Directions: The item consists of two statements, one labelled as the ‘Assertion (A)’ and the other as ‘Reason (R)’.You are to examine these two statements carefully and select the answers to the item using the codes given below:Assertion (A): In amplitude modulation systems the value of modulation index should be around 1.Reason (R): The power carried in the intelligence carrying sidebands increases with the modulation index.

Both A and R are individually true but R is not the correct explanation of A

Both A and R individually true and R is the correct explanation of A

Both A and R are individually true but R is not the correct explanation of A

In TV transmission, picture signal is amplitude modulated and sound signal is frequency modulated. This is done because:

Sound signal is more susceptible to noise than picture signal

It is not possible to frequency modulate the picture signal

Band width requirement is minimized

Sound signal is more susceptible to noise than picture signal

Synchronization of picture frames becomes easier

In the phase shift SSB method to get upper side band

make two LSBs 180° out of phase

reduce the effect of noise pulses

Consider the signal \({\rm{s}}\left( {\rm{t}} \right) = {\rm{m}}\left( {\rm{t}} \right)\cos \left( {2{\rm{\pi }}{{\rm{f}}_{\rm{c}}}{\rm{t}}} \right) + {\rm{\hat m}}\left( {\rm{t}} \right)sin\left( {2{\rm{\pi }}{{\rm{f}}_{\rm{c}}}{\rm{t}}} \right){\rm{\;}}\)where \({\rm{\hat m}}\left( {\rm{t}} \right)\) denotes the Hilbert transform of \({\rm{m}}\left( {\rm{t}} \right)\) and the bandwidth of \({\rm{m}}\left( {\rm{t}} \right)\) is very small compared to \({{\rm{f}}_{\rm{c}}}\). The signal \({\rm{s}}\left( {\rm{t}} \right)\) is a

double side-band suppressed carrier signal

Directions: It consists of two statements, one labelled as the ‘Statement (I)’ and the other as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below:Statement (I): In AM system the modulation index (0 < m < 1) should be high.Statement (II): The higher the value of m the greater is the power in the side bands.

Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)

Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)

Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)

Statement (I) is true but Statement (II) is false

Statement (I) is false but Statement (II) is true

Match the two lists and choose the correct answer from the code given below:List IList II(a) FM(i) Phase discrimination(b) VSB(ii) Balanced modulator(c) SSB(iii) Chopper type(d) DSB(iv) Phase cancellation method

(a) – (iii), (b) – (i), (c) – (iv), (d) – (ii)

(a) – (iv), (b) – (i), (c) – (iii), (d) – (ii)

(a) – (iv), (b) – (iii), (c) – (i), (d) – (ii)

(a) – (i), (b) – (iii), (c) – (ii), (d) – (iv)

(a) – (iii), (b) – (i), (c) – (iv), (d) – (ii)

Direction: The following item consists of two statements, one labelled as ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answers to these items using the code given below:Statement (I): Modulation index of AM is always kept less than 1.Statement (II): Modulation index for FM may be greater than 1.

Statement I is true but Statement II is false

Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I

Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I

Statement I is true but Statement II is false

Statement I is false but Statement II is true

FM for picture and AM for sound are employed

AM for picture and FM for sound are employed

FM for picture and AM for sound are employed

FM is employed for both picture and sound

AM is employed for both picture and sound

An output of balanced modulator contains

Modulation frequency, carrier frequency, and LSB

Modulation frequency, carrier frequency, and USB

Modulation frequency, LSB and USB

Directions: The question consists of two statements, one labeled as ‘Statement (I)’ and the other labeled as ‘Statement (II)’. You are to examine these two statements carefully and select the answers to these items using the codes given below:Statement (I): PAM can be demodulate using a suitable integrator.Statement (II): A suitable integrator practically acts as an envelope detector.

Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I

Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I

Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I

Statement I is true but Statement II is false

Statement I is false but Statement II is true

An amplitude modulated signal is plotted belowWhich one of the following best describes the above signal?

[9 + sin (4π × 104 t)] sin (5π × 105 t) V

[1 + 9 sin (2π × 104 t)] sin (2.5π × 105 t) V

[9 + sin (2π × 104 t)] sin (2.5π × 105 t) V

[9 + sin (4π × 104 t)] sin (5π × 105 t) V

[9 + sin (2.5π × 105 t)] sin (2π × 104t) V

Directions: It consists of two statements, one labelled as the ‘Statement (I)’ and the other as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below:Statement (I): The total power in the original carrier signal is redistributed between all the components of the spectrum of the frequency-modulated signal.Statement (II): The amplitude of the carrier and the FM signal remain unchanged.

