1.The bandwidth in _____ 1.The bandwidth in _____ depends on the number of depends on the number of significant sidebands. significant sidebands. a) FCM a) FCM b) QAM b) QAM c) Delta Modulation c) Delta Modulation d) Frequency Modulation d) Frequency Modulation 2.What is the ratio of 2.What is the ratio of maximum deviation allowed maximum deviation allowed to the modulating frequency to the modulating frequency being used called?
being used called? a) Percent Modulation a) Percent Modulation b) Modulation Index b) Modulation Index c) Modulation Sideband c) Modulation Sideband d) Deviation ratio d) Deviation ratio 3.(Nov 1997) In the 3.(Nov 1997) In the designation of bandwidth and designation of bandwidth and emission, what letter in the emission, what letter in the symbol represents a symbol represents a double-sideband of modulation? a) C sideband of modulation? a) C b) A b) A c) B c) B d) H d) H
4.What is the main function of 4.What is the main function of a balanced modulator?
a balanced modulator?
a) Produce balanced a) Produce balanced modulation of a carrier wave modulation of a carrier wave b) Limit noise picked by a b) Limit noise picked by a receiver
receiver
c) Produce 100% modulation c) Produce 100% modulation d
d) Suppress carrier signal) Suppress carrier signal in order to create a SSB or in order to create a SSB or DSB
DSB
5.What is the major 5.What is the major advantage of FM over AM? advantage of FM over AM? a) Less noise a) Less noise b) Simple circuits b) Simple circuits c) No interference c) No interference d) High frequency d) High frequency
6.A method of generating 6.A method of generating SSB signal; that utilizes only SSB signal; that utilizes only one balanced modulator one balanced modulator circuit. circuit. a) Phase-Shift method a) Phase-Shift method b) Weaver method b) Weaver method c) Third method c) Third method d) Filter method d) Filter method
7.A carrier wave is amplitude
7.A carrier wave is amplitude
modulated by two sine waves
modulated by two sine waves
of different frequencies with
of different frequencies with
modulation indices of 0.3 and
modulation indices of 0.3 and
0.4. What is the overall
0.4. What is the overall
modulation index? modulation index? a) 0.1 a) 0.1 b) 0.5 b) 0.5 c) 0.2 c) 0.2 d) 0.7 d) 0.7 8.For _____ percent 8.For _____ percent modulation in AM, the modulation in AM, the modulation envelope has a modulation envelope has a peak value double the peak value double the unmodulated carrier level. unmodulated carrier level. a) 66.67 a) 66.67 b) 50 b) 50 c) 100 c) 100 d) 83.3 d) 83.3
9.In AM, maximum desirable 9.In AM, maximum desirable output of a transmitter is output of a transmitter is obtained when its modulation obtained when its modulation is _____%. is _____%. a) less than 100 a) less than 100 b) 100 b) 100 c) 50 c) 50 d) greater than 100 d) greater than 100 10.What pattern of 10.What pattern of modulation must used when modulation must used when neutralizing an operating neutralizing an operating transmitter? transmitter? a) 50% a) 50% b) 10 % b) 10 % c) 80% c) 80% d) 100% or over d) 100% or over
11.The PM signal produces 11.The PM signal produces by an FM circuit is called by an FM circuit is called a) Direct PM a) Direct PM b) Indirect FM b) Indirect FM c) Direct FM c) Direct FM d) Indirect PM d) Indirect PM
12.(Nov 1998) What is meant 12.(Nov 1998) What is meant by the term deviation ratio? by the term deviation ratio?
a) The ratio of the audio a) The ratio of the audio modulating frequency to the modulating frequency to the center carrier frequency center carrier frequency b) The ratio of the b) The ratio of the maximum carrier frequency maximum carrier frequency deviation to the highest deviation to the highest audio modulation audio modulation frequency
frequency
c) The ratio of the highest c) The ratio of the highest audio modulating frequency audio modulating frequency to the average audio to the average audio modulating frequency
modulating frequency
d) The ratio of the carrier d) The ratio of the carrier center frequency to the audio center frequency to the audio modulating frequency
modulating frequency
13.What is an application for 13.What is an application for vestigial sideband vestigial sideband transmission? transmission? a) TV Broadcast a) TV Broadcast b) Telephony b) Telephony c) AM Broadcast c) AM Broadcast d) FDM d) FDM
14.The modulation index of 14.The modulation index of an AM wave is changes from an AM wave is changes from 0 to 1. The transmitter power 0 to 1. The transmitter power is? is? a) Increased by 50% a) Increased by 50% b) Doubled b) Doubled c) Unchanged c) Unchanged d) Halved d) Halved
15.What is the carrier power
15.What is the carrier power
transmitted on a 75-transmitted on a 75-ΩΩ antenna if mf=2 and Vc antenna if mf=2 and Vc (unmodulated) is 2 kVpk? (unmodulated) is 2 kVpk? a) 1.29 kW a) 1.29 kW b) 12.9 kW b) 12.9 kW c) 9 kW c) 9 kW d) 10 kW d) 10 kW
16.A SSB transmitter drives
16.A SSB transmitter drives
121 V peak into a
50-121 V peak into a 50-ΩΩ
antenna. What is the PEP?
