Reviewer
PART 1
(Source: Lesson 4: Amplitude
Modulation)
1.) An antenna transmits an AM signal
having a total power content of 15kW.
Determine the power being transmitted at
each of the sidebands when the percent
modulation is 85%
a. 1101.9 W
b. 1990 W
c. 3981 W
d. 1019 W
2.) In the designation of the bandwidth
and emission, what letter in the first
symbol represents an ISB signal?
a. J
b. B
c. A
d. C
3.) A modulator circuit performs what
mathematical operation on its two
inputs?
a. Addition
b. Multiplication
c. Division
d. subtraction
4.) An AM transmitter is modulated by
two sine waves at 1kHz and 2.5kHz, with
modulations
of
25%
and
50%
respectively. What is the effective
modulation index?
a. 0.56
b. 0.65
c. 0.75
d. 0.25
5.) A 2000 Hz audio signal having
amplitude of 15V amplitude modulates a
100kHz carrier, which has a peak value
of 25V when not modulated. Calculate
the modulation factor of the modulated
wave.
a. 0.4
b. 0.5
c. 0.6
d. 0.7
6.) In the previous problem, what
frequencies would show up in a spectrum
analysis of the AM wave?
a. 98kHz, 100kHz, 102kHz
b. 90.8kHz, 100kHz, 102.8kHz
c. 98.8kHz, 100kHz, 102.2kHz
d. 198kHz, 200kHz, 202kHz
7.) What is the required bandwidth to
transmit the AM signal in the previous
problem?
a. 2kHz
b. 4kHz
c. 200kHz
Reviewer
d. None of the above
8.) A bandwidth of 12MHz becomes
available for assignment. If assigned for
TV broadcast service, only two channels
could be accommodated. Determine the
number of AM stations that could be
broadcast
simultaneously
if
the
maximum frequency is limited to 5kHz
a. 1000
b. 1200
c. 800
d. 1600
9.) Which is true about over modulation?
a. A modulating voltage is less than
a carrier voltage
b. The modulating voltage is equal to
the carrier voltage
c. Overmodulation
produces
a
distortion at the demodulated
output
d. None of the above
10.) The percentage of the modulation for
a maximum amplitude of information
transmission is ___%
a. 0
b. 50
c. 75
d. 100
PART 2
(Source: Lesson 5: Single-Sideband
Systems)
1.) For an AM DSBFC wave with a peak
unmodulated voltage of 10V and a load
resistance of 10Ω, the given modulation
index is 0.5. Determine the following:
a. The carrier and the sideband
power
b. The total power
c. The percent power of the
information
d. The power spectrum
2.) Calculate the percentage power
saving when the carrier and one of the
sidebands is suppressed in an AM signal
if the modulation index is
a. 100%
b. 25%
3.) For a 500-W carrier modulated to a
depth of 80%, find the total power and the
%P.S in each of the following forms of
AM
a. J3E
b. H3E
c. DSB
4.) An AM wave has a total transmitted
power of 4kW when modulated at 85%.
How much total power should an SSB
wave contain in order to have the same
power as that in the two sidebands?
Reviewer
5.) If a transmitter power of 100W is
sufficient for reliable communication over
a certain path using SSB, approximately
what power would be required using
H3E?
6.) What is the maximum modulating
signal frequency that can be used in a
J3E system with a 50kHz bandwidth?
10.) The CB radio was developed using
a full-carrier DSB AM. It operates using
40 channels, each 10kHz. When the
SSBSC is used, the same carrier
frequencies are used as with the
conventional AM, but the transceivers
are switchable to either a lower or an
upper sideband. How many channels are
available when SSB is used?
80
7.) A filter-type SSB generator uses an
ideal bandpass filter with a center
frequency of 5.000Mhz and a bandwidth
of 2.7kHz. What frequency should be
used for the carrier oscillator if the
generator is to produce an LSB signal
with a baseband frequency response
having a lower limit of 280kHz?
11.) What is the power saving of a double
sideband full carrier AM signal at 50%
modulation, if the emission used is J3E?
12.) What is the maximum modulating
signal frequency that can be used with a
H3E system with a 50kHz bandwidth?
50kHz
8.) An SSBSC signal has a suppressed
carrier frequency of 1500 and 2200Hz.
The receiver is mistuned so that the BFO
is at 1.9995Mhz. What will be the output
frequencies of the demodulator if the
signal is LSB?
13.) An AM transmission 1000W is fully
modulated.
Calculate
the
power
transmitted if it is transmitted as a SSB
signal
14.) A SSB transmission drives a 110Vpk
into a 75Ω antenna. Calculate PEP.
9.) A J3E transmitter operating at 16MHz
has a frequency stability of 1 part per
million. If its transmission is reproduced
by a receiver whose frequency stability is
8 parts per million, what is the maximum
frequency error of the output of this
receiver
in
reproducing
this
transmission?
15.) An SSB transmitter has a PEP
10kW, what is the average power?
Reviewer
16.) An AM wave has a total transmitted
power of 4kW when modulated at 85%.
What is the total transmitted power if J3E
was used instead?
a. 1061.5W
b. 530.76W
c. 2123W
d. 2938.5W
17.) CB radios were developed using the
full-carrier DSB AM. It operated using 40
channels, each 10kHz wide. When
SSBSC is used, the same carrier
frequencies are used as with the
conventional AM but transceivers are
switchable to either lower and upper
sideband. How many channels are
available when the SSB is used?
a. 40
b. 60
c. 80
d. 120
18.) The type of AM signal that is used in
a TV broadcasting is called
a. B8E
b. CF3
c. R3E
d. H3E
19.) Which of the following statements is
not true about single sideband
transmission?
a. SSB transmission saves power
b. It occupies less bandwidth
c. Less complex
d. None of the above
20.) If a transmitter power of 100W is
sufficient for reliable communications
over a certain path using the SSB,
approximately what power level would be
required using the DSB?
a. 300W
b. 600W
c. 100W
d. 200W
21.) If a transmitter power of 1000W is
sufficient for reliable communications
over a certain path using the SSB,
approximately what power level would be
required using the DSB? What is the
power required for a full-carrier AM?
a. 600W
b. 100W
c. 200W
d. 800W
22.) Anticipating single sideband AM,
what percentage of the total power is
saved by suppressing the carrier and one
sideband while transmitting the other
sideband only for m=0.75?