Statement (I) is true but Statement (II) is false

Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)

Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)

Statement (I) is true but Statement (II) is false

Statement (I) is false but Statement (II) is true

In this circuit, Vout is:

Both Upper and Lower Sideband (ωL ± ωm)

A scheme in which several channels are interleaved and then transmitted together is known as

Frequency division multiplexing

83 + Mcqs in Amplitude Modulation in Electronic Devices Circuits Page 1 McqOptions

1.	FM broadcasting service uses the range of frequency bands between
A.	54 - 75 MHz
B.	76 - 87 MHz
C.	88 - 108 MHz
D.	109 - 139 MHz
Answer» D. 109 - 139 MHz

Discussion

2.	If a 400-watt carrier is amplitude modulated to a depth of 75 percent, what is the total power in the modulated wave?
A.	517.5 W
B.	463.3 W
C.	448.5 W
D.	512.5 W
Answer» E.

Discussion

3.	Let c(t) = Ac cos (2πfct) and m(t) = cos (2πfmt). It is given that fc 5fm. The signal c(t) + m(t) is applied to the input of a non-linear device, whose output vo(t) is related to the input vi(t) as v0(t) = avi(t) + bvi2(t) where a and b are positive constants. The output of the non-linear device is passed through an ideal band-pass filter with center frequency fc and bandwidth 3 fm, to produce an amplitude modulated (AM) wave. If it is desired to have the side band power of the AM wave to be half of the carrier power, then a/b is
A.	0.25
B.	0.5
C.	1
D.	2
Answer» E.

Discussion

4.	A bandwidth of 10 kHz is required for AM system. If the lowest frequency component in the modulated signal is 555 kHz, carrier frequency in kHz is:
A.	525
B.	550
C.	560
D.	565
Answer» D. 565

Discussion

5.	For the modulated signal x(t) = m(t) cos (2πfct), the message signal m(t) = 4 cos (1000πt) and the carrier frequency fc is 1 MHz. The signal x(t) is passed through a demodulator, as shown in the figure below. The output y(t) of the demodulator is
A.	cos(460πt)
B.	cos(920πt)
C.	cos(1000πt)
D.	cos(540πt)
Answer» C. cos(1000πt)

Discussion

6.	A transmitter puts out a total power of 2.09 Watts of 30% AM signal. How much power is contained in each of the sidebands?
A.	2.09 watts
B.	2 Watts
C.	0.09 watts
D.	0.045 watts
Answer» E.

Discussion

7.	A 2 kW carrier is to be modulated to a 90% level. The total transmitted power would be
A.	2.81 kW
B.	3.62 kW
C.	1.4 kW
D.	None
Answer» B. 3.62 kW

Discussion

8.	If modulation index of an AM wave is changed from 0 to 1, the transmitted power
A.	increases by 50%
B.	increases by 75%
C.	increases by 100%
D.	remains unaffected
Answer» B. increases by 75%

Discussion

9.	If transmitted power = Pt, modulation index = m, carrier power = Pc, then the total transmitted power in a conventional A.M. system, is given as
A.	Pt = 2Pc (1 + m2/2)
B.	Pt = Pc(1 + m2/2)
C.	Pt = 0.5 Pc (1 + m2/2)
D.	Pt = 0.3 Pc (1 + m2/2)
Answer» C. Pt = 0.5 Pc (1 + m2/2)

Discussion

10.	Directions: The item consists of two statements, one labelled as the ‘Assertion (A)’ and the other as ‘Reason (R)’.You are to examine these two statements carefully and select the answers to the item using the codes given below:Assertion (A): In amplitude modulation systems the value of modulation index should be around 1.Reason (R): The power carried in the intelligence carrying sidebands increases with the modulation index.
A.	Both A and R individually true and R is the correct explanation of A
B.	Both A and R are individually true but R is not the correct explanation of A
C.	A is true but R is false
D.	A is false but R is true
Answer» B. Both A and R are individually true but R is not the correct explanation of A

Discussion

11.	If the value of the modulation index is greater than _______, the wave will be an over-modulated wave
A.	0.75
B.	0.1
C.	0.5
D.	1
Answer» E.

