GE 6252 Two Marks Questions & Answers - Unit 5

GE 6252 BASIC ELECTRICAL AND ELECTRONICS ENGINEERING 

UNIT 5 FUNDAMENTALS OF COMMUNICATION ENGINEERING 

TWO MARK QUESTIONS & ANSWERS 

Question 1: What is the difference between an analog and digital signals?

Answer: The differences between the analog and digital signals are tabulated:

Analog Signal	Digital Signal
An analog signal is continuous sine waves that keep changes with a time period. Analog Signal	A digital signal is a square wave that carries binary data and has discrete values. Digital Signal
The example of an analog signal is the human voice.	The example of a digital signal is the data transmission in a computer.

Question 2: Sketch the block diagram of the basic communication system.

Answer: The block diagram of the basic communication system is shown below:

Block diagram of the basic communication system

Question 3: What is the need for modulating the information signal?

Or

Mention the advantages of transmission of the modulated signal compared to an unmodulated signal.

Answer: The need or advantages of modulation of the information signal are,

• Ease of radiation,
• Increase in the distance of communication,
• Reduction in antenna height,
• Avoids mixing of signals,
• Multiplexing,
• Increase in the quality of signal reception.

Question 4: What is meant by modulation and demodulation?

Answer:

Modulation: It is a process by which the frequency of the signal to be transmitted is increased.

Demodulation: It is a process by which the message or information is retrieved from the transmitted modulating signal.

Question 5: State the basic functions of a communication satellite.

Answer: The basic functions of a communication satellite are,

• It provides point to multi-point communication,
• It performs the function of radio repeater or relay station.

Question 6: Draw the general structure of the satellite communication system.

Answer: The general structure of the satellite communication system is shown below:

General structure of the satellite communication system

Question 7: State the functions of a satellite transponder.

Answer: The functions of a satellite transponder are, 

• Reception of uplink signals,
• Frequency translation,
• Amplification of signals,
• Retransmission of downlink signals.

Question 8: Give typical values of uplink and downlink frequency in satellite communication.

Answer:

Uplink frequency – 6GHz / 14GHz.

Downlink frequency – 4GHz / 12GHz.

Question 9: What is a facsimile (FAX)?

Answer: Facsimile is an electronic system used to transmit and receive printed matter like text, pictures, graphics, and drawings. Facsimile uses the regular telephone lines and handles black and white levels only.

Question 10: What are the applications of microwave communication?

Answer: The microwave communications are used for,

• Telephone networks,
• In broadcast and television systems,
• Communication application in railways.

Question 11: Define Total Internal Reflection.

Answer: It is by the total internal reflection that the light rays propagate through the optical fiber.

If the light ray traveling in the core of higher refractive index is incident at the core-cladding interface with an angle of incidence, with respect to the normal, greater than the critical angle, it will be reflected back to the core. This phenomenon is called Total Internal Reflection.

Also, Read

GE 6252 - Two Marks Questions & Answers - Unit 1

GE 6252 - Two Marks Questions & Answers - Unit 2

GE 6252 - Two Marks Questions & Answers - Unit 3

GE 6252 - Two Marks Questions & Answers - Unit 4