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Electronics and Communication Engineering - Communication Systems

Exercise : Communication Systems - Section 4
41.
FSK is a system involving
pulse modulation
frequency modulation
amplitude modulation
phase modulation
Answer: Option
Explanation:

FSK, i.e., frequency shift keying is a system of frequency modulation.

42.
A 200 Hz sound wave is to be transmitted by a 1000 kHz radio wave using frequency modulation. The instantaneous frequency variation will be
100 times a second
200 times a second
400 times a second
1000 times a second
Answer: Option
Explanation:

The instantaneous frequency variation is equal to frequency of audio signal.

43.
In a TV studios, flying spot scanner is a device for
mixing video and audio signals
telecasting feature films
live telecast of outdoor programs
telecast of indoor music programs
Answer: Option
Explanation:

It is used to telecast feature films. Flying spot scanner uses a special low persistence high brightness cathode ray tube.

44.
A broadcast radio transmitter radiates 5 kW when the modulation percentage is 60. How much of this is carrier power?
6.66 kW
5 kW
4.9 kW
4.23 kW
Answer: Option
Explanation:

m = 1,

45.
A device has two resistances 300 Ω and 200 Ω respectively. The noise voltages due to these two resistance calculated separately are 5.38 μV and 4.38 μV respectively. When both of them are used together, the noise voltage will be
9.76 V
1 μV
23.56 μV
6.94 μV
Answer: Option
Explanation:

.

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