antenna. What is the PEP?
a) 292 W a) 292 W b) 121 W b) 121 W c) 73 W c) 73 W d) 146W d) 146W
17.A 1500-kHz carrier and 2 kHz intelligence signal are combined in anon-liner device. What component is present at the output?
a) 1492 kHz b) 1502 kHz
c) all of the above d) 1500 kHz
18.(Mar 1996) What is the difference between phase and frequency modulation? a) Os too great to make two systems compatible
b) Is purely theoretical because they are the same in practice
c) Lies in poorer audio response of phase modulation
d) Lies in the different definitions of the modulation index
19.The modulated carrier power in FM
a) Decreases with modulating signal power
b) All of the above
c) Increases with modulating signal power
d) Is independent of modulating signal power 20.(Apr 1998) How does a SSB transmitter output power normally expressed?
a) Peak power b) Average power
c) In term of peak-to-peak power
d) In term of peak envelope power
21.(Nov 1998) In radio regulation. The first symbol in the designation of radio emission is _____.
a) Type of modulation of the main carrier
b) Bandwidth
22.A 2-kW RF carrier is sinusoidally modulated 100% . Haw much power is in one sideband?
a) 500 W b) 125 W c) 2000 W d) 250 W
23.In what classes are SSB linear amplifiers operated? a) C or D
b) D c) B or C d) A or AB
24.What produces splatter in an AM transmission?
a) overmodulation b) Clipping
c) Flickering d) Harmonics
25.An indirect method of generating FM is
a) Varactor diode modulator b) Reactance transistor modulator
c) Armstrong modulator d) Reactance tube modulator 26.What is the power saving when the carrier is suppressed in a regular AM signal modulated to an index of 100%?
a) 66.7 % b) 16.7% c) 33.3% d) 100%
27.What is the result of overmodulation of an FM emission? a) Higher power b) Excessive bandwidth distortion c) distortion d) Lower frequency
28.Which of the following is not an advantage of FM over AM?
a) Less modulating power is required
b) The transmitted power is mote useful
c) Lower bandwidth is required
d) Better noise immunity is provided
29.What type of device can be used in balanced modulators? a) AF, IF b) RF, IF c) AF, RF d) AF, PF
30.An AM signal displayed on an oscilloscope has a maximum span of 5 V and a minimum of 1 V. What is the modulation index? a) 67% b) 120%
c) 20% d) 80%
31.(Nov 1997) Operating method in which the transmission is made alternately in each direction of a telecommunication channel.
a) Simplex operation b) Semi-duplex operation c) Duplex operation
d) Half duplex operation 32.What is the main problem in receiving a suppressed carrier transmission or a single sideband transmission?
a) The gain of the amplifier must be high
b) The selectivity of the receiver must be good.
c) There must be three detectors.
33.(Mar 1996) If the percentage of modulation of an AM amplifier is 88% and the modulation signal is 1 volt, the carrier has an amplitude of _____. a) 0.88 volt b) 1.88 volts c) 1.14 volts d) 0.12 volt 34.In SSB transmission, which sideband can be eliminated?
a) Lower only b) Either c) Upper only
d) Depends upon the use 35.(Apr 1998) A form of single sideband emission where the degree of carrier suppression enables the carrier to be reconstituted and be used for demodulation.