Discussion

12.	In TV transmission, picture signal is amplitude modulated and sound signal is frequency modulated. This is done because:
A.	It is not possible to frequency modulate the picture signal
B.	Band width requirement is minimized
C.	Sound signal is more susceptible to noise than picture signal
D.	Synchronization of picture frames becomes easier
Answer» C. Sound signal is more susceptible to noise than picture signal

Discussion

13.	An amplitude modulated signal has a carrier frequency of 10 kHz. The upper sideband is transmitted at 11 kHz. The bandwidth required for the AM signal to transmit is __________
A.	10 kHz
B.	2 kHz
C.	11 kHz
D.	1 kHz
Answer» C. 11 kHz

Discussion

14.	Determine the average % power in each side frequency in case of AM using sinusoidal modulating wave. Given that the percentage modulation = 20%
A.	10%
B.	5%
C.	1%
D.	18%
Answer» D. 18%

Discussion

15.	In a DSB-SC system with 100% modulation, the power saving is
A.	50 %
B.	66 %
C.	75 %
D.	100 %
Answer» C. 75 %

Discussion

16.	In TV transmission, picture signal is ______ modulated.
A.	Frequency
B.	Phase
C.	Amplitude
D.	None of the above
Answer» D. None of the above

Discussion

17.	In the phase shift SSB method to get upper side band
A.	make two LSBs 180° out of phase
B.	make two LSBs in phase
C.	reduce the effect of noise pulses
D.	limit the noise bandwidth.
Answer» B. make two LSBs in phase

Discussion

18.	In an amplitude modulated signal, modulating frequency is 10 kHz and modulation index is 0.6. What should be the best suited RC time constant for the envelop detector?
A.	0.52 msec
B.	0.02 msec
C.	0.20 msec
D.	0.35 msec
Answer» C. 0.20 msec

Discussion

19.	Consider the signal \({\rm{s}}\left( {\rm{t}} \right) = {\rm{m}}\left( {\rm{t}} \right)\cos \left( {2{\rm{\pi }}{{\rm{f}}_{\rm{c}}}{\rm{t}}} \right) + {\rm{\hat m}}\left( {\rm{t}} \right)sin\left( {2{\rm{\pi }}{{\rm{f}}_{\rm{c}}}{\rm{t}}} \right){\rm{\;}}\)where \({\rm{\hat m}}\left( {\rm{t}} \right)\) denotes the Hilbert transform of \({\rm{m}}\left( {\rm{t}} \right)\) and the bandwidth of \({\rm{m}}\left( {\rm{t}} \right)\) is very small compared to \({{\rm{f}}_{\rm{c}}}\). The signal \({\rm{s}}\left( {\rm{t}} \right)\) is a
A.	high-pass signal
B.	low-pass signal
C.	band-pass signal
D.	double side-band suppressed carrier signal
Answer» D. double side-band suppressed carrier signal

Discussion

20.	An AM wave with modulation index 0.8 has total sideband power of 4.85 kW. The carrier power and the total power radiated will be nearly
A.	12.2 kW and 20 kW
B.	15.2 kW and 20 kW
C.	12.2 kW and 25 kW
D.	15.2 kW and 25 kW
Answer» C. 12.2 kW and 25 kW

Discussion

21.	If a carrier of 100% modulated AM is suppressed before transmission, the power saving is nearly
A.	50 %
B.	67 %
C.	100 %
D.	125 %
Answer» C. 100 %

Discussion

22.	Consider the following statements:i. The lock range of a PLL is the difference between the highest and lowest frequencies that the PLL can remain in lock onto.ii. The capture range of a PLL is the range of frequencies that the voltage controlled oscillator of a PLL can produce.iii. PLL can be used to synchronize the horizontal and vertical oscillators of TV receivers to incoming sync pulses.Which of the above statements is/are correct?
A.	i only
B.	iii only
C.	i and iii only
D.	i, ii and iii
Answer» C. i and iii only

Discussion

23.	A 20 kW carrier is sinusoidally modulated by two carriers corresponding to a modulation index of 20% and 40% respectively. The total radiated power is
A.	22 kW
B.	25 kW
C.	15 kW
D.	17 kW
Answer» B. 25 kW

Discussion

24.	Directions: It consists of two statements, one labelled as the ‘Statement (I)’ and the other as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below:Statement (I): In AM system the modulation index (0 < m < 1) should be high.Statement (II): The higher the value of m the greater is the power in the side bands.
A.	Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
B.	Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)
C.	Statement (I) is true but Statement (II) is false
D.	Statement (I) is false but Statement (II) is true
Answer» B. Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)