a. 66.7%
b. 89%
c. 100%
d. 45%
23.) If the carrier signal of a 100%
modulated AM wave is suppressed, the
percentage power saving will be
a. 50
b. 150
c. 100
d. 66.66
24.) One of the following cannot be used
to remove the unwanted sideband in
SSB. This is the
a. Filter system
b. Phase-shift method
c. Detector
d. Weaver method
25.) To provide two or more voice circuits
with the same carrier, it is necessary to
use the
a. ISB
b. Carrier insertion
c. SSB with a pilot carrier
d. Lincompex
Reviewer
PART 3
(Source: MCQ Phase Modulation
Question & Answers)
1. Phase modulation is a type of
modulation used for the ______ of
communicating signals.
a. Reception
b. Transmission
c. Hybrid
d. None of these
2. Phase modulation has ___ forms of
modulation.
e. 2
f. 3
g. 7
h. 9
3. Input signal in phase modulation
changes according to ___ of a carrier
wave.
i. Amplitude
j. Phase
k. Frequency
l. Time
4.
h
in
phase
modulation
represents______?
m. Modulation Index
n. Frequency
o. Amplitude
p. Carrier Wave
5.
Modulation
index(h)
formula=_______?
q. Δf
r. Δm
s. Δθ
t. Δg
6. If height of the signals are short, then
Phase modulation behaves similar to
_____?
u. Frequency Modulation
v. Amplitude Modulation
w. Phase Modulation
x. None of these
7. For a high sine wave, Phase
modulation behaves the same as
_______?
y. Frequency Modulation
z. Amplitude Modulation
aa. Phase Modulation
h. None of these
8. Δθ represents _______?
a. High peak
b. Peak Phase Deviation
c. Sine Wave
d. Swing
9. Phase modulation is extensively
used in transmitting _____ waves.
a. Infrared
b. Ultra
c. Radio
d. X-ray
10. Carson rule formula represented
by _______?
a. 2(h+1)fm
b. 2fm
c. 2hfm
d. None Of These
11. Message
signal
in
phase
modulation is represented by
_____?
a. w(t)
b. m(t)
c. p(t)
d. q(t)
12. Phase modulation is used in
technologies like ___?
a. Wi-fi
b. Edge
c. Ethernet
d. Wired
13. Phase modulation is also used in
_____?
a. Modulars
b. Digital synthesizers
c. Amplifiers
d. Actuators
14. Carrier
signal
formula
in
modulation are ______?
a. Acsin(ctc)
b. Amsin(ct+c)
c. Acsin(ct+c)
d. Acsin(ct+c+1)
15. Message
signal
m(t)
is
represented by ______?
a. cos(cthm(t))
b. cos(ct+hm(t))
c. cos(ct+hm(t)+1)
d. cos(cthm(t)+1)
16. Phase modulation is also called
______ modulation?
a. Di Amplitude
b. Quadrature amplitude
c. Double amp
d. Hecta amplifier
17. Frequency
modulation
will
change to phase modulation by
Reviewer
appending ____ network to the
message signal.
a. LR
b. CR
c. RCL
d. LC
18. _____ phase modulation is most
widely used.
a. Analog
b. Digital
c. Hybrid
d. None of these
19. Ac in the equation is defined as
carrier signal ____?
a. Amplitude
b. Phase
c. Frequency
d. Time
20. c in the equation is defined as
carrier signal ______?
a. Wavelength
b. Amplitude
c. Frequency
d. Angular frequency
21. Movement of complete negative
and _____ phases form a
complete sine wave.
a. Positive
b. Negative
c. Null
d. None of these
22. Phase is _____ proportional to
time.
a. Indirectly
b. Directly
c. Hybrid
d. Continuous
23. For phase modulation _____ be
placed in the middle of AM and
FM.
a. Wavelength
b. Noise immunity
c. Bandwidth
d. Frequency variations
24. Noise exemption is less in phase
modulation than _____?
a. AM
b. PWM
c. FM
d. DM
25. In PM, the Signal to Noise ratio is
not _____ than FM.
a. Worst
b. Superior
c. Least
d. Quality
26. _____ services are mostly used
in phase modulation?
a. Frequency
b. Phase
c. Mobile Radio
d. None Of These
27. Noise immunity is ____ in PM,
than that of AM.
a. Low
b. Least
c. More
d. Null
28. Even if we increase the quality of
frequency deviation, the noise
immunity can’t increase in ___?
a. AM
b. PM
c. PWM
d. FM
29. The whole power will make use of
___ modulators?
a. AM
b. PM
c. PWM
d. FM
30. Bandwidth in PM depends on
_______?
a. Wavelength
b. Time
c. Modulation Index
d. Frequency deviation
31. Bandwidth is high in ___ than AM
and FM.
a. FM
b. PWM
c. PM
d. AM
32. Receivers and transmitters are
____ to design in PM?
a. Easy
b. Complex
c. Trouble-Free
d. Effortless
33. Expand PSK _______?
a. Plant shift keying
b. Phase shift keying
c. Phase sine key
d. None of these
34. Expand BPSK _____?
a. Binary phase-shift keying
b. Binary plane size keying
c. Binary phase sine keying
Reviewer
d. None of these
35. Expand QPSK full form_______?
a. Quadrature
phase-shift
keying
b. Quartz plane sine keying
c. Quad phase sine keying
d. None of these
36. Phase modulation exists with
_____ speed of communication?
a. Low
b. High
c. Least
d. Null
37. Exceeds phase range up to ____
due to uncertainty in PM?
a. 270
b. 180
c. 90
d. 360
38. Modulation index enlarges by
adding _____ component.
a. Shift Registers
b. Frequency Multipliers
c. Amplifiers
d. Oscillators
39. ______ exists between two points
of a circle in PM.
a. Frequency deviation
b. Phase Angle
c. Angular Frequency
d. Modulators
40. Units
of
phase
sensitivity
______?
a. rad/amp
b. amp/volts
c. rad/volts
d. 1/volts
41. Phase sensitivity is represented
by _____?
a. Kp x(t)
b. Kv x(t)
c. Kx x(t)
d. None of these
42. Due to sound, combination
______ takes place in PM.
a. Phase Distortion
b. Phase Angle
c. Bandwidth
d. Noise immunity
43. Phase modulation has constant
_____?
a. Frequency
b. Phase
c. Amplitude
d. Angle
44. Phase modulation has ___ quality
receiving signals?
a. High
b. Low
c. Medium
d. Constant
45. In PM, phase is directly
proportional to ______?
a. Amplitude
b. Bandwidth
c. Frequency
d. Phase
46. In PM, amplitude and ______
maintain the same properties.
a. Amplitude
b. Bandwidth
c. Frequency
d. Phase
47. Expand OPSK full form _____?
a. Offset phase shift keying
b. Onboard
phase
shift
keying
c. On phase switch keying
d. None of these
48. Velocity is been identified based
on unattached _____?
a. Doppler Effect
b. Bandwidth
c. Angular Frequency
d. Wireless
49. In phase modulation, the ___
signals are required with phase
variations in them.
a. One
b. Two
c. Three
d. Four
50. ______ reaches if we increase the
phase radian of modulation?
a. Phase Angle
b. Phase Ambiguity
c. Phase Distortion
d. None of these
PART 4:
(Source: MCQ in Modulation Part 18)
1. Having an information signal
change some characteristic of a
carrier signal is called
a. Multiplexing
b. Modulation
Reviewer
2.