a) Reduced carrier single sideband emission
b) Double sideband emission c) Half carrier single sideband emission
d) Full carrier single sideband emission
36.(Nov 1996) What is the type of emission used by the standard AM radio broadcast? a) D b) F c) C d) A 37.(Apr 1998) If a transmitter supplies 8 kW to the antenna when it is unmodulated, determine the total radiated power when modulated at 30%. a) 5 kW
b) 15 kW c) 8.36 kW d) 20 kW
38.(Nov 1997) Modulation in which the modulated wave is always present. a) Log-periodic modulation b) Continues modulation c) Carrier modulation d) Front-end 39.The power in FM _____ as the modulation index increases. a) Increases
b) Fluctuates
c) Remain constant d) Decreases
40.(Apr 1997) Modulation means a) varying of some parameters of a carrier such as its amplitude to transmit information
b) transmit pulse in DC form on a copper wire
c) utilization of a single transmission channels to carry multiple signals
d) varying of information 41.(Nov 1998) Refers to the first symbol in an emission designation with an amplitude modulated main carrier represented by letter A.
a) Double sideband full carrier
b) Independent sideband c) Double sideband
d) Single sideband suppressed carrier
42.A system uses a deviation of 100 kHz and a modulating frequency of 15 kHz. What is the approximate bandwidth? a) 215 kHz
b) 230 kHz c) 115 kHz d) 200 kHz
43.The rms antenna current for an AM transmitter increases by 15% over the unmodulated value when sinusoidal modulation is applied. Find the depth of modulation.
a) 0.6 b) 0.75 c) 0.8 d) .05
44.(Mar 1996) What is the primary advantage of DSBSC in AM?
a) It is simpler to transmit and receive than the standard AM b) No transmitter power is wasted in the carrier
c) All of these
d) Reduce bandwidth over standard AM
45.If a 7-A carrier is modulated 100% by a sinusoidal tone, how much does the antenna current increase? a) 66.7% b) 22.5% c) 33.3% d) 44.8% 46.(Nov 1997) A single sideband emission in which the degree of carrier suppression enables the carrier to be reconstituted and to be used for demodulation.
a) Half carrier single sideband emission
b) Standard single sideband emission
c) Full carrier single band emission
d) Reduce carrier single sideband emission
47.What is the percent modulation of a signal in the FM broadcast band at 92 MHz with 20 kHz frequency deviation? a) 27% b) 72% c) 12% d) 60% 48.FM has a major disadvantage of _____. a) High voltage b) Greater bandwidth c) Low efficiency d) Greater coverage
49.What is another term meaning “downward modulation”?
a) Positive Carrier Shift b) Harmonic Modulation c) Negative Carrier Shift d) Distortion Modulation 50.Which of the following is not an advantage of vestigial sideband transmission?
a) Reduces power requirements
b) Reduces transmission bandwidth
c) Easy to detect the carrier d) Simple receiver circuitry 51.What formula determines sideband power in AM emissions? a) Pc(m2/2) b) Pc(m2/3) c) Pc(m2/4) d) Pc(m2/5) 52.In communications systems, demodulation ______. a) Is opposite of modulation b) Removes sidebands c) Is performed at the transmitting station
d) Rectifies modulated signal
53.Which of the following is not a major difference between FM and AM receivers? a) IF frequency b) AGC c) deemphasis d) Limiter
54.(Nov 1996) Which symbol indicates that only one sideband is transmitted? a) H3E
b) B8E c) A3E d) C3F
55.In AM, increasing the amplitude of the modulating signal, the amount of power in the information part of the transmitted signal is _____ relative to the power used for the carrier.
a) Constant b) Decreased c) Varying d) Increased
56.(Mar 1996) Three audio waves with 100, 200 and 300 volts amplitude respectively, simultaneously modulate a 450 volts carrier. What is the total percent of modulation of the Am wave?
a) 115.5% b) 69% c) 83% d) 50%
57.What is the greatest possible modulation value without distortion?
a) 50% b) 99.9% c) 100% d) 66.67%
58.What is the power saving in J3E system at 100% modulation? a) 66.67% b) 33.3% c) 100% d) 83.3%
59.What happens in standard AM transmission when no modulating signal is being transmitted?
a) There are no sidebands. b) There are two carriers c) There are several sidebands.
d) There is no signal.
