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ELE4AH
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1992-01-26
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FCC ADVANCED Exam Question Pool. Subelement 4AH.
Signals and Emissions. 6 Questions.
---------------------------------------------------
4AH 1.1 A
What is emission A3C?
A. Facsimile
B. RTTY
C. ATV
D. Slow Scan TV
4AH 1.2 B
What type of emission is produced when an amplitude modulated transmitter is
modulated by a facsimile signal?
A. A3F
B. A3C
C. F3F
D. F3C
4AH 1.3 C
What is facsimile?
A. The transmission of tone-modulated telegraphy
B. The transmission of a pattern of printed characters designed to form a
picture
C. The transmission of printed pictures by electrical means
D. The transmission of moving pictures by electrical means
4AH 1.4 D
What is emission F3C?
A. Voice transmission
B. Slow Scan TV
C. RTTY
D. Facsimile
4AH 1.5 A
What type of emission is produced when a frequency modulated transmitter is
modulated by a facsimile signal?
A. F3C
B. A3C
C. F3F
D. A3F
4AH 1.6 B
What is emission A3F?
A. RTTY
B. Television
C. SSB
D. Modulated CW
4AH 1.7 B
What type of emission is produced when an amplitude modulated transmitter is
modulated by a television signal?
A. F3F
B. A3F
C. A3C
D. F3C
4AH 1.8 D
What is emission F3F?
A. Modulated CW
B. Facsimile
C. RTTY
D. Television
4AH 1.9 C
What type of emission is produced when a frequency modulated transmitter is
modulated by a television signal?
A. A3F
B. A3C
C. F3F
D. F3C
4AH 1.10 D
What type of emission results when a single sideband transmitter is used for
slow-scan television?
A. J3A
B. F3F
C. A3F
D. J3F
4AH 2.1 C
How can an FM-phone signal be produced?
A. By modulating the supply voltage to a class-B amplifier
B. By modulating the supply voltage to a class-C amplifier
C. By using a reactance modulator on an oscillator
D. By using a balanced modulator on an oscillator
4AH 2.2 D
How can a double-sideband phone signal be produced?
A. By using a reactance modulator on an oscillator
B. By varying the voltage to the varactor in an oscillator circuit
C. By using a phase detector, oscillator and filter in a feedback loop
D. By modulating the plate supply voltage to a class C amplifier
4AH 2.3 A
How can a single-sideband phone signal be produced?
A. By producing a double sideband signal with a balanced modulator and then
removing the unwanted sideband by filtering
B. By producing a double sideband signal with a balanced modulator and then
removing the unwanted sideband by heterodyning
C. By producing a double sideband signal with a balanced modulator and then
removing the unwanted sideband by mixing
D. By producing a double sideband signal with a balanced modulator and then
removing the unwanted sideband by neutralization
4AH 3.1 B
What is meant by the term deviation ratio?
A. The ratio of the audio modulating frequency to the center carrier
frequency
B. The ratio of the maximum carrier frequency deviation to the highest audio
modulating frequency
C. The ratio of the carrier center frequency to the audio modulating
frequency
D. The ratio of the highest audio modulating frequency to the average audio
modulating frequency
4AH 3.2 C
In an FM-phone signal, what is the term for the maximum deviation from the
carrier frequency divided by the maximum audio modulating frequency?
A. Deviation index
B. Modulation index
C. Deviation ratio
D. Modulation ratio
4AH 3.3 D
What is the deviation ratio for an FM-phone signal having a maximum
frequency swing of plus or minus 5 kHz and accepting a maximum modulation
rate of 3 kHz?
A. 60
B. 0.16
C. 0.6
D. 1.66
4AH 3.4 A
What is the deviation ratio of an FM-phone signal having a maximum frequency
swing of plus or minus 7.5 kHz and accepting a maximum modulation rate of
3.5 kHz?
A. 2.14
B. 0.214
C. 0.47
D. 47
4AH 4.1 B
What is meant by the term modulation index?
A. The processor index
B. The ratio between the deviation of a frequency modulated signal and the
modulating frequency
C. The FM signal-to-noise ratio
D. The ratio of the maximum carrier frequency deviation to the highest audio
modulating frequency
4AH 4.2 D
In an FM-phone signal, what is the term for the ratio between the deviation
of the frequency-modulated signal and the modulating frequency?
A. FM compressibility
B. Quieting index
C. Percentage of modulation
D. Modulation index
4AH 4.3 D
How does the modulation index of a phase-modulated emission vary with the
modulated frequency?
A. The modulation index increases as the RF carrier frequency (the modulated
frequency) increases
B. The modulation index decreases as the RF carrier frequency (the modulated
frequency) increases
C. The modulation index varies with the square root of the RF carrier
frequency (the modulated frequency)
D. The modulation index does not depend on the RF carrier frequency (the
modulated frequency)
4AH 4.4 A
In an FM-phone signal having a maximum frequency deviation of 3000 Hz either
side of the carrier frequency, what is the modulation index when the
modulating frequency is 1000 Hz?
