Communication System Multiple Choice Questions

 Electronics and Communication Multiple Choice Questions

1. In PCM if the transmission path is very long?

a. repeater stations are used

b. pulse width may be increased

c. pulse amplitude is increased

d. pulse spacing is reduced

2. Frequency shift keying is used mostly in?

a. radio transmission

b. telegraphy

c. telephony

d. none of these

3. Leak type bias is used in a plate modulated class C amplifier to?

a. increase the bandwidth

b. prevent excessive grid current

c. prevent tuned circuit damping

d. prevent overmodulation

4. The frequency of normal sound wave determines its?

a. quantity

b. echo

c. loudness

d. pitch

5. Which of the following is most likely to be found in an SSB transistor?

a. Class A, RF output amplifier

b. Class B, RF amplifier

c. tuned modulator

d. Class C, audio amplifier

6. A longwave AM Broadcast transmitter needs?

a. very small carrier power

b. very large carrier power

c. small carrier power

d. large carrier power

7. The term noise temperature is used for?

a. white noise source only

b. thermal noise source only

c. non-thermal noise source only

d. all of the above

8. The thermal noise is due to random?

a. motion of atoms and molecules

b. motion of free electrons

c. vibrations of atom about their mean position, inside the conducting medium

d. none of these

9. At high frequencies, which of the following types of noise become most important?

a. flicker noise

b. short noise

c. thermal noise

d. transit time noise

10. Which of the following is not uniformly distributed over all frequencies?

a. white noise

b. flicker noise

c. short noise

d.  thermal noise

Answers:

1. a

2. b

3. b

4. d

5. b

6. b

7. d

8. b

9. d

10. b

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