Communication Systems

Abstract

Simple communication is as old as human being’s existence on earth.

Questions

Fill in the blanks:

• 1. Communication is the process of __________ signals from one place to another.

• 2. The range of medium frequencies is __________.

• 3. Wavelength of ultra-high frequencies is __________.

• 4. In communication, the antenna dimensions should be of the order of __________ of the signal that is transmitted.

• 5. The total power in the modulated (AM) wave is expressed as __________.

• 6. The expression for current in amplitude modulation is __________.

• 7. Modulation index of FM is __________.

• 8. The master oscillator generates __________ carrier frequency.

• 9. The performance of AM receiver is improved by a technique known as __________.

• 10. The function of quantizer in receiver has to take a decision about __________ of a pulse.

Short questions

• 1. What is the difference between analog and digital signals?

• 2. What is the difference between ASK, FSK and PSK.

• 3. What is modulation?

• 4. What are the types of analog modulation?

• 5. Write the expression for modulation index in AM.

• 6. Write down the mathematical expression for a FM wave.

• 7. What are the advantages of FM over AM?

• 8. Compare FM and PM.

• 9. State sampling theorem.

• 10. Define the following terms:

  • (a) Pulse amplitude modulation (PAM).

  • (b) Pulse width modulation (PWM).

  • (c) Pulse time modulation (PTM).

  • (d) Pulse code modulation (PCM).

• 11. Describe briefly ASK, FSK and PSK.

Long questions

• 1. Explain briefly the need for modulation.

• 2. Draw the block diagram of communication system and explain its operation.

• 3. Explain amplitude and frequency modulation .

• 4. Describe briefly PAM, PCM, PPM and PDM.

• 5. Describe briefly about the data transmission.

• 6. Draw the block diagram arrangement of an AM transmitter and explain its operation.

• 7. Explain about the superheterodyne receiver with a neat block diagram.

• 8. Draw the block diagram of FM transmitter and explain its operation.

• 9. Draw the block diagram of FM receiver and explain its operation.

• 10. Explain about the radar system with a neat block diagram.

• 11. Draw the block diagram of modem and explain its operation.

• 12. Explain the satellite communication system with a neat block diagram.

• 13. Explain about the low power and high power AM transmitter with a neat block diagram.