A. 3
B. 0.3
C. 3000
D. 1000
4AH 4.5 B
What is the modulation index of an FM-phone transmitter producing an
instantaneous carrier deviation of 6 kHz when modulated with a 2-kHz
modulating frequency?
A. 6000
B. 3
C. 2000
D. 1/3
4AH 5.1 C
What are electromagnetic waves?
A. Alternating currents in the core of an electromagnet
B. A wave consisting of two electric fields at right angles to each other
C. A wave consisting of an electric field and a magnetic field at right
angles to each other
D. A wave consisting of two magnetic fields at right angles to each other
4AH 5.2 D
What is a wave front?
A. A voltage pulse in a conductor
B. A current pulse in a conductor
C. A voltage pulse across a resistor
D. A fixed point in an electromagnetic wave
4AH 5.3 A
At what speed do electromagnetic waves travel in free space?
A. Approximately 300 million meters per second
B. Approximately 468 million meters per second
C. Approximately 186,300 feet per second
D. Approximately 300 million miles per second
4AH 5.4 B
What are the two interrelated fields considered to make up an
electromagnetic wave?
A. An electric field and a current field
B. An electric field and a magnetic field
C. An electric field and a voltage field
D. A voltage field and a current field
4AH 5.5 C
Why do electromagnetic waves not penetrate a good conductor to any great
extent?
A. The electromagnetic field induces currents in the insulator
B. The oxide on the conductor surface acts as a shield
C. Because of Eddy currents
D. The resistivity of the conductor dissipates the field
4AH 6.1 D
What is meant by referring to electromagnetic waves traveling in free space?
A. The electric and magnetic fields eventually become aligned
B. Propagation in a medium with a high refractive index
C. The electromagnetic wave encounters the ionosphere and returns to its
source
D. Propagation of energy across a vacuum by changing electric and magnetic
fields
4AH 6.2 A
What is meant by referring to electromagnetic waves as horizontally
polarized?
A. The electric field is parallel to the earth
B. The magnetic field is parallel to the earth
C. Both the electric and magnetic fields are horizontal
D. Both the electric and magnetic fields are vertical
4AH 6.3 B
What is meant by referring to electromagnetic waves as having circular
polarization?
A. The electric field is bent into a circular shape
B. The electric field rotates
C. The electromagnetic wave continues to circle the earth
D. The electromagnetic wave has been generated by a quad antenna
4AH 6.4 C
When the electric field is perpendicular to the surface of the earth, what
is the polarization of the electromagnetic wave?
A. Circular
B. Horizontal
C. Vertical
D. Elliptical
4AH 6.5 D
When the magnetic field is parallel to the surface of the earth, what is the
polarization of the electromagnetic wave?
A. Circular
B. Horizontal
C. Elliptical
D. Vertical
4AH 6.6 A
When the magnetic field is perpendicular to the surface of the earth, what
is the polarization of the electromagnetic field?
A. Horizontal
B. Circular
C. Elliptical
D. Vertical
4AH 6.7 B
When the electric field is parallel to the surface of the earth, what is the
polarization of the electromagnetic wave?
A. Vertical
B. Horizontal
C. Circular
D. Elliptical
4AH 7.1 B
What is a sine wave?
A. A constant-voltage, varying-current wave
B. A wave whose amplitude at any given instant can be represented by a point
on a wheel rotating at a uniform speed
C. A wave following the laws of the trigonometric tangent function
D. A wave whose polarity changes in a random manner
4AH 7.2 C
How many times does a sine wave cross the zero axis in one complete cycle?
A. 180 times
B. 4 times
C. 2 times
D. 360 times
4AH 7.3 D
How many degrees are there in one complete sine wave cycle?
A. 90 degrees
B. 270 degrees
C. 180 degrees
D. 360 degrees
4AH 7.4 A
What is the period of a wave?
A. The time required to complete one cycle
B. The number of degrees in one cycle
C. The number of zero crossings in one cycle
D. The amplitude of the wave
4AH 7.5 B
What is a square wave?
A. A wave with only 300 degrees in one cycle
B. A wave which abruptly changes back and forth between two voltage levels
and which remains an equal time at each level
C. A wave that makes four zero crossings per cycle
D. A wave in which the positive and negative excursions occupy unequal
portions of the cycle time
4AH 7.6 C
What is a wave called which abruptly changes back and forth between two
voltage levels and which remains an equal time at each level?
A. A sine wave
B. A cosine wave
C. A square wave
D. A rectangular wave
4AH 7.7 D
Which sine waves make up a square wave?
A. 0.707 times the fundamental frequency
B. The fundamental frequency and all odd and even harmonics
C. The fundamental frequency and all even harmonics
D. The fundamental frequency and all odd harmonics
4AH 7.8 A
What type of wave is made up of sine waves of the fundamental frequency and
all the odd harmonics?
A. Square wave
B. Sine wave
C. Cosine wave
D. Tangent wave
4AH 7.9 B
What is a sawtooth wave?