3.
4.
5.
6.
7.
8.
9.
c. Duplexing
d. Linear mixing
Which of the following is not true
about AM?
a. The
carrier
amplitude
varies.
b. The
carrier
frequency
remains constant.
c. The
carrier
frequency
changes.
d. The information signal
amplitude changes the
carrier amplitude.
he opposite of modulation is
a. Reverse modulation
b. Downward modulation
c. Unmodulation
d. Demodulation
The circuit used to produce
modulation is called
a. Modulator
b. Demodulator
c. Variable gain amplifier
d. Multiplexer
A modulator circuit performs what
mathematical operation on its two
inputs?
a. Addition
b. Multiplication
c. Division
d. Square root
The ratio of the peak modulating
signal voltage to the peak carrier
voltage is referred to as
a. The voltage ratio
b. Decibels
c. The modulation index
d. The mix factor
If m is greater than 1, what
happens?
a. Normal operation
b. Carrier drops to zero
c. Carrier frequency shifts
d. Information
signal
is
distorted
For ideal AM, which of the
following is true?
a. m = 0
b. m = 1
c. m < 1
d. m > 1
The outline of the peaks of a
carrier has the shape of the
modulating signal and is called the
a. Trace
b. Waveshape
c. Envelope
d. Carrier variation
10. Overmodulation occurs when
a. Vm > Vc
b. Vm < Vc
c. Vm = Vc
d. Vm = Vc = 0
11. The values of Vmax and Vmin as
read from an AM wave on
oscilloscope are 2.8 and 0.3. the
percentage of modulation is
a. 10.7%
b. 41.4%
c. c. 80.6%
d. d. 93.3%
12. The new signals produced by
modulation are called
a. Spurious emissions
b. Harmonics
c. Intermodulation products
d. Sidebands
13. A carrier of 880 kHz is modulated
by a 3.5 kHz sine wave. The LSB
and USB are, respectively,
a. a. 873 and 887 kHz
b. 876.5 and 883.5 kHz
c. c. 883.5 and 876.5 kH
d. d. 887 and 873 kHz
14. A display of signal amplitude
versus frequency is called the
a. Time domain
b. Frequency Spectrum
c. Amplitude Spectrum
d. Frequency Domain
15. Most of the power in an AM signal
is in the
a. Carrier
b. Upper sideband
c. Lower sideband
d. Modulating signal
16. An AM signal has a carrier power
of 5 W. the percentage of
modulation is 80% the total
sideband power is
a. 0.8 W
b. 1.6 W
c. 2.5 W
d. 4.0 W
17. An AM signal has a carrier power
of 5 W. the percentage of
modulation is 80% the total
sideband power is
Reviewer
a.
b.
c.
d.
0.8 W
1.6 W
2.5 W
4.0 W
18. An AM transmitter has a
percentage of modulation of 88.
The carrier power is 440 W. The
power is 440 W. The power in one
sideband is
a. 85 W
b. 110 W
c. 170 W
d. 610 W
19. An AM transmitter antenna
current is measured with no
modulation and found to be 2.6
amperes. With modulation, the
current rises to 2.9 amperes. The
percentage of modulation is
a. 35%
b. 70%
c. 42%
d. 89%
20. What is the carrier power in the
problem above if the antenna
resistance is 75 ohms?
a. 195 W
b. 631 W
c. 507 W
d. 792 W
21. In an AM signal, the transmitted
information is contained within the
a. Carrier
b. Modulating signal
c. Sidebands
d. Envelope
22. An AM signal without the carrier is
called a(n)
a. SSB
b. Vestigial sideband
c. FM signal
d. DSB
23. What is the minimum AM signal
needed to transmit information?
a. Carrier plus sidebands
b. Carrier only
c. One sideband
d. Both sideband
24. The main advantage of SSB over
standard AM or DSB is
a. Less spectrum space is
used
b. Simpler equipment is used
c. Less power is consumed
d. A
higher
modulation
percentage
25. In SSB, which sideband is the
best to use?
