The colour of an object is decided by%!

The wavelength transmitted through it

Reflected colour for opaque object and wavelength transmitted through it for transparent objects

What is the purpose of peak clipper circuits in radio transmitters?%!

To regulate oscillator I/P voltage

SSB can be generated by%!

Good attenuation characteristics

In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then%!

Amplitude of distant sidebands remains constant

Amplitude of distant sidebands decreases

Amplitude of distant sidebands increases

Amplitude of distant sidebands remains constant

Amplitude of distant sidebands first increases, then decreases

The main function of a balanced modulator is to%!

Suppress carrier signal in order to create a single-sideband or double sideband

Produce balanced modulation of a carrier wave

Suppress carrier signal in order to create a single-sideband or double sideband

Limit noise picked by a receiver

In a TV receiver antenna the length of reflector rod%!

May be equal, more or less than that of dipole

In a FM receiver, amplitude limiter%!

Amplifiers low frequency signals

Reduces the amplitude of signals

Eliminates any change in amplitude of received FM signals

*$_In a FM receiver, amplitude limiter?

Amplifiers low frequency signals

Reduces the amplitude of signals

Eliminates any change in amplitude of received FM signals

*/*_In a TV receiver antenna the length of reflector rod?

May be equal, more or less than that of dipole

*/*_In Modulation, ‚Äö√Ñ√∫carrier‚Äö√Ñ√π is?

Speech voltage to be transmitted

Voltage with constant frequency, phase or amplitude

Voltage for which frequency, phase or amplitude is varied

*/*_In EM waves, polarization?

Results from longitudinal nature of waves

Is always vertical in an isotropic medium

Is due to transverse nature of waves

Results from longitudinal nature of waves

_ In EM waves, polarization$?

Results from longitudinal nature of waves

Is always vertical in an isotropic medium

Is due to transverse nature of waves

Results from longitudinal nature of waves

_ In Modulation, ‚Äö√Ñ√∫carrier‚Äö√Ñ√π is$?

Speech voltage to be transmitted

Voltage with constant frequency, phase or amplitude

Voltage for which frequency, phase or amplitude is varied

78 + Mcqs in Communication Systems in Electrical Engineering Page 1 McqOptions

1.	An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.%!
A.	102.3
B.	113
C.	70.2
D.	80.9
Answer» C. 70.2

Discussion

2.	Commercial Frequency deviation of FM is%!
A.	70 kHz
B.	75 kHz
C.	80 kHz
D.	65 kHz
Answer» C. 80 kHz

Discussion

3.	In case of low level amplitude modulation system, the amplifiers following the modulated stage must be%!
A.	Class C amplifiers
B.	Linear devices
C.	Non-linear devices
D.	Harmonic devices
Answer» C. Non-linear devices

Discussion

4.	For a low level AM system, the amplifiers modulated stage must be%!
A.	Linear devices
B.	Harmonic devices
C.	Class C amplifiers
D.	Non-linear devices
Answer» B. Harmonic devices

Discussion

5.	The colour of an object is decided by%!
A.	The reflected colour
B.	The wavelength transmitted through it
C.	Reflected colour for opaque object and wavelength transmitted through it for transparent objects
D.	None of the above
Answer» D. None of the above

Discussion

6.	What is the purpose of peak clipper circuits in radio transmitters?%!
A.	To prevent overmodulation
B.	To reduce bandwidth
C.	To increase bandwidth
D.	To regulate oscillator I/P voltage
Answer» B. To reduce bandwidth

Discussion

7.	Full duplex operation permits transmission in both directions at the same time.%!
A.	True
B.	False
Answer» B. False

Discussion

8.	SSB can be generated by%!
A.	Filter method
B.	Phase cancellation method
C.	Good attenuation characteristics
D.	All of the above
Answer» E.

