Analog Communication System MCQs

Question 1

A FM discriminator changes

Accepted Answer

FM signal into AM signal

Answer

FM signal into FM signal of low frequency

Answer

FM signal into FM signal of high frequency

Answer

FM signal into PM signal

Question 2

A frequency multiplier circuit

Accepted Answer

is tuned to a harmonic of the input signal

Answer

operates class A

Answer

needs parasitic oscillations

Answer

is usually pulse modulated

Question 3

Which system is free from noise?

Accepted Answer

FM

Answer

AM

Answer

Both FM and AM

Answer

None of the above

Question 4

The frequency of the stereo sub-carrier signal in FM broadcasting is

Accepted Answer

38 kHz

Answer

19 kHz

Answer

50 IcHz

Answer

76 kHz

Question 5

One Angstrom of wavelength (I A?) equals

Accepted Answer

10-10m

Answer

10-8m

Answer

1(110m

Answer

1 tam

Question 6

In amplitude modulation

Accepted Answer

the amplitude of the carrier varies in accordance with the amplitude of the modulating signal

Answer

the amplitude of the carrier remains constant

Answer

the amplitude of the carrier varies in accordance with the frequency of the modulating signal

Answer

modulating frequency lies in the audio range

Question 7

The bandwidth of DSB suppressed carrier modulation system when the modulating frequency varies between 100 Hz and 5 kHz is

Accepted Answer

10 kHz

Answer

10 Hz

Answer

5 kHz

Answer

4.9 kHz

Question 8

In a 100% amplitude modulated signal, the power in the upper sideband when the carrier power is 100 watts and the modulation system is SSBSC is

Accepted Answer

25 watts

Answer

100 watts

Answer

50 watts

Answer

none of these

Question 9

The percentage saving in power of 100% modulated SSBSC amplitude modulated signal as compared to DSB signal is

Accepted Answer

83.33

Answer

100

Answer

66.66

Answer

150