60.(Nov 1998) What is the first symbol of radio signal emission having an amplitude modulated main carrier, double sideband? a) C
b) H c) B d) A
61.Compute the modulation index of an FM signal with a carrier swing of 10 kHz when the modulating signal is 5 kHz.
a) 4 b) 1 c) 0.5 d) 2
62.In what type of transmitters is balanced modulators used? a) SSB b) A3E c) F3E d) PM
63.What do you call a heterodyne frequency changer? a) Mixer b) Modulator c) Frequency synthesizer d) Frequency translator
64.(Nov 1997) An AM transmitter is rated 100 W at 100% modulation. How much power is required for the carrier?
a) 100 W b) 33.33 W c) 66.66 W d) 83.33 W
65.What is the major requirement of the oscillators used in an SSB receiver? a) Selectivity
b) Goof feedback c) High frequency d) stability
66.In FM, what determines bandwidth?
a) Modulation phase b) Carrier power c) Carrier frequency d) Modulation index
67.What is the bandwidth of a narrowband FM signal generates by a 2 kHz audio signal a 110-MHz FM carrier? a) 4 kHz b) 1 kHz c) 2 kHz d) 5 kHz 68.(Nov 1998) In modulation technique, which of the following is referred to audible pitch? a) Frequency b) Harmonic c) Width d) Amplitude
69.To what feature of the modulating tone is FM deviation proportional? a) Frequency b) Amplitude c) Harmonics d) Phase
70.In Frequency Modulation ______.
a) The amplitude of the carrier according to the amplitude of the modulating signal
b) The frequency of carrier varies according to the frequency of the modulating signal
c) The frequency of carrier varies according to the amplitude of the modulating signal
d) The frequency of carrier varies according to the phase of the modulating signal 71.In a transmitted AM wave, state where the information is contained? a) Carrier b) Sidebands c) Modulating signal d) Envelope 72.An 88-MHz carrier is modulated by an audio tone that caused a frequency deviation of 15 kHz. What is the carrier swing of this FM signal?
a) 30 kHz b) 60 kHz c) 45 kHz d) 15 kHz
73.A system has 150 kHz of bandwidth available for a 10-kHz modulating signal. What is the approximate deviation? a) 75 kHz
b) 65 kHz c) 70 kHz d) 100 kHz
74.When the modulating frequency is halved, the modulation index is doubled and the modulating voltage remains constant. The type of modulation is a) AM b) PCM c) FM d) PM 75.For an AM signal modulated to a depth of 100% by a pure tone, the power is _____ the power of unmodulated carrier.
a) 3 / 2 times b) less than c) twice as d) Same as
76.(Nov 1998) A third symbol emission which represent television. (0 correct answers) a) F b) A c) D d) C
77.What is the shape of a trapezoidal pattern at 100% modulation? a) Circle b) Square c) Rectangle d) Triangle
78.The total power content of an AM signal is 600 W. What is the percentage modulation if each sideband contains 100 W?
a) 33.3% b) 66.7% c) 100% d) 83.3%
79.Which of the following is an advantage of PM over FM?
a) One amplifier is required b) Requires a simpler transmitter
c) Requires a complex circuitry
d) A need for several modulators
80.The antenna current of an AM transmitter is 6.2 A when unmodulated and rises to 6.7 A when modulated. What is
the %m? a) 42.8% b) 67% c) 57.9% d) 51%
81.(Mar 1996) In the phase shift method, how many circuits must be balanced? a) None of these
b) 4 c) 1 d) 2
82.In a 5-kW AM transmitter high-level modulation is used. What is the value of the audio signal power needed for 100 percent modulation?
a) 5 kW b) 15 kW c) 50 kW d) 2.5 kW
83.(Nov 1997) The third symbol in the designation of radio emission under the IYU rules refers to
a) bandwidth
b) type of information to be transmitted
c) type of modulation of the main carrier
d) nature of
signal(s)modulating the main carrier
84.Which of the following is not a continuous wave modulation?
a) AM b) PM c) PCM d) FM
85.Determine the power saving in percent when the carrier is suppressed in an AM signal modulated to 80%
a) 75.8% b) 100% c) 66.7% d) 80%
86.A radio transmitter is rated as having a frequency accuracy of ±0.2 parts per million. What is the maximum frequency error at 150 MHz? a) ±7.5 Hz
b) ±20 Hz c) ±30 Hz d) ±150 Hz
87.An FM signal with modulation index m is applied to a frequency tripler. The modulation index at the output is _____.
a) 0 b) 3m c) m / 2 d) m
88.For an FM transmitter, the initial carrier frequency is 8 MHz with a frequency deviation of 1 kHz. If the total frequency multiplication of the transmitter is 12, determine the final; frequency deviation.
a) 120 kHz b) 1 kHz c) 12 kHz d) 8 MHz
89.What factor(s) determine the modulation index of an FM signal?
