Electronics and Communication Engineering - Communication Systems

11.
Which of the following antennas is circularly polarized?
Yagi-Uda
Parabolic reflector
Small circular loop
Helical
Answer: Option
Explanation:

The helical antenna is circularly polarized, i.e., its polarization is evenly divided between vertical and horizontal components.


12.
In colour TV system the colour sub carrier frequency is 4.43 MHz.
True
False
Answer: Option
Explanation:

Video monitor does not have RF tuner and IF amplifier stages.


13.
A transmitter power of 5 W is increased by 20 dB. The effective radiated power is
5 W
100 W
25 W
500 W
Answer: Option
Explanation:

or P = 500 W.


14.
The percentage saving in power of 100% modulated suppressed carrier AM signal is
100
75
66.6
50
Answer: Option
Explanation:

m = 1,

if carrier is suppressed then

.


15.
The maximum distance between television transmission and receiving antennas for reasonably good reception should be
less than 20 km
less than 100 km
less than 500 km
less than 1000 km
Answer: Option
Explanation:

Television transmission is governed by line of sight distance which is about 100 km or less.