Discussion

9.	In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then%!
A.	Amplitude of distant sidebands decreases
B.	Amplitude of distant sidebands increases
C.	Amplitude of distant sidebands remains constant
D.	Amplitude of distant sidebands first increases, then decreases
Answer» C. Amplitude of distant sidebands remains constant

Discussion

10.	A buffer amplifier is%!
A.	A double-tuned amplifier
B.	A high gain D.C. amplifier
C.	A cathode follower stage
D.	None of the above
Answer» C. A cathode follower stage

Discussion

11.	The main function of a balanced modulator is to%!
A.	Produce balanced modulation of a carrier wave
B.	Produce 100% modulation
C.	Suppress carrier signal in order to create a single-sideband or double sideband
D.	Limit noise picked by a receiver
Answer» C. Suppress carrier signal in order to create a single-sideband or double sideband

Discussion

12.	It is found that a ship to ship communication suffers from fading. This can be avoided by using%!
A.	Space diversity
B.	Frequency diversity
C.	Broad band antenna
D.	Directional antenna
Answer» C. Broad band antenna

Discussion

13.	For telegraphy the most commonly used modulation system is%!
A.	FSK
B.	Two tone modulation
C.	PCM
D.	Single tone modulation
Answer» B. Two tone modulation

Discussion

14.	Skip distance depends on time of day and angle of incidence.%!
A.	True
B.	False
Answer» B. False

Discussion

15.	In a TV receiver antenna the length of reflector rod%!
A.	Is the same as that of dipole
B.	Is less than that of dipole
C.	Is more than that of dipole
D.	May be equal, more or less than that of dipole
Answer» D. May be equal, more or less than that of dipole

Discussion

16.	For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as%!
A.	2E
B.	3E
C.	4E
D.	6E
Answer» D. 6E

Discussion

17.	A modem is classified as low speed if data rate handled is%!
A.	Upto 100 bps
B.	Upto 250 bps
C.	Upto 400 bps
D.	Upto 600 bps
Answer» E.

Discussion

18.	For attenuation of high frequencies we should use%!
A.	Shunt capacitance
B.	Series capacitance
C.	Inductance
D.	Resistance
Answer» B. Series capacitance

Discussion

19.	The maximum power output of a standard A earth station over the total band allocated to satellite communication is about%!
A.	0.5 kW
B.	8 kW
C.	20 kW
D.	50 kW
Answer» B. 8 kW

Discussion

20.	In a FM receiver, amplitude limiter%!
A.	Amplifiers low frequency signals
B.	Reduces the amplitude of signals
C.	Eliminates any change in amplitude of received FM signals
D.	None of the above
Answer» D. None of the above

Discussion

21.	A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is%!
A.	16
B.	15
C.	8
D.	1
Answer» C. 8

Discussion

22.	The frequency range of 300 kHz to 3000 kHz is known as%!
A.	Low frequency
B.	Medium frequency
C.	High frequency
D.	Very high frequency
Answer» C. High frequency

Discussion

23.	In practical commercial FM system, channel bandwidth is%!
A.	150 kHz
B.	100 kHz
C.	88 MHz
D.	108 MHz
Answer» B. 100 kHz

Discussion

24.	*$_A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is?
A.	16
B.	15
C.	8
D.	1
Answer» C. 8

Discussion

25.	*$_In a FM receiver, amplitude limiter?
A.	Amplifiers low frequency signals
B.	Reduces the amplitude of signals
C.	Eliminates any change in amplitude of received FM signals
D.	None of the above
Answer» D. None of the above

Discussion

26.	/_A modem is classified as low speed if data rate handled is?
A.	Upto 100 bps
B.	Upto 250 bps
C.	Upto 400 bps
D.	Upto 600 bps
Answer» E.

Discussion

27.	/_For attenuation of high frequencies we should use?
A.	Shunt capacitance
B.	Series capacitance
C.	Inductance
D.	Resistance
Answer» B. Series capacitance

Discussion

28.	/_The frequency range of 300 kHz to 3000 kHz is known as?
A.	Low frequency
B.	Medium frequency
C.	High frequency
D.	Very high frequency
Answer» C. High frequency

Discussion

29.	/_In practical commercial FM system, channel bandwidth is?
A.	150 kHz
B.	100 kHz
C.	88 MHz
D.	108 MHz
Answer» B. 100 kHz

Discussion

30.	/_The maximum power output of a standard A earth station over the total band allocated to satellite communication is about?
A.	0.5 kW
B.	8 kW
C.	20 kW
D.	50 kW
Answer» B. 8 kW