a. Upper
b. Lower
c. Neither
d. Depends upon the use
26. The typical audio modulating
frequency range used in radio and
telephone communication is
a. 50 Hz to 5 kHz
b. 50 Hz to 15 kHz
c. 100 Hz to 10kHz
d. 300 Hz to 3 kHz
27. An AM signal with a maximum
modulating signal frequency of 4.5
kHz has a total bandwidth of
a. 4.5 kHz
b. 6.75 kHz
c. 9 kHz
d. 18 kHz
28. The modulation system used for
telegraphy is
a. Frequency-shift keying
b. Two-tone modulation
c. Pulse-code modulation
d. Single-tone modulation
29. The process of translating a
signal, with or without modulation,
to a higher or lower frequency for
processing is called
a. Frequency multiplication
b. Frequency division
c. Frequency shift
d. Frequency conversion
30. Frequency translation is carried
out by a circuit called a
a. Translator
b. Convertor
c. Balanced modulator
d. Local oscillator
31. An input signal of 1.8 MHz is
mixed with a local oscillator of 5
MHz. A filter selects the difference
signal. The output is
a. 1.8 MHz
b. 3.2 MHz
c. 5 MHz
d. 6.8 MHz
32. One
type
of
pulse
communications system uses
pulse that appear as a group, and
which vary in number according to
Reviewer
the loudness of the voice. This
type of pulse modulation is called
a. Pulse duration modulation
b. Pulse
amplitude
modulation
c. Pulse code modulation
d. Pulse position modulation
33. An SSB transmitter produces a
400-V peak to peak signal across
a 52-Ω antenna load. The PEP
output is
a. 192.2 W
b. 384.5 W
c. 769.2 W
d. 3077 W
34. The output power of an SSB
transmitter is usually expressed in
terms of
a. Average power
b. RMS power
c. Peak-to-peak power
d. Peak envelope power
35. The letter-number designation
B8E is a form of modulation also
known as
a. Pilot-carrier system
b. Independent
sideband
emission
c. Lincomlex
d. Vestigial
sideband
transmission
36. Amplitude modulation is the same
as
a. Linear mixing
b. Analog multiplication
c. Signal summation
d. Inductor
37. In a diode modulator, the negative
half of the AM wave is supplied by
a(n)
a. Tuned circuit
b. Transformer
c. Capacitor
d. Inductor
38. Amplitude modulation can be
produced by
a. Having the carrier vary a
resistance
b. Having the modulating
signal vary a capacitance
c. Varying
the
carrier
frequency
d. Varying the gain of an
amplifier
39. Amplitude modulators that vary
the carrier amplitude with the
modulating signal by passing it
through an attenuator work on the
principle of
a. Rectification
b. Resonance
c. Variable resistance
d. Absorption
40. The component used to produce
AM at very high frequencies is a
a. Varactor
b. Thermistor
c. Cavity resonator
d. PIN diode
41. Amplitude modulation generated
at a very low voltage or power
amplitude is known as
a. High-level modulation
b. Low-level modulation
c. Collector modulation
d. Minimum modulation
42. A collector modulator has a
supply voltage of 48 V. The peakto-peak
amplitude
of
the
modulating signal for 100 percent
modulation is
a. 24 V
b. 48 V
c. 96 V
d. 120 V
43. A collector modulated transmitter
has a supply voltage of 24 V and
collector current of 0.5 A. The
modulator power for 100 percent
modulation is
a. 6 W
b. 12 W
c. 18 W
d. 24 W
44. The circuit that recovers the
original modulating information
from an AM signal is known as a
a. Modulator
b. Demodulator
c. Mixer
d. Crystal set
45. The most commonly used
amplitude demodulator is the
a. Diode mixer
b. Balanced modulator
c. Envelope detector
d. Crystal filter
Reviewer
46. A circuit that generates the upper
and lower sidebands but no carrier
is called a(n)
a. Amplitude modulator
b. Diode detector
c. Class C amplifier
d. Balanced modulator
47. The inputs to a balance modulator
are 1 MHz and a carrier of 1.5
MHz. The outputs are
a. 500 kHz
b. 2.5 MHz
c. 1.5 MHz
d. Both a and b
48. A widely used balanced modulator
is called the
a. Diode bridge circuit
b. Full-wave bridge rectifier
c. Lattice Modulator
d. Balanced bridge modulator
49. In a diode ring modulator, the
diodes act like
a. Variable resistors
b. Switches
c. Rectifiers
d. Variable capacitors
50. The output of a balanced
modulator is
a. AM
b. FM
c. SSB
d. DSB
e.
PART 5
(Source: Radio Receivers MCQ Test)
1. The first radio receivers invented
by
a. Marconi
b. Oliver Lodge
c. Alexander Popov
d. All of the above
2. We should use ______ to prevent
overloading of the IF amplifier in
a receiver.
a. Squelch
b. Variable selectivity
c. Variable sensitivity
d. Double conversion
3. Which of the following circuits
can not demodulate SSB?
a. Product modulator
b. Balance modulator
4.
5.
6.
7.
8.
9.
c. Phase discriminator
d. None of the above
________ is not a useful quantity
for comparing the noise
performance of receivers.
a. Noise figure
b. Noise temperature
c. Input noise voltage
d. Equivalent noise
resistance
Why A notch filter is sometimes
used in communication
receivers?
a. Spread the bandwidth
b. Made selectivity more
precise
c. Reduce receiver gain at
some specific frequency
d. Increase receiver gain at
some specific frequency
For which purpose EM 84 tube is
used in radio receivers?
a. Magic eye
b. RF amplifier
c. Audio amplifier
d. Full wave rectifier
What is the selectivity of a radio
receiver?
a. Its ability to suppress
noise
b. Its ability to amplify weak
signals
c. Its ability to reject adjacent
unwanted signals
d. None of the above
............. does not happen in
transistors?
a. Shot noise
b. Flicker noise
c. Partition noise
d. Resistance noise
What happens, if the intermediate
frequency is too low in a radio
receiver?
a. Selectivity will be too
sharp
b. Image-frequency rejection
will improve
c. The frequency selectivity
of the local oscillator will
have to be lowered
d. All of the above
Reviewer
10. The local oscillator is tuned to a
frequency ............... In a radio
receiver.
a. Equal to incoming
frequency
b. Lower than the incoming
frequency
c. Higher than the incoming
frequency
d. None of the above
11. The selectivity of most receivers
is determined largely by .......
a. Sensitivity
b. Antenna direction
c. Characteristics of IF
section
d. All of the above
12. What does a transmitter serial
current contain?
a. Audio frequencies
b. carrier frequencies
c. Radio frequencies
d. All of the above
13. What happens, if the intermediate
frequency is too high in a radio
receiver?
a. Selectivity will be poor
b. Tracking difficulties will be
least
c. Adjacent channel
rejection will improve
d. None of the above
14. Which of the following device has
IF input but RF output in a
receiver?
a. Loudspeaker
b. Demodulator
c. Audio amplifier
d. Frequency changer
15. For which purpose, the
neutralization is used in RF
amplifiers?
a. Stop oscillation
b. Improve selectivity
c. Increase bandwidth
d. None of the above
16. A duplexer is a device used to
.................
a. Connect two transmitters
to the same antenna
b. Feed more than one
receiver from a single
antenna
c. Connect a receiver and a
transmitter to the same
antenna
d. None of the above
17. RF amplifiers are used in radio
receivers for which purpose?
a. Improved image
frequency rejection
b. Improved rejection of
adjacent unwanted signals
c. Prevention of re-radiation
of the local oscillator
through the antenna of the
receiver
d. All of the above
18. .............. should be used in order
to prevent overloading or the last
IF amplifier in a receiver.
a. Squelch
b. Double conversion
c. Variable sensitivity
d. Variable selectivity
19. Which of the following oscillator is
used as a local oscillator in a
radio receiver?
a. Crystal
b. Hartley
c. Phase Shift
d. Wien-bridge
20. Which of the following is the
function of radio receiver?
a. Produce radio waves
b. Modulate a message
signal
c. Convert one form of
energy into other
d. Detect and amplify
information signal from the
carrier
PART 6
(Source: Radio Receiver Theorem
Question & Answers)
Part 1 out of 4
1. Which one of the following
receivers receives the broadcast
of music or speech from
amplitude modulation
transmitters that operates on
short, medium, or long wave
bands?