a) Amplitude of the carrier b) c and d are true
c) Frequency deviation
d) Frequency of the modulation signal
90.An AM transmission of 1000 W is fully modulated. Calculate the power transmitted as a SSB signal. a) 1000 W
b) 333 W c) 667 W d) 167 W
91.What will the normal AM receiver detect from an unmodulated RF AC wave? a) Nothing
b) AF signal c) Carrier d) noise
92.The rms antenna current of a radio transmitter is 10 A when unmodulated, rising to 12 A when the carrier is sinusoidally modulated. What is the modulation factor? a) 1
b) 0.83 c) 0.67 d) 0.94
93.(Mar 1996) The letter-number designation B8E is a form of modulation also known as _____. a) Pilot-carrier system b) Lincompex c) Independent sideband emission d) Vestigial sideband transmission
94.For an FM signal in the 88-108-MHz broadcast band with a frequency deviation of 15 kHz, determine the percent modulation. a) 20% b) 60% c) 40% d) 80%
95.What are the le7tter-number designations of carrier and one SB?
a) A3E b) F3E c) H3E d) J3E 96.FM system is superior to AM because
a) It produces more rock music
b) It has wider bandwidth c) It is at VHR band
d) It eliminates most of amplitude variation noise 97.Calculate the modulating frequency that causes an FM signal to have a bandwidth of 50 kHz when its frequency deviation is 15 kHz. a) 50 kHz b) 40 kHz c) 20 kHz d) 10 kHz 98.During 100% modulation, what percentage of the average output power is in the sidebands?
a) 100% b) 16.67% c) 66.67% d) 33.3%
99.The total transmitted power for an AM signal is 1200 W at 100% modulation. What is the power for each sideband? a) 1200 W b) 100 W c) 200 W d) 1000 W 100.(Nov 1997) A good example of a pilot tone system used in commercial frequency modulation stations. a) Frequency modulation b) Stereo multiplexing c) Time division d) FDM
101.The circuit used for producing a double sideband suppressed carrier type of AM signal is called _____.
a) AGC
b) Balances modulator c) Mixer
d) PLL
102.If an FM transmitter has two doublers and one tripler, what is the carrier swing when the oscillator deviates 2 kHz?
a) 24 kHz b) 2 kHz c) 48 kHz d) 36 kHz
103.In FM, what produces the sidebands?
a) Carrier and its harmonics b) RF signal
c) Carrier signal d) Modulating signal
104.In Phase Modulation (PM), the modulation index represents ______.
a) The ratio of the modulation amplifier to the carrier amplitude
b) The maximum phase shift
c) The maximum frequency deviation
d) The total number of sidebands
105.In FM for a given frequency deviation, the modulation index varies _____ with the modulating
frequency.
a) Independently b) Inversely c) Directly d) Equally
106.What is the maximum power output of a CB A3E emission?
a) 4 W b) 10 kW c) 10 W d) 3 kW
107.(Nov 1996) The output of a balanced modulator is _____. a) LSB and USB b) USB c) Carrier d) LSB
108.The purpose of the balances modulator circuits is to eliminate the _____. a) Distortion b) Sidebands c) Noise d) Carrier 109.(Apr 1998) Refers to an emission designation for facsimile.
a) A3C and F3C b) R3E and A3E c) J3E and F4E d) A3J and A4E
110.Which produces greater interference, overmodulated positive or negative peaks? a) Negative
b) neither c) Positive d) either
111.(Apr 1997) Which transmit only sideband? a) H3E
b) 3AJ c) A3E d) 11BE
112.What is the main feature of DSB transmission? a) Narrow bandwidth b) High reliability c) High voltage d) Carrier is suppressed 113.A 100-V carrier is amplitude modulated by a 1-kHz sine wave. What is the side-frequency amplitude when m=0.75? a) 75 V b) 18.75 V c) 100 V d) 37.5 V 114.An SSB contains 30 kW. The power content of the carrier is _____ kW. a) 30 b) 0 c) 20 d) 10 115.What stage in an AM transmitter creates its own sine wave? a) Buffer b) Modulator c) Oscillator d) Amplifier 116.(Nov 1996) Both frequency and phase modulation utilizes _____ modulation. a) AM and Fm b) Phase c) angle d) Digital
117.The major difference between FM and PM
a) Lies in the poorer audio response of phase modulation index
b) All of the above
c) Lies in the different definition of modulation index d) Is too great to make the two system compatible
118.(Apr 1998) The final power amplifier in an FM y=transmitter usually operates class _____. a) B b) C c) A d) AB
119.What percent of the radiated power is in the sidebands with 50% sinusoidal modulation (AM)? a) 16.67%
b) 33% c) 11% d) 20%
120.What determine the bandwidth of a transmitted AM signal?
