CET Communication Systems & RF 3

Question 1

What is the impedance of a standard coaxial cable commonly used in RF systems?

Accepted Answer

50 ohms

Answer

25 ohms

Answer

100 ohms

Answer

300 ohms

Question 2

What type of antenna radiates equally in all horizontal directions?

Accepted Answer

Omnidirectional antenna

Answer

Yagi antenna

Answer

Parabolic dish

Answer

Log-periodic antenna

Question 3

What does the decibel (dB) measure in RF systems?

Accepted Answer

A logarithmic ratio between two power levels

Answer

Absolute power in watts

Answer

Signal frequency in Hz

Answer

Antenna gain in milliwatts

Question 4

In a PLL (Phase-Locked Loop) frequency synthesizer, what component compares the reference and feedback frequencies?

Accepted Answer

Phase detector

Answer

VCO

Answer

Low-pass filter

Answer

Frequency divider

Question 5

Which multiplexing method assigns each user a dedicated time slot in a shared channel?

Accepted Answer

TDMA

Answer

FDM

Answer

CDMA

Answer

OFDM

Question 6

What is the primary cause of multipath fading in RF communication systems?

Accepted Answer

Multiple signal reflections arriving at the receiver with different delays

Answer

Thermal noise in the receiver

Answer

Transmitter power fluctuations

Answer

Antenna polarization mismatch

Question 7

What is the purpose of an RF circulator in a communication system?

Accepted Answer

To route RF energy from one port to the next in a single direction

Answer

To amplify signals in all directions

Answer

To convert RF to DC power

Answer

To divide a signal equally among multiple outputs