s A/D converter and D/A plus a digital signal processor chip that handles many processing functions like baseband and intermediate frequency filtering, modulation, demodulation and mixing. The vocoder is a circuit which converts voice into digital format and compresses digital data.

An embedded controller handles all the digital control and signaling, hand offs and connection and identification of operations that takes place transparent to the subscriber. It also takes care of running display and key board and all other user functions such as number storage, auto-dialing and caller ID etc. The embedded controller is a fast 32 bit microprocessor with considerable RAM, ROM and flash memory.

Question 33.
List the sequence of operations involved in establishing a call from a cell phone.
Answer:

  1. The cell phone user operates power to the unit so that the transmitter and receiver are turned ON.
  2. The MTSO computer verifies whether the caller is a valid number for service.
  3. The user enters the number to be called via a keyboard.
  4. The user sends the number to be called by pressing the call button.
  5. The cell and MTSO search for an open channel and send frequency data to a cellular transceiver.
  6. The transmitter power is adjusted and handshake signals are exchanged, signifying that contact has been established.
  7. The MTSO calls the designated number and conversation takes place.
  8. If the mobile passes from one cell to another, call hand-off is done by the MTSO to maintain maximum signal strength.
  9. At the end of conservation, the call is terminated by pressing the power button again.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

Question 34.
Briefly explain different parts of an internet address.
Answer:
The format of internet address or universal Resource Locator is WWW. Username a host, domain.
WWW: World wide web is a server based application that allows the subscribers to access the services offered by the web. Usemame: It is the first part of the address that identifies the individual or computer on the network.

HOST: It is the second part of the address which may be a computer,user, a service provider etc. DOMAIN: It is the last part of the address which indicates the specific organization using the internet. Eg. Com, edu, net etc.

Question 35.
List the advantages and applications of Wi-Fi.
Answer:

  1. Wi-Fi is used to access the internet via hotspots with a laptop computer.
  2. It is one of the most reliable, flexible and affordable wireless networking technology.
  3. Wi-Fi allows cheaper deployment of local area network in outdoor areas like historical buildings.
  4. The price of chipsets for Wi-Fi continues to drop, making it an economical networking operation.
  5. The standard Wi-Fi device will work anywhere in the world.

Question 36.
Mention few applications of Bluetooth.
Answer:

  1. Cordless headsets for cellphones.
  2. Wireless communication between PCs or laptops.
  3. Wireless PC printer connections.
  4. Laptop-cell connections.
  5. Wireless audio headsets.
  6. Wireless digital camera-TV set connections.
  7. Dial-up internet access on personal computers.

Question 37.
With a neat block diagram, explain the operation of fiber optic communication.
Answer:
2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems 5
The information signal to be transmitted is first converted to digital format using Analog to Digital converter, which is compatible with the communication medium.

2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems

These digital pulses are then fed to a optical fibre cable which can transmit them over long distances. At the receiving end, a light sensitive device like a photocell is used to detect light pulses. It converts light into an electrical signal.

The receiver circuit processes the electrical signal to recover the original information.

Question 38.
Draw the block diagram of a Radar system and explain the function of each block.
Answer:
2nd PUC Electronics Question Bank Chapter 13 Modem Communication Systems 6

  • Transmitter: The radar transmitter produces high-frequency RF pulses and is transmitted into space by the antenna.
  • Duplexer: It switches the antenna between transmitter and receiver alternately. This is required because high power pulses of the transmitter will destroy the receiver if energy were allowed to enter the receiver.
  • Receiver: It amplifies and demodulates the received RF signals. It provides video signals on the output.
  • Radar antenna: The antenna transfers the transmitting signal to space with the required distribution and efficiency.

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