Analog Communication System MCQs

Question 1

The modulation index of a AM is to be measured using an oscilloscope. In this arrangement

Accepted Answer

modulatedsignal is connected to Y-input and modulating signal to X-input

Answer

modulated signal and modulating signal both are connected to Y-input of oscilloscope

Answer

modulated signal and modulating signal both are connected to X-input of oscilloscope

Answer

modulated signal is connected to X-input and modulating signal to Y-input

Question 2

An amplitude modulated current is given by i = 10 11 + 0.5 sin 6280 t] sin (3.14 x 105)t. The modulation index of the wave is

Accepted Answer

0.5

Answer

0.1

Answer

10%

Answer

1

Question 3

When Pc is the power of the unmodulated signal and m is the modulation index then power of the modulated signal is given by

Accepted Answer

m

Answer

mPc

Answer

m2

Answer

m1

Question 4

For bradcasting purpose, full AM signal is preferred to SSSB signal because

Accepted Answer

detection of full AM is simpler

Answer

it requires large bandwidth

Answer

generation of full AM is easier

Answer

none of the above

Question 5

In amplitude modulation if modulation index is more than 1 than

Accepted Answer

the wave will get distorted

Answer

the bandwidth will increase

Answer

there will be interference with other signals

Answer

efficiency of transmission will improve

Question 6

In grid bias modulation system the power required for modulating amplifier,

Accepted Answer

is small as compared to that for plate modulation

Answer

is negligibly low since grid is negative

Answer

is large as compared to that for plate modulation

Answer

is almost the same as compared with Plate modulation

Question 7

An amplitude modulated receiver uses a diode detector for demodulation. This enables it satisfactorily to receive

Accepted Answer

A3 H

Answer

A3 J

Answer

A3 A

Answer

A3 B

Question 8

Audio frequency range lies between

Accepted Answer

20 Hz and 20 kHz

Answer

20 kHz and 200 kHz

Answer

2 MHz and 20 MHz

Answer

20 MHz and 200 MHz

Question 9

Vestigial side band is most commonly used in

Accepted Answer

Television transmission

Answer

Radio transmission

Answer

Telephony

Answer

All of the above