Reviewer
2.
3.
4.
5.
6.
7.
8.
a. Frequency
b. Amplitude
c. Pulse
d. None of the above
The insufficient selectivity in
tuned radio frequency receiver is
due to _______________ ?
a. Oscillatory nature of radio
frequency amplifiers
b. Variation in Q
c. Increased bandwidth
d. All of the above
The poor adjacent channel
rejection results when the
intermediate frequency is
__________________ ?
a. High
b. Very High
c. Moderate
d. Poor
The image frequency rejection
becomes poor when the
intermediate frequency is
__________________ ?
a. High
b. Very High
c. Moderate
d. Low
Which one of the following
intermediate frequencies makes
the selectivity too sharp?
a. High IF
b. Low IF
c. Very low IF
d. None of the above
Which one of the following
antennae is a wire type of
antenna?
a. Dipoles
b. Biconical
c. Reflector
d. Both a and b
The variation in bandwidth over
tuning range in tuned radio
frequency receiver is due to
_______________ ?
a. Oscillatory nature of radio
frequency amplifiers
b. Variation in Q
c. Increased bandwidth
d. All of the above
Which one of the following is a
type of highly directional
antenna?
a. Dipole, Collinear
b. Panel, yagi
c. Phased array
d. Parabolic dish
9. The horizontal beamwidth is 30 to
180 degrees in
_______________ antenna?
a. Parabolic dish
b. Omnidirectional
c. Patch/panel
d. Both a and b
10. The figure shown below is a
block diagram of
____________________
receiver?
a. Block Diagram of a
Superheterodyne Receiver
b. Superheterodyne
c. Tuned radio frequency
d. Simple radio receiver
e. None of the above
11. Which one of the following
components converts the audio
signals into sound waves?
a. Loudspeakers
b. Detector
c. Tuned circuit
d. AF amplifier
12. Which one of the following
components acts as an oscillator
as well as a mixer?
a. Amplifiers
b. Generators
c. Self-excited mixer
d. All of the above
13. What is the standard form of
AGC?
a. Automatic Gain Control
b. Alternate Gain Control
c. Automatic Gain Code
d. None of the above
14. In which one of the following
automatic gain control the shifting
operating point is towards the
cutoff?
a. Reverse
b. Forward
Reviewer
c. Both a and b
d. None of the above
15. The frequency range of amplitude
modulation radio receiver is
between ________________ ?
a. 100KHz to 1600KHz
b. 5 kHz to 1600KHz
c. 540 kHz to 1600KHz
d. None of the above
Part 2 out of 4
16. What is the standard form of
VLC?
a. Visible Light
Communication
b. Variable Light
Communication
c. Visible Light Control
d. None of the above
17. What are the functions of the
radio receiver?
a. Amplify’s the RF signal
b. Demodulates the selected
signal
c. Selects the desired
signals and rejects the
unwanted signal
d. All of the above
18. The horizontal beamwidth is 360
degrees in _______________
antenna?
a. Parabolic dish
b. Omnidirectional
c. Patch/panel
d. Both a and b
19. Which one of the following
antennae is a linearly polarised
type of antenna?
a. Dipoles
b. Biconical
c. Reflector
d. Both a and b
20. The figure shown below is a
block diagram of
________receiver?
a. Superheterodyne
b. Tuned radio frequency
c. Simple radio receiver
d. None of the above
21. Which one of the following
components amplifies the audio
signals?
a. Loudspeakers
b. Detector
c. Tuned circuit
d. AF amplifier
22. Which one of the following
components is used to adjust the
local oscillator frequency?
a. Amplifiers
b. Antenna
c. Self-excited mixer
d. Automatic gain control
23. Which one of the following
receivers receives the broadcast
from frequency modulation
transmitters that operates in ultrahigh or very high-frequency
bands?
a. Frequency
b. Amplitude
c. Pulse
d. None of the above
24. The tuning range of microwave
and radar receivers is from 1GHz
to ________________ GHz?
a. 10KHz
b. 30GHz
c. 10GHz
d. 160GHz
25. When the modulation index
increases in frequency
modulation signal the power
remain _________________ ?
a. Increases
b. Decreases
c. Constant
d. None of the above
26. Which one of the following
components in the FM receiver is
used to increase the radio signal
power?
a. Antenna
b. Electronic filters
c. Amplifier
d. All of the above
27. Which one of the receivers is a
double frequency conversion?
a. Superheterodyne
b. Tuned radio frequency
Reviewer
c. Communication
d. All of the above
28. The instability in tuned radio
frequency receiver is due to
_______________ ?
a. Oscillatory nature of radio
frequency amplifiers
b. Variation in Q
c. Increased bandwidth
d. All of the above
29. In which year the first radio
receiver was invented?
a. 1986
b. 1970
c. 1999
d. 2001
30. The figure shown below is a
block diagram of
____________________
receiver?
a.
b.
c.
d.
Superheterodyne
Tuned radio frequency
Simple radio receiver
None of the above
Part 3 out of 4
31. Which one of the following
components consists of capacitor
and inductor coil?
a. Loudspeakers
b. Detector
c. Tuned circuit
d. AF amplifier
32. In which one of the following
automatic gain control the shifting
operating point is towards the
saturation?
a. Reverse
b. Forward
c. oth a and b
d. None of the above
33. The automatic gain controls are
categorized into
____________________ types?
a. One
b. Two
c. Three
d. Four
34. The frequency range of
frequency modulation radio
receiver is between
_____________ ?
a. 100K Hz to 1600 kHz
b. 88 kHz to 108 MHz
c. 540 kHz to 1600 kHz
d. None of the above
35. Which one of the following
receivers is used for the
reception of short wave
telephone signals and telegraph?
a. Communication
b. Amplitude
c. Radar
d. Television
36. The process of converting all
incoming RF signals to a lower
frequency is called
________________?
a. Heterodyne
b. Intermediate frequency
c. Communication
d. None of the above
37. Which one of the following parts
of the TRF receiver is used to
detect the signal?
a. RF section
b. AM detector
c. Audio section
d. All of the above
38. Which one of the following parts
of the TRF receiver is used to
demodulate the amplitude
modulation wave?
a. RF section
b. AM detector
c. Audio section
d. All of the above
39. The figure shown below is a
block diagram of
____________________
receiver?
a. Superheterodyne
b. Tuned radio frequency
c. Communication receiver
Reviewer
d. None of the above
40. Which one of the following
receivers used to receive
television broadcast in ultra-high
or very high-frequency bands?
a. Communication
b. Amplitude
c. Radar
d. Television
47. The figure shown below is a
block diagram of
____________________
receiver?