Discussion

25.	Match the two lists and choose the correct answer from the code given below:List IList II(a) FM(i) Phase discrimination(b) VSB(ii) Balanced modulator(c) SSB(iii) Chopper type(d) DSB(iv) Phase cancellation method
A.	(a) – (iv), (b) – (i), (c) – (iii), (d) – (ii)
B.	(a) – (iv), (b) – (iii), (c) – (i), (d) – (ii)
C.	(a) – (i), (b) – (iii), (c) – (ii), (d) – (iv)
D.	(a) – (iii), (b) – (i), (c) – (iv), (d) – (ii)
Answer» D. (a) – (iii), (b) – (i), (c) – (iv), (d) – (ii)

Discussion

26.	A DSB-SC signal can be demodulated using:
A.	a synchronous detector
B.	A phase shift discriminator
C.	A low pass filter
D.	An envelope detector
Answer» D. An envelope detector

Discussion

27.	Direction: The following item consists of two statements, one labelled as ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answers to these items using the code given below:Statement (I): Modulation index of AM is always kept less than 1.Statement (II): Modulation index for FM may be greater than 1.
A.	Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I
B.	Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I
C.	Statement I is true but Statement II is false
D.	Statement I is false but Statement II is true
Answer» C. Statement I is true but Statement II is false

Discussion

28.	A 100 V carrier peak changes from 160 V to 40 V by a modulating signal. The modulation factor is
A.	0.3
B.	0.5
C.	0.6
D.	0.7
Answer» D. 0.7

Discussion

29.	In TV transmission
A.	AM for picture and FM for sound are employed
B.	FM for picture and AM for sound are employed
C.	FM is employed for both picture and sound
D.	AM is employed for both picture and sound
Answer» B. FM for picture and AM for sound are employed

Discussion

30.	A DSB-SC signal is generated using the carrier signal cos (ωct + θ) and modulating signal m(t). What is the envelope detector output of this DSB-SC signal?
A.	m(t) cos θ
B.	\|m(t)\|
C.	m(t) tan θ
D.	m(t) sin θ
Answer» C. m(t) tan θ

Discussion

31.	If the modulation index of an AM wave is 0.6, the power saved in SSB compared to AM is
A.	94%
B.	90%
C.	80%
D.	92.37%
Answer» E.

Discussion

32.	An audio signal, 15 sin (2π 1500t) amplitude modulates 60 sin (2π 103t). The modulation index will be:
A.	20%
B.	50%
C.	25%
D.	100%
Answer» D. 100%

Discussion

33.	A 1000 W carrier is amplitude-modulated and has a side-band power of 300 W. The depth of modulation is:
A.	0.255
B.	0.545
C.	0.775
D.	0.95
Answer» D. 0.95

Discussion

34.	If mf is modulation index of FM, What is the value of ratio (S/N)WBFM/(S/N)AM for 100% amplitude modulation with identical total transmitted power?
A.	\(\frac{9}{2} m_f^2\)
B.	\(\frac{3}{2} m_f^2\)
C.	\(\frac{3}{2} m_f^3\)
D.	\(\frac{9}{2} m_f^3\)
Answer» B. \(\frac{3}{2} m_f^2\)

Discussion

35.	A 500-watt carrier is modulated to a depth of 80%. Calculate the total power in the modulated wave.
A.	512.5 W
B.	500 W
C.	450 W
D.	660 W
Answer» E.

Discussion

36.	An amplitude modulated signal is [A + 0.5 A cos ωm t] cos ωc t where ωm and ωc are respectively, modulating and carrier frequencies. The power efficiency is
A.	11.11%
B.	0.25%
C.	4.32%
D.	50%
Answer» B. 0.25%

Discussion

37.	An output of balanced modulator contains
A.	Carrier, LSB, and USB
B.	Modulation frequency, carrier frequency, and LSB
C.	Modulation frequency, carrier frequency, and USB
D.	Modulation frequency, LSB and USB
Answer» E.

