CET Communication Systems & RF 2

Question 1

What is the primary advantage of using FM over AM for voice communications?

Accepted Answer

FM provides better noise immunity

Answer

FM has greater range

Answer

FM uses less bandwidth

Answer

FM requires simpler receivers

Question 2

Which modulation technique encodes data by shifting the carrier signal's phase between discrete values?

Accepted Answer

PSK

Answer

ASK

Answer

FSK

Answer

QAM

Question 3

A transmitter operates at 150 MHz. What is the quarter-wave antenna length?

Accepted Answer

0.5 m

Answer

0.25 m

Answer

1.0 m

Answer

2.0 m

Question 4

What does VSWR of 1:1 indicate in an RF transmission line system?

Accepted Answer

Perfect impedance match with no reflected power

Answer

Maximum power reflection

Answer

Complete impedance mismatch

Answer

Signal attenuation of 50%

Question 5

In a superheterodyne receiver, what is the purpose of the IF stage?

Accepted Answer

To convert the signal to a fixed intermediate frequency for consistent filtering

Answer

To amplify the antenna signal directly

Answer

To demodulate the carrier

Answer

To suppress the local oscillator signal

Question 6

What is the function of a bandpass filter in an RF communication system?

Accepted Answer

Passes a specific range of frequencies while attenuating others

Answer

Blocks all frequencies

Answer

Converts RF energy to audio

Answer

Amplifies only low-frequency signals

Question 7

Which of the following describes the capture effect in FM receivers?

Accepted Answer

The receiver locks onto the stronger of two co-channel signals

Answer

Both co-channel signals are received equally

Answer

Weaker signals are amplified above the stronger

Answer

FM receivers reject all signals above threshold