a) The lowest modulation amplitude
b) The highest frequency component of the modulating signal
c) The lowest frequency component of the intelligence d) The maximum modulation amplitude
121.(Nov 1998) The third symbol radio emission which represent telephone transmission including sound broadcasting.
a) F b) C c) E d) W
122.What is the letter-number designation for an FM facsimile? a) F3C
b) A3E c) C3C d) F3E
123.An unmodulated carrier is 300 VP-P. Calculate %m when its maximum p-p value reaches 400 V.
a) 100% b) 33.3% c) 66.67% d) 83.3%
124.What is the percent modulation of an AM wave that has a power content of 12 kW in each sideband when modulated by a single tone?
a) 30% b) 66% c) 82% d) 75%
125.(Nov 1997) The first symbol in the designation of radio emission under the ITU rules refers to
a) bandwidth
b) type of modulation of the main carrier
c) nature of signal(s) modulating the main carrier d) type of information to be transmitted
126.What constitutes the input to an AM transmitter? a) Mixer and amplifier b) Mixer and local oscillator c) Buffer and IF amplifier d) RF oscillator and/or audio amplifier
127.When a carrier is frequency-modulated, what is developed on both sides carrier?
128.If the 500-Hz modulation of a 1-MHz carrier has 3rd harmonic distortion, what is the emission bandwidth? a) 3 kHz
b) 1 kHz c) 1500 Hz d) 1 MHz
129.(Apr 1997) 100% modulation inn AM means a corresponding increase in total power by _____. a) 50% b) 100% c) 25% d) 75%
130.A modulation technique commonly used for low-cost digitization of voice signals. a) A3 b) F3 c) A5C d) A0 131.For a 75-MHz FM carrier modulated by 5-kHZ audio tone that causes a frequency deviation of 15 kHz, determine the FM signal bandwidth.
a) 200 kHz b) 100 kHz c) 80 kHz d) 40 kHz
132.(Mar 1996) In AM, the carrier carries _____ intelligence. a) No b) Distorted c) Same d) Difference 133.(Nov 1998) In amplitude modulation technique the unmodulated carrier is referred as having _____. a) 50% modulated b) over modulated c) 0% modulation d) 100% modulation
134.Modulating two waves of the same frequency but with _____. a) 90° b) 180° c) 45° d) 360° 135.For an unmodulated carrier of 1000V and a modulated peak value of 1800 V, what is the modulation index? a) 0.7 b) 0.8 c) 0.9 d) 0.5
136.What factor determines the modulation index of an FM transmission? a) Carrier frequency b) Carrier phase c) Modulating signal frequency d) Carrier amplitude
137.(Mar 1996) Which of the following pulse modulation systems is analog? a) PCM b) Differential PCM c) Delta d) PWM 138.With _____, the modulation envelope is an expression of the amplitude and frequency of the modulation signal. a) AM b) FM c) PCM d) PM 139.(Apr 1998) What is emission C3F? a) Television b) Facsimile c) RTTY d) Modulated CW
140.An FM signal has a frequency deviation of 2000 Hz caused by modulating signal of 500 Hz. What is the modulation index?
a) 2 b) 8 c) 5 d) 4
141.(Apr 1998) Which of the following refers to a double side band full carrier?
a) A3E b) A3J c) F3 d) R3A
142.What is the maximum power that can be contained in the sideband without distortion?
a) 50% b) 25% c) 66.67% d) 16.67%
143.What is the amount of carrier swing necessary to produce an 80% modulation for the audio portion of the TV band?
a) 20 kHz b) 25 kHz c) 50 kHz d) 40 kHz
144.A DSB-SC system must suppress the carrier by 50 dB from its original value of 10 W. To what value must the carrier be reduced?
a) 0.1 W b) 0.001 W c) 0.0001 W d) 0.01W
145.What is the following is not a product of overmodulation? a) Image b) Spurious signal c) Buckshot d) Splatter
146.(Nov 1996) Which determines the number of sideband components in FM? a) Modulation frequency b) Modulation index c) Carrier frequency d) All of these 147.For an FM signal
a) The total number of sidebands depends on the modulation frequency the carrier frequency
b) The carrier frequency cannot disappear
c) The carrier frequency disappears when the modulation index is large d) The amplitude of any sideband depends on the modulation index