Discussion

38.	A VSB transmitter that transmits 25% of the other sideband along with the wanted sideband radiates 0.625 kW when the modulation percentage is 60%. If we want to transmit the same message by an AM transmitter then the carrier power (in kW) required is
A.	6.56 kW
B.	5.56 kW
C.	4.56 kW
D.	7.56 kW
Answer» C. 4.56 kW

Discussion

39.	Directions: The question consists of two statements, one labeled as ‘Statement (I)’ and the other labeled as ‘Statement (II)’. You are to examine these two statements carefully and select the answers to these items using the codes given below:Statement (I): PAM can be demodulate using a suitable integrator.Statement (II): A suitable integrator practically acts as an envelope detector.
A.	Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I
B.	Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I
C.	Statement I is true but Statement II is false
D.	Statement I is false but Statement II is true
Answer» B. Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I

Discussion

40.	A message signal of frequency 100 MHz and peak voltage 100 V is used to execute amplitude modulation on a carrier wave of frequency 300 GHz and peak voltage 400 V. The modulation index and bandwidth are:
A.	4; 1 × 108 Hz
B.	4; 2 × 108 Hz
C.	0.25; 2 × 108 Hz
D.	0.25; 1 × 108 Hz
Answer» D. 0.25; 1 × 108 Hz

Discussion

41.	A modulating signal consists of a symmetrical triangular wave having zero DC component and peak-to-peak voltage of 11 V. It is used to modulate a carrier with the peak voltage of 10 V. Calculate the modulation index.
A.	0.55
B.	0.28
C.	0.14
D.	0.05
Answer» B. 0.28

Discussion

42.	An amplitude modulated signal is plotted belowWhich one of the following best describes the above signal?
A.	[1 + 9 sin (2π × 104 t)] sin (2.5π × 105 t) V
B.	[9 + sin (2π × 104 t)] sin (2.5π × 105 t) V
C.	[9 + sin (4π × 104 t)] sin (5π × 105 t) V
D.	[9 + sin (2.5π × 105 t)] sin (2π × 104t) V
Answer» C. [9 + sin (4π × 104 t)] sin (5π × 105 t) V

Discussion

43.	Directions: It consists of two statements, one labelled as the ‘Statement (I)’ and the other as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below:Statement (I): The total power in the original carrier signal is redistributed between all the components of the spectrum of the frequency-modulated signal.Statement (II): The amplitude of the carrier and the FM signal remain unchanged.
A.	Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
B.	Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)
C.	Statement (I) is true but Statement (II) is false
D.	Statement (I) is false but Statement (II) is true
Answer» C. Statement (I) is true but Statement (II) is false

Discussion

44.	A phase lock loop with a first loop filter can track:
A.	phase offset
B.	frequency offset
C.	frequency offset rate
D.	amplitude variation
Answer» C. frequency offset rate

Discussion

45.	Most commonly used filter in SSB generation are
A.	Mechanical filters
B.	RC filters
C.	LC filters
D.	Low pass filters
Answer» B. RC filters

Discussion

46.	In this circuit, Vout is:
A.	Upper Sideband (ωL + ωm)
B.	Lower Sideband (ωL - ωm)
C.	Both Upper and Lower Sideband (ωL ± ωm)
D.	None of above
Answer» B. Lower Sideband (ωL - ωm)

Discussion

47.	A scheme in which several channels are interleaved and then transmitted together is known as
A.	Frequency division multiplexing
B.	TDM
C.	a group
D.	a super group
Answer» B. TDM

Discussion

48.	An amplitude-modulated amplifier has a radio frequency output of 50 W at 100% modulation. The internal loss in the modulator is 10 W. The unmodulated carrier power is
A.	40 W
B.	50 W
C.	60 W
D.	80 W
Answer» B. 50 W

Discussion

49.	If modulation index is √2, what would be the effective transmitted power?
A.	Equal to carrier power
B.	Half of carrier power
C.	2 times of carrier power
D.	√2 times of carrier power
Answer» D. √2 times of carrier power

Discussion

50.	In a FDM system, 10 channels are multiplexed: Each channel having a BW of 50 kHz. If the guard band between the channels are 1 kHz, the minimum bandwidth required for transmission is(1) 505 kHz(2) 500 kHz(3) 509 kHz(4) 510 kHz
A.	1
B.	2
C.	3
D.	4
Answer» D. 4

Discussion

Explore topic-wise MCQs in Electronic Devices Circuits.

FM broadcasting service uses the range of frequency bands between

If a 400-watt carrier is amplitude modulated to a depth of 75 percent, what is the total power in the modulated wave?