Part 4 out of 4
41. The tuning range of the MW
broadcast amplitude modulation
receiver is from 540KHz to
__________________ ?
a. 1040KHz
b. 1140KHz
c. 1340KHz
d. 1640KHz
42. In a radio receiver the
________________ oscillator is
used as a local oscillator?
a. Hartley
b. Crystal
c. Wein bridge
d. None of the above
43. Which one of the following
receivers is used to receive
ranging signals and radio
detection?
a. Television
b. Radar
c. FM receivers
d. Communication
44. Which is the advantage of a
tuned radio frequency receiver?
a. High sensitivity
b. Poor audio quality
c. Both a and b
d. None of the above
45. Which one of the following
receivers converts all incoming
RF signals to a lower frequency?
a. Television
b. Radar
c. Superheterodyne
d. Communication
46. How many batteries do crystal
radio receivers require?
a. One
b. Two
c. Three
d. Batteries are not required
a. FM receiver
b. Tuned radio frequency
c. Communication receiver
d. None of the above
48. Which one of the receivers is a
Single frequency conversion?
a. Superheterodyne
b. Tuned radio frequency
c. Communication
d. All of the above
49. Which one of the following
components in the FM receiver is
used to detect the frequency
waves?
a. Antenna
b. Electronic filters
c. Amplifier
d. All of the above
50. The range of radio frequency
transmitter and receiver is up to
_________________ meters?
a. 150 meters
b. 250 meters
c. 450 meters
d. 100 meters
PART 7
(Source:)
1. The image channel selectivity of
super heterodyne receiver
depends upona. IF amplifiers only
b. RF and IF amplifiers only
c. Pre-selector, RF and IF
amplifiers
d. Pre-selector and RF
amplifiers only
2. A receiver has poor IF selectisity.
It will therefore also have poor?
Reviewer
3.
4.
5.
6.
7.
a. Blocking
b. Double-spotting
c. Diversity-reception
d. Sensitivity
What is the correct sequence of
the blocks in an AM receiver from
receiving the signal to output?
a. RF amplifier - Mixer - IF
amplifier - Demodulator Audio amplifier
b. RF amplifier - Mixer - IF
amplifier - Audio amplifier Demodulator
c. IF amplifier - Demodulator
- RF amplifier - Mixer Audio Amplifier
d. Audio Amplifier - Mixer Demodulator - IF amplifier
- RF amplifier
Which of the followings are the
reasons for use of narrow-band
FM rather than wide-band FM?
I.
It improves signal to noise
ratio.
II. It reduces inter-channel
interference.
III. Efficient use of power for
better coverage.
a. I, II and III
b. II and III only
c. I and II only
d. III only
Which of the following contains a
limiter stage, a discriminator and
a de-emphasis circuit?
a. Direct FM transmitter
b. Indirect FM transmitter
c. Double Side Band AM
receiver
d. FM receiver
A Pre-emphasis circuit provides
extra noise immunity by
a. Boosting the base
frequencies
b. Amplifying the higher
audio frequencies
c. Pre-amplifying the whole
audio band
d. Converting the phase
modulation to FM
A radio receiver is tuned to 750
kHz and its oscillator frequency is
925 kHz. The image frequency
would be
a. 1000 kHz
b. 1100 kHz
c. 1170 kHz
d. 1125 kHz
8. The frequency to which the
incoming signal is changed in
super heterodyne reception is
called
a. amplitude frequency
b. radio frequency
c. intermediate frequency
d. modulated frequency
9. If a radio receiver amplifies all the
signal frequency equally well, it is
said to have high
a. Fidelity
b. Sensitivity
c. Selectivity
d. Distortion
10. The standard IF value for AM
SHD receivers is
a. 550 kHz
b. 455 kHz
c. 660 kHz
d. 720 kHz
11. The range of super-heterodyne
receive tuning when f_L0>f_c
with broadcast frequency ranges
540 to 1600 KHz
a. 85-1145 kHz
b. 540-1600 kHz
c. 995-2055 kHz
d. 1450-2510 kHz
12. A noise figure of an amplifier
does not depend on
a. bandwidth
b. Output power
c. Power input
d. None of the above
13. In a standard AM
superheterodyne receiver, if the
IF is 455kHz and the high-side
tuning is used, the local oscillator
frequency must vary between
a. 885kHz - 1585kHz
b. 85kHz - 1145kHz
c. 1005kHz - 2105kHz
d. 88kHz - 108kHz
14. The use of TRF receivers is limited
because of their
a. Poor fidelity
b. Poor SNR
Reviewer
c. Poor sensitivity
d. All of the above
15. Which of the following statements
are correct with reference to
superheterodyne receivers?
i.The main advantage of the
superheterodyne receiver is its better
tracking
ii. The main advantage of the
superheterodyne receiver is an
improvement in sensitivity
Iii. The image channel rejection in the
superheterodyne receiver comes from
the IF stage only
Iv. The image channel rejection in the
superheterodyne receiver comes from
the RF stage only
a. (i) and (ii) are correct
b. (ii) and (iii) are correct
c. (ii) and (iv) are correct
d. (i) and (iv) are correct
16. The intermediate frequency of a
superheterodyne receiver is 450kHz. If it
is tuned to 1200kHz, the image
frequency will be
a. 1600 kHz
b. 2100 kHz
c. 900 kHz
d. 750 kHz
17. In an AM system receiver. the mixer
translates the carrier frequency f_c to a
fixed intermediate frequency of 450 kHz.