Discussion

31.	/_In a TV receiver antenna the length of reflector rod?
A.	Is the same as that of dipole
B.	Is less than that of dipole
C.	Is more than that of dipole
D.	May be equal, more or less than that of dipole
Answer» D. May be equal, more or less than that of dipole

Discussion

32.	/_For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as?
A.	2E
B.	3E
C.	4E
D.	6E
Answer» D. 6E

Discussion

33.	/_As per Shannon-Hartley theorem, a noise less Gaussian channel has?
A.	Zero capacity
B.	Infinite capacity
C.	Small capacity
D.	None of the above
Answer» C. Small capacity

Discussion

34.	/_In Modulation, ‚Äö√Ñ√∫carrier‚Äö√Ñ√π is?
A.	Resultant wave
B.	Speech voltage to be transmitted
C.	Voltage with constant frequency, phase or amplitude
D.	Voltage for which frequency, phase or amplitude is varied
Answer» E.

Discussion

35.	/_For AM receivers the standard IF frequency is?
A.	106 kHz
B.	455 kHz
C.	1.07 MHz
D.	10.7 MHz
Answer» C. 1.07 MHz

Discussion

36.	/_If output power of a radio receiver is doubled, its volume is increased by __________ dB.?
A.	2
B.	3
C.	1
D.	-3
Answer» C. 1

Discussion

37.	/_The modulation index of an FM is changed from 0 to 1. How does the transmitted power change??
A.	Gets halved
B.	Gets doubled
C.	Gets increased by 50 percent
D.	Remains unchanged
Answer» D. Remains unchanged

Discussion

38.	/_Which of the following does not cause losses in optical fibre cables??
A.	Stepped index operation
B.	Impurities
C.	Microbending
D.	Attenuation in glass
Answer» B. Impurities

Discussion

39.	/_A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be?
A.	Correlated
B.	Statistically independent
C.	Uncorrelated
D.	Orthogonal
Answer» C. Uncorrelated

Discussion

40.	/_In EM waves, polarization?
A.	Is always vertical in an isotropic medium
B.	Is caused by reflection
C.	Is due to transverse nature of waves
D.	Results from longitudinal nature of waves
Answer» D. Results from longitudinal nature of waves

Discussion

41.	/_Which of the following is an indirect way of generating FM??
A.	Armstrong modulator
B.	Varactor diode modulator
C.	Reactance FET modulator
D.	Reactance bipolar transistor
Answer» B. Varactor diode modulator

Discussion

42.	%_A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be_%
A.	Correlated
B.	Statistically independent
C.	Uncorrelated
D.	Orthogonal
Answer» C. Uncorrelated

Discussion

43.	%_Which of the following does not cause losses in optical fibre cables?_%
A.	Stepped index operation
B.	Impurities
C.	Microbending
D.	Attenuation in glass
Answer» B. Impurities

Discussion

44.	_ For AM receivers the standard IF frequency is$?
A.	106 kHz
B.	455 kHz
C.	1.07 MHz
D.	10.7 MHz
Answer» C. 1.07 MHz

Discussion

45.	_ If output power of a radio receiver is doubled, its volume is increased by __________ dB.$?
A.	2
B.	3
C.	1
D.	-3
Answer» C. 1

Discussion

46.	_ In EM waves, polarization$?
A.	Is always vertical in an isotropic medium
B.	Is caused by reflection
C.	Is due to transverse nature of waves
D.	Results from longitudinal nature of waves
Answer» D. Results from longitudinal nature of waves

Discussion

47.	_ Which of the following is an indirect way of generating FM?$?
A.	Armstrong modulator
B.	Varactor diode modulator
C.	Reactance FET modulator
D.	Reactance bipolar transistor
Answer» B. Varactor diode modulator

Discussion

48.	_ The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?$?
A.	Gets halved
B.	Gets doubled
C.	Gets increased by 50 percent
D.	Remains unchanged
Answer» D. Remains unchanged

Discussion

49.	_ As per Shannon-Hartley theorem, a noise less Gaussian channel has$?
A.	Zero capacity
B.	Infinite capacity
C.	Small capacity
D.	None of the above
Answer» C. Small capacity

Discussion

50.	_ In Modulation, ‚Äö√Ñ√∫carrier‚Äö√Ñ√π is$?
A.	Resultant wave
B.	Speech voltage to be transmitted
C.	Voltage with constant frequency, phase or amplitude
D.	Voltage for which frequency, phase or amplitude is varied
Answer» E.

Discussion

Explore topic-wise MCQs in Electrical Engineering.

An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.%!

Commercial Frequency deviation of FM is%!

In case of low level amplitude modulation system, the amplifiers following the modulated stage must be%!

For a low level AM system, the amplifiers modulated stage must be%!

The colour of an object is decided by%!

What is the purpose of peak clipper circuits in radio transmitters?%!

Full duplex operation permits transmission in both directions at the same time.%!

SSB can be generated by%!

In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then%!

A buffer amplifier is%!

The main function of a balanced modulator is to%!

It is found that a ship to ship communication suffers from fading. This can be avoided by using%!

For telegraphy the most commonly used modulation system is%!

Skip distance depends on time of day and angle of incidence.%!

In a TV receiver antenna the length of reflector rod%!

For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as%!

A modem is classified as low speed if data rate handled is%!

For attenuation of high frequencies we should use%!

The maximum power output of a standard A earth station over the total band allocated to satellite communication is about%!

In a FM receiver, amplitude limiter%!

A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is%!

The frequency range of 300 kHz to 3000 kHz is known as%!

In practical commercial FM system, channel bandwidth is%!

*$_A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is?

*$_In a FM receiver, amplitude limiter?

*/*_A modem is classified as low speed if data rate handled is?

*/*_For attenuation of high frequencies we should use?

*/*_The frequency range of 300 kHz to 3000 kHz is known as?

*/*_In practical commercial FM system, channel bandwidth is?

*/*_The maximum power output of a standard A earth station over the total band allocated to satellite communication is about?

*/*_In a TV receiver antenna the length of reflector rod?

*/*_For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as?

*/*_As per Shannon-Hartley theorem, a noise less Gaussian channel has?

*/*_In Modulation, ‚Äö√Ñ√∫carrier‚Äö√Ñ√π is?

*/*_For AM receivers the standard IF frequency is?

*/*_If output power of a radio receiver is doubled, its volume is increased by __________ dB.?

*/*_The modulation index of an FM is changed from 0 to 1. How does the transmitted power change??

*/*_Which of the following does not cause losses in optical fibre cables??

*/*_A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be?

*/*_In EM waves, polarization?

*/*_Which of the following is an indirect way of generating FM??

%_A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be_%

%_Which of the following does not cause losses in optical fibre cables?_%

_ For AM receivers the standard IF frequency is$?

_ If output power of a radio receiver is doubled, its volume is increased by __________ dB.$?

_ In EM waves, polarization$?

_ Which of the following is an indirect way of generating FM?$?

_ The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?$?

_ As per Shannon-Hartley theorem, a noise less Gaussian channel has$?

_ In Modulation, ‚Äö√Ñ√∫carrier‚Äö√Ñ√π is$?

/_A modem is classified as low speed if data rate handled is?

/_For attenuation of high frequencies we should use?

/_The frequency range of 300 kHz to 3000 kHz is known as?

/_In practical commercial FM system, channel bandwidth is?

/_The maximum power output of a standard A earth station over the total band allocated to satellite communication is about?

/_In a TV receiver antenna the length of reflector rod?

/_For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as?

/_As per Shannon-Hartley theorem, a noise less Gaussian channel has?

/_In Modulation, ‚Äö√Ñ√∫carrier‚Äö√Ñ√π is?

/_For AM receivers the standard IF frequency is?

/_If output power of a radio receiver is doubled, its volume is increased by __________ dB.?

/_The modulation index of an FM is changed from 0 to 1. How does the transmitted power change??

/_Which of the following does not cause losses in optical fibre cables??

/_A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be?

/_In EM waves, polarization?

/_Which of the following is an indirect way of generating FM??