Analog Communication System MCQs

Question 1

If input and output impedances are equal, doubled, its volume is increased by

Accepted Answer

1

Answer

2

Answer

3

Answer

3

Question 2

If output power of a radio receiver is decibel gain is given by

Accepted Answer

20 log1 12l

Answer

10 log10v2iv I

Answer

20 log10v1N2

Answer

20 logioviv

Question 3

The smallest change in sound intensity that can be detected by human ear is dB.

Accepted Answer

1

Answer

3

Answer

10

Answer

20

Question 4

The power required to produce a gain of 10 dB over 4 W of original power is watt.

Accepted Answer

40

Answer

80

Answer

0.4

Answer

8

Question 5

One decibel represents a power ratio of

Accepted Answer

1.26 : 1

Answer

10 : 1

Answer

20 : I

Answer

2 : 1

Question 6

A 4-W amplifier has a power gain of 40 dB. Its input power is

Accepted Answer

0.4 mW

Answer

0.4 W

Answer

0.1 W

Answer

1 W

Question 7

If the carriet of a 100 percent modulated AM wave is suppressed, the percentage power saving will be

Accepted Answer

66.66

Answer

50

Answer

150

Answer

100

Question 8

An amplitude modulated wave is

Accepted Answer

the sum of the carrier and the modulating wave

Answer

the difference between the carrier and the modulating wave

Answer

the product of the carrier and the modulating wave

Answer

sum of the carrier and its product with modulatine signal

Question 9

The modulation index of an AM wave is changed from 0 to 1. The transmitted power is

Accepted Answer

increased by 50 per cent.

Answer

unchanged

Answer

halved

Answer

doubled