Given a broadcast signal of frequency
900 kHz. What is the corresponding
image frequency when a
superhetrodyne receiver is employed
with local oscillator frequency greater
than the broadcast signal frequency?
a. 900 kHz
b. 1800 kHz
c. 800 kHz
d. 1350 kHz
18. The RF receiver's ability to reject
unwanted signal is called
A. Selective
B. Sensitivity
C. SNR
D. Efficiency
19. Boosting of higher frequency at the
transmitter is done by using
a. De-emphasis
b. AGC circuit
c. Pre-emphasis
d. Armstrong method
20. A communication receiver has an
intermediate frequency of 9MHz. What
is the frequency of the oscillator when it
is tuned to 15MHz?
a. 24 MHz
b. 12MHz
c. 9 MHz
d. 15 MHz
21. In a superheterodyne receiver, if the
intermediate frequency is 450kHz and
the signal frequency is 100kHz, then the
local oscillator frequency and image
frequency respectively are
a. 1450 kHz and 100 kHz
b. 550 kHz and 1900 kHz
c. 1450 kHz and 1990 kHz
d. 550 kHz and 1450 kHz
22. If a radio receiver, which of the
following stages does not need
alignment
a. TRF stage
b. IF stage
c. Antenna input stage
d. Audio stage
23.The boosting of higher modulating
frequencies in accordance with a
prearranged curve is called:
a. Pre-emphasis
b. curve fitting
c. De-emphasis
d. Reconstruction
24.In a broadcast superheterodyne
receiver, having no RF amplifier, the IF
= 455 kHz. What is the image frequency
if the receiver is tuned to 1000 kHz?
a. 1455 kHz
b. 1910 kHz
c. 545 kHz
d. 2455 kHz
Reviewer
25. A Superheterodyne receiver with an
intermediate frequency of 450 kHz is
tuned to a signal of 1600 kHz. The
image frequency is
a. 2500 kHz
b. 2050 kHz
c. 1600 kHz
d. 450 kHz
PART 8
(Source: Courseworks)
Coursework A
4. If a transmitter supplies 8kW to the
antenna when it is unmodulated, what is
the total radiated power when it is
modulated at 60%?
1. Which statement is true about index
modulation?
- Vmin
is
positive
in
undermodulation
2. The antenna current of an AM
transmitter is 10A when only the carrier is
sent but it increases to 10.95A when the
carrier is modulated by a single sine
wave. If 85% modulation is desired, what
should be the modulation index of the
second wave?
5. Which statement is not true about Am?
- An increase in the frequency of
the modulating signal increases
the amplitude of the AM signal
6. A 1000-W carrier is to be modulated to
a 90% level. Determine the total
transmitted power
ANS: 0.5679
3. An AM transmitter radiates 400W at
100% modulation. How much power is in
the sidebands?
7. With no modulating signal, what is the
output signal of an Amplitude Modulator?
- Carrier signal
8. Which of the following frequency
cannot be found in an Am signal?
- FM
9. An AM DSBFC transmitter with an
unmodulated carrier power, Pc=600W
Reviewer
that is modulated simultaneously by four
tones, m1=0.1, m2=0.2, m3=0.4,
m5=0.5, determine the total sideband
power
12. What is not an advantage of SSB AM
over DSBAM?
- It is more simple to generate and
demodulate suppressed carrier
AM than full carrier AM
10. An AM broadcast station operates at
its maximum allowed total output of
50kW and at 85% modulation. How much
is the % power of the carrier?
13. What type of modulation is used to
send the picture portion of a TV signal
- CF3
14. In the FCC Emission Designation the
first symbol indicates
- The type of modulation of the main
carrier
15. CB radios were developed using the
full-carrier DSB AM. It operates using 40
channels, each 10KHz wide. When the
SSBSC is used, the same carrier
frequencies are used as with the
conventional AM but the transceivers are
switchable to either lower or upper
sideband. How many channels are
available when the SSB is used?
80
Coursework B
11. Anticipating single sideband AM,
what percentage of the total power is
saved by suppressing the carrier and one
sideband while transmitting the other
sideband only for m=0.75?
16. An AM wave has a total transmitted
power of 4kW when modulated 85%.
What is the total transmitted power if J3E
was used instead?
Reviewer
18. If a transmitter power of 100W is
sufficient for reliable communication over
a certain path using the SSB, What is the
power required for a double sideband
full-carrier AM?
17. How much is the % power saving if
R3E was used at m=0.8
19. To provide two or more voice circuits
with the same carrier, it is necessary to
use the
- B8E
20. What is the circuit used to produce
DSBSC AM?
- Diode ring modulator
Coursework c:
21. Which receiver component limits the
image frequency from entering the mixer
a. Pre selector
b. Low pass audio filter
c. IF filter strips
d. demodulator
22. For an AM receiver turned to a station
at 590kHz with IF=455 kHz, calculate the
image frequency rejection in dB. Assume
that the input filter consists of one tuned
circuit with a Q of 40.
Reviewer
38.6867
23. A superheterodyne receiver is tuned
to a frequency of 5MHz when the
oscillator frequency is 6.85MHz. What is
the Intermediate Frequency in MHz?
b. Baseband frequency
c. Carrier frequency
d. Intermediate frequency
29. A receiver for a signal at 150 MHz
uses a 10.7-MHz IF and low tracking.
Calculate the LO frequency in MHz. Do
not include the unit in the final answer.
139.30
30. A superheterodyne is tuned to 2738
kHz. The IF is 475 kHz. What is the
image frequency in KHz. Do not include
the unit in the final answer.
3688
24. Which of the following is true about
image frequency when it is allowed to
enter at the receiver
a. When mixed together with the
local oscillator will produce a
desired IF
b. Will
produce
a
usable
demodulated signal at the
receiver
c. Will produce an undesired
intermediate
frequency
that
contains no information
d. Is always higher than the desired
RF signal
25. For an IF frequency of 455 kHz, what
must be the LO frequency (in KHz) when
receiving a 580 kHz transmission?
Assume high side injection. Do not
include unit in the final answer
1035
26. The higher the quality factor
a. The higher the image frequency
b. The higher the intermediate
frequency
c. The higher the IFRR
d. Has no effect in IFRR
27. Which of the following is an
advantage of TRF receivers?
a. Sufficient
image
frequency
rejection
b. Good sensitivity
c. Superior fidelity
d. Good selectivity
28. The output of a Mixer is called
a. Image frequency
31. An amplifier is used in receivers to
improve
a. Shape factor
b. Fidelity
c. Sensitivity
d. selectivity
32. Heterodyning means
a. Mixing of 2 signals to get the
difference frequency
b. Multiplication between 2 signals
c. Doubling the signal frequency
d. Filtering the unwanted signals
33. Which part of the Superheterodyne
receiver provides the initial sensitivity
a. RF amplifier
b. Audio amplifier
c. Antenna
d. preselector
34. The ability of a receiver to produce a
faithful output with reference to the
original information is called
a. Sensitivity
b. Fidelity
c. Bass quality
d. selectivity
35. Which is not an example of a receiver
a. Microphone
b. Cellular phone car stereo
c. TV
Coursework d:
36. An FM broadcast station produces a
carrier swing of 90kHz. Calculate the
percentage modulation. Use max
frequency deviation as per FCC rule of
75kHz.
