Analog Communication System MCQs

Question 1

Which one of the following is an indirect way of generating EM.?

Accepted Answer

Armstrong modulator

Answer

Varactor diode modulator

Answer

Reactance FET modulator

Answer

Reactance bipolar transistor modulator

Question 2

When ma is the depth of modulation and E, is the carrier voltage amplitude, magnitude of side bands is given by

Accepted Answer

a c

Answer

2 tria.Ec

Answer

mEcm .

Answer

Em,,.E

Question 3

When the modulation index of an amplitude modulated wave is changed from 0 to 1, the transmitted power will

Accepted Answer

increase by 50%

Answer

remain unchanged

Answer

decrease by 50%

Answer

increase by 100%

Question 4

Which one of the following cannot be used to remove the unwanted side band in SSB?

Accepted Answer

Balanced modulator

Answer

Phase shift devices

Answer

Filters

Answer

All of the above

Question 5

If Em be the peak value of the modulating voltage and Er be the peak value of carrier voltage, then modulation index, is given by

Accepted Answer

M = K Em

Answer

M = K EmEr

Answer

M K ?Er

Answer

M = K E

Question 6

A balanced modulator circuit uses

Accepted Answer

two identical triodes

Answer

two identical diodes

Answer

two diodes with different V-1 characteristics

Answer

two triodes with different V-I characteristics

Question 7

A CW transmitter radiates

Accepted Answer

unmodulated RF carrier

Answer

modulated RF carrier

Answer

both (a) and (b) above

Answer

none of the above

Question 8

A buffer amplifier is

Accepted Answer

a cathode follower stage

Answer

a double-tuned amplifier

Answer

a high gain dc amplifier

Answer

none of the above

Question 9

A 3A modulation is sometimes used to

Accepted Answer

simplify the frequency stability problem in reception

Answer

allow thereceiver to have a frequency synthesizer

Answer

reduce the bandwidth required for transmission

Answer

reduce the power that must be transmitted