A bandwidth of 10 kHz is required for AM system. If the lowest frequency component in the modulated signal is 555 kHz, carrier frequency in kHz is:

For the modulated signal x(t) = m(t) cos (2πfct), the message signal m(t) = 4 cos (1000πt) and the carrier frequency fc is 1 MHz. The signal x(t) is passed through a demodulator, as shown in the figure below. The output y(t) of the demodulator is

A transmitter puts out a total power of 2.09 Watts of 30% AM signal. How much power is contained in each of the sidebands?

A 2 kW carrier is to be modulated to a 90% level. The total transmitted power would be

If modulation index of an AM wave is changed from 0 to 1, the transmitted power

If transmitted power = Pt, modulation index = m, carrier power = Pc, then the total transmitted power in a conventional A.M. system, is given as

If the value of the modulation index is greater than _______, the wave will be an over-modulated wave

In TV transmission, picture signal is amplitude modulated and sound signal is frequency modulated. This is done because:

An amplitude modulated signal has a carrier frequency of 10 kHz. The upper sideband is transmitted at 11 kHz. The bandwidth required for the AM signal to transmit is __________

Determine the average % power in each side frequency in case of AM using sinusoidal modulating wave. Given that the percentage modulation = 20%

In a DSB-SC system with 100% modulation, the power saving is

In TV transmission, picture signal is ______ modulated.

In the phase shift SSB method to get upper side band

In an amplitude modulated signal, modulating frequency is 10 kHz and modulation index is 0.6. What should be the best suited RC time constant for the envelop detector?

An AM wave with modulation index 0.8 has total sideband power of 4.85 kW. The carrier power and the total power radiated will be nearly

If a carrier of 100% modulated AM is suppressed before transmission, the power saving is nearly

A 20 kW carrier is sinusoidally modulated by two carriers corresponding to a modulation index of 20% and 40% respectively. The total radiated power is

Match the two lists and choose the correct answer from the code given below:List IList II(a) FM(i) Phase discrimination(b) VSB(ii) Balanced modulator(c) SSB(iii) Chopper type(d) DSB(iv) Phase cancellation method

A DSB-SC signal can be demodulated using:

A 100 V carrier peak changes from 160 V to 40 V by a modulating signal. The modulation factor is

In TV transmission

A DSB-SC signal is generated using the carrier signal cos (ωct + θ) and modulating signal m(t). What is the envelope detector output of this DSB-SC signal?

If the modulation index of an AM wave is 0.6, the power saved in SSB compared to AM is

An audio signal, 15 sin (2π 1500t) amplitude modulates 60 sin (2π 103t). The modulation index will be:

A 1000 W carrier is amplitude-modulated and has a side-band power of 300 W. The depth of modulation is:

If mf is modulation index of FM, What is the value of ratio (S/N)WBFM/(S/N)AM for 100% amplitude modulation with identical total transmitted power?

A 500-watt carrier is modulated to a depth of 80%. Calculate the total power in the modulated wave.

An amplitude modulated signal is [A + 0.5 A cos ωm t] cos ωc t where ωm and ωc are respectively, modulating and carrier frequencies. The power efficiency is

An output of balanced modulator contains

A VSB transmitter that transmits 25% of the other sideband along with the wanted sideband radiates 0.625 kW when the modulation percentage is 60%. If we want to transmit the same message by an AM transmitter then the carrier power (in kW) required is

A message signal of frequency 100 MHz and peak voltage 100 V is used to execute amplitude modulation on a carrier wave of frequency 300 GHz and peak voltage 400 V. The modulation index and bandwidth are:

A modulating signal consists of a symmetrical triangular wave having zero DC component and peak-to-peak voltage of 11 V. It is used to modulate a carrier with the peak voltage of 10 V. Calculate the modulation index.

An amplitude modulated signal is plotted belowWhich one of the following best describes the above signal?

A phase lock loop with a first loop filter can track:

Most commonly used filter in SSB generation are

In this circuit, Vout is:

A scheme in which several channels are interleaved and then transmitted together is known as

An amplitude-modulated amplifier has a radio frequency output of 50 W at 100% modulation. The internal loss in the modulator is 10 W. The unmodulated carrier power is

If modulation index is √2, what would be the effective transmitted power?

In a FDM system, 10 channels are multiplexed: Each channel having a BW of 50 kHz. If the guard band between the channels are 1 kHz, the minimum bandwidth required for transmission is(1) 505 kHz(2) 500 kHz(3) 509 kHz(4) 510 kHz