Reviewer
120
37. Indicate which one of the following is
not an advantage of FM over AM.
- Lower sideband is required
38. An FM transmitter has an output
power of 500W when it is not modulated.
When intelligence is added, its
modulation index is 2.0. What is its output
power (in Watts) with a modulation index
of 2.0?
500W
39. The amount of frequency deviation is
dependent on the intelligence frequency
in.
- PM signal
40. Determine modulation index for a
frequency modulator with a deviation
sensitivity of 20kHz/V and a modulating
signal of 5cos2pi(2500)t.
5
45. A frequency modulated signal which
is modulated by a 3 kHz sine wave
reaches a maximum frequency of 100.02
MHz and minimum frequency of 99.98.
Determine the peak frequency deviation
in kHz. No unit in the final answer.
40
PART 9
(Source: Lesson 7)
PART 1
1. Determine the peak frequency
deviation and modulation index for
a frequency modulator with a
deviation sensitivity of 10 kHz/V
and a modulating signal of
5cos(2(2500)t).
answer.
40
41. The phenomenon of a strong FM
signal dominating a weaker signal on a
common frequency is referred to as the.
- Capture effect
42. Carson’s rule is used to approximate
the necessary
- Bandwidth
43. An FM signal has an intelligence
frequency of 5 kHz and a maximum
deviation of 20 kHz. How many
sidebands are produces with significant
amplitudes?
44. An FM signal has an intelligence
frequency of 2 kHz and a maximum
deviation of 10 kHz. If its carrier
frequency is set at 162.4 MHz, what is its
index of modulation?
2. An FM signal is defined by the
equation e 50 sin95 10 t 10 sin
5000t 6 FM V.
a. Find the carrier frequency.
b. Find the modulation frequency.
c. Find the modulation index.
d.Calculate
the
frequency
deviation
answer.
Reviewer
S
3. What is the modulation index of an
FM transmitter whose frequency
deviation is 50 kHz while its audio
frequency is 10 kHz?
answer.
4. Determine the practical bandwidth
of an FM signal modulated by a
15-kHz tone whose frequency
deviation is 45 kHz. What is the
approximate bandwidth for this
system using Carson’s formula?
answer.
5. When the modulating frequency in
an FM system is 500 Hz and the
modulating voltage is 2.6 V, the
modulation index is 40. Find the
maximum deviation. What is the
modulation index when the
modulating frequency is raised to
800 Hz and the modulating
voltage is simultaneously reduced
to 1.3 V?
answer.
6. What
is
the
approximate
frequency of the modulating signal
having a bandwidth of 15 kHz and
a frequency deviation of 6 kHz?
answer.
7. What is the deviation ratio of an
FM signal if the maximum
allowable deviation is 12 kHz and
the
maximum
intelligence
frequency is 4 kHz?
answer.
8. The audio section of a TV
transmission employs frequency
modulation with a maximum
allowable deviation of 25 kHz.
Find the deviation ratio if the
highest intelligence frequency it
can handle is 15 kHz.
answer.
Reviewer
9. An FM broadcast station operates
with a peak-to-peak deviation of
120
kHz.
Calculate
the
percentage modulation.
answer.
10. )What is the amount of carrier
swing necessary to produce an
80%
modulation
for
FM
broadcasting?
answer.
13. For a modulation index of 1.5, find
the power at the sidebands if the
total power dissipated is 20 kW.
answer.
14. In an FM system, when the audio
frequency is 500 Hz and the AF
voltage is 2.4 V, the deviation is
4.8 kHz. If the AF voltage is now
increased to 7.2 V, what is the
new deviation? If the AF is
dropped to 200 Hz and AF voltage
is raised to 10 V what is the new
deviation? Find the modulation
index in each case.
answer.
11. A modulating frequency range
from 30 Hz to 15 kHz is permitted
in an FM system together with a
maximum deviation of 50 kHz.
What will be the minimum and
maximum possible values of the
modulation index?
answer.
12. What is the BW required for an FM
signal in which the modulating
frequency is 2 kHz and the
maximum deviation is 10 kHz? 8
pairs of sidebands are included.
answer.
15. A frequency modulated signal
which is modulated by a 3-kHz
sine wave reaches a maximum
frequency of 100.02 MHz and
minimum frequency of 99.98MHz.
(a) Determine the carrier swing,
(b) Find the carrier frequency,
(c) Calculate the frequency
deviation of the signal,
(d) What is the modulation index
of the signal.
answer.
Reviewer
d. Band-pass filter
6) The FM produced by PM is called
a. direct FM
b. indirect FM
c. direct PM
d. indirect AM
PART 2
1) On an FM signal, maximum deviation
occurs at what point on the
modulating signal?
a. positive peak amplitude
b. negative peak amplitude
c. both positive and negative peak
amplitude
d. none of the above
2) In PM, a frequency shift occurs while
what characteristic of the modulating
signal is changing?
a. Amplitude
b. Frequency
c. Phase angle
d. Angle
3) Maximum frequency deviation of a PM
signal occurs at
a. positive peak points
b. negative peak points
c. Zero crossing points
d. none of the above
4) In PM, carrier frequency deviation is
not proportional to:
a. carrier amplitude
b. carrier frequency
c. carrier amplitude and frequency
d. intelligence amplitude
5) To compensate for increases in carrier
frequency deviation with an
increase in modulating signal frequency,
what circuit is used between the
modulating signal and the phase
modulator?
a. Low-pass filter
b. High-pass filter
c. Band-stop filter
7) If the amplitude of the modulating
signal applied to a phase modulator is
constant, the output signal will be
a. the modulating frequency
b. the carrier frequency
c. the intelligence amplitude
d. the carrier amplitude
8) c
index is
a. 250
b. 0.08
c. 2
d. 12.5
9) The maximum deviation of an FM
carrier is 2 kHz by a maximum
modulating signal of 400 Hz. The
deviation ratio is
a. 5
b. 0.2
c. 800
d. none of the above
10) A 70 kHz carrier has a frequency
deviation of 4kHz with a 1000Hz signal.
How many significant sideband pairs are
produced?
a. 17.5
b. 0.25
c. 7
d. None of the above