A. A wave that alternates between two values and spends an equal time at
each level
B. A wave with a straight line rise time faster than the fall time (or vice
versa)
C. A wave that produces a phase angle tangent to the unit circle
D. A wave whose amplitude at any given instant can be represented by a point
on a wheel rotating at a uniform speed
4AH 7.10 C
What type of wave is characterized by a rise time significantly faster than
the fall time (or vice versa)?
A. A cosine wave
B. A square wave
C. A sawtooth wave
D. A sine wave
4AH 7.11 D
Which sine waves make up a sawtooth wave?
A. The fundamental frequency and all prime harmonics
B. The fundamental frequency and all even harmonics
C. The fundamental frequency and all odd harmonics
D. The fundamental frequency and all harmonics
4AH 7.12 A
What type of wave is made up of sine waves at the fundamental frequency and
all the harmonics?
A. A sawtooth wave
B. A square wave
C. A sine wave
D. A cosine wave
4AH 8.1 C
What is the meaning of the term root mean square value of an AC voltage?
A. The value of an AC voltage found by squaring the average value of the
peak AC voltage
B. The value of a DC voltage that would cause the same heating effect in a
given resistor as a peak AC voltage
C. The value of an AC voltage that would cause the same heating effect in a
given resistor as a DC voltage of the same value
D. The value of an AC voltage found by taking the square root of the average
AC value
4AH 8.2 C
What is the term used in reference to a DC voltage that would cause the same
heating in a resistor as a certain value of AC voltage?
A. Cosine voltage
B. Power factor
C. Root mean square
D. Average voltage
4AH 8.3 D
What would be the most accurate way of determining the RMS voltage of a
complex waveform?
A. By using a grid dip meter
B. By measuring the voltage with a D'Arsonval meter
C. By using an absorption wavemeter
D. By measuring the heating effect in a known resistor
4AH 8.4 A
What is the RMS voltage at a common household electrical power outlet?
A. 117-V AC
B. 331-V AC
C. 82.7-V AC
D. 165.5-V AC
4AH 8.5 B
What is the peak voltage at a common household electrical outlet?
A. 234 volts
B. 165.5 volts
C. 117 volts
D. 331 volts
4AH 8.6 C
What is the peak-to-peak voltage at a common household electrical outlet?
A. 234 volts
B. 117 volts
C. 331 volts
D. 165.5 volts
4AH 8.7 D
What is RMS voltage of a 165-volt peak pure sine wave?
A. 233-V AC
B. 330-V AC
C. 58.3-V AC
D. 117-V AC
4AH 8.8 A
What is the RMS value of a 331-volt peak-to-peak pure sine wave?
A. 117-V AC
B. 165-V AC
C. 234-V AC
D. 300-V AC
4AH 9.1 C
For many types of voices, what is the ratio of PEP to average power during
a modulation peak in a single-sideband phone signal?
A. Approximately 1.0 to 1
B. Approximately 25 to 1
C. Approximately 2.5 to 1
D. Approximately 100 to 1
4AH 9.2 C
In a single-sideband phone signal, what determines the PEP-to-average power
ratio?
A. The frequency of the modulating signal
B. The degree of carrier suppression
C. The speech characteristics
D. The amplifier power
4AH 9.3 C
What is the approximate DC input power to a Class B RF power amplifier stage
in an FM-phone transmitter when the PEP output power is 1500 watts?
A. Approximately 900 watts
B. Approximately 1765 watts
C. Approximately 2500 watts
D. Approximately 3000 watts
4AH 9.4 B
What is the approximate DC input power to a Class C RF power amplifier stage
in a RTTY transmitter when the PEP output power is 1000 watts?
A. Approximately 850 watts
B. Approximately 1250 watts
C. Approximately 1667 watts
D. Approximately 2000 watts
4AH 9.5 D
What is the approximate DC input power to a Class AB RF power amplifier
stage in an unmodulated carrier transmitter when the PEP output power is 500
watts?
A. Approximately 250 watts
B. Approximately 600 watts
C. Approximately 800 watts
D. Approximately 1000 watts
4AH 10.1 D
Where is the noise generated which primarily determines the signal-to-noise
ratio in a 160-meter wavelength band receiver?
A. In the detector
B. Man-made noise
C. In the receiver front end
D. In the atmosphere
4AH 10.2 A
Where is the noise generated which primarily determines the signal-to-noise
ratio in a 2-meter wavelength band receiver?
A. In the receiver front end
B. Man-made noise
C. In the atmosphere
D. In the ionosphere
4AH 10.3 B
Where is the noise generated which primarily determines the signal-to-noise
ratio in a 1.25-meter wavelength band receiver?
A. In the audio amplifier
B. In the receiver front end
C. In the ionosphere
D. Man-made noise
4AH 10.4 C
Where is the noise generated which primarily determines the signal-to-noise
ratio in a 0.70-meter wavelength band receiver?
A. In the atmosphere
B. In the ionosphere
C. In the receiver front end
D. Man-made noise
--------------------------------------------------
End of Subelement 4AH.