Current Shareware 1994 January/SHAR194.ISO/hamradio/adv21.zip/ADV8.DAT

Text File | 1993-03-09 | 16KB | 495 lines

399H-1.3   C 8-1   Fax is pictures by electrical means
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
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400H-1.4   D 8-2   Third digit C for Fax
What is emission F3C?
A. Voice transmission
B. Slow Scan TV
C. RTTY
D. Facsimile
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401H-1.5   A 8-2   First digit F for FM |Third digit C for Fax
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
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402H-1.6   B 8-2   Third digit F for TV
What is emission A3F?
A. RTTY
B. Television
C. SSB
D. Modulated CW
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403H-1.7   B 8-2   First digit A for AM|Third digit F for TV
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
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404H-1.8   D 8-2   Third digit F for TV
What is emission F3F?
A. Modulated CW
B. Facsimile
C. RTTY
D. Television
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405H-1.9   C 8-2   First digit F for FM|Third digit F for TV
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
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406H-1.10  D 8-2   First digit J for SSB|Third digit F for TV
What type of emission results when a single sideband
transmitter is used for slow-scan television?
A. J3A
B. F3F
C. A3F
D. J3F
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407H-2.1   C 8-4   Vary the oscillator frequency|with a reactance modulator
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
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408H-2.2   D 8-3   Plate modulation
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
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409H-2.3   A 8-3   Filtering
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
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410H-3.1   B 8-5   Deviation/Modulating
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
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411H-3.2   C 8-5   Deviation ratio
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
*
412H-3.3   D 8-5   Deviation/Modulating|DR = 5000/3000
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
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413H-3.4   A 8-5   Deviation/Modulating|DR = 7500/3500
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
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414H-4.1   B 8-5   Deviation/Modulating
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
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415H-4.2   D 8-5   Modulation index
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
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416H-4.3   D 8-6   Independent
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)
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417H-4.4   A 8-5   Deviation/Modulating
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
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418H-4.5   B 8-5   Deviation/Modulating
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
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419H-5.1   C 8-6   Electric & magnetic
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
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420H-5.2   D 8-6   A point
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
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421H-5.3   A 8-6   300 million meters/second
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
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422H-5.4   B 8-6   Electric & magnetic
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
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423H-5.5   C 8-7   Eddy currents
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
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424H-6.1   D 8-6   In a vacuum
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
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425H-6.2   A 8-7   E-Field parallel to earth
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
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426H-6.3   B 8-7   E-field rotates
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
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427H-6.4   C 8-7   Vertical
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
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428H-6.5   D 8-7   E-Field is perpendicular|Polarization is vertical
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
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429H-6.6   A 8-7   E-Field is parallel to earth|Horizontal
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
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430H-6.7   B 8-7   Horizontal
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
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431H-7.1   B 8-7   A uniformly varying wave
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
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432H-7.2   C 8-8   Twice
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
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433H-7.3   D 8-8   360°
How many degrees are there in one complete sine wave
cycle?
A. 90 degrees
B. 270 degrees
C. 180 degrees
D. 360 degrees
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434H-7.4   A 8-8   Time to complete a cycle
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
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435H-7.5   B 8-9   Equal time at each level
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
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436H-7.6   C 8-9   Square wave
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
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437H-7.7   D 8-9   All odd
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
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438H-7.8   A 8-9   Square
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
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439H-7.9   B 8-8   Slow rise and fast fall|or vice versa
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
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440H-7.10  C 8-8   Sawtooth
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
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441H-7.11  D 8-8   All harmonics
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
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442H-7.12  A 8-8   Sawtooth
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
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443H-8.1   C 8-9   RMS give same heating as DC
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
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444H-8.2   C 8-9   RMS
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
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445H-8.3   D 8-9   Heat generated
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
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446H-8.4   A 8-10  Supposed to be 117
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
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447H-8.5   B 8-10  Vp = √2*RMS,  Vp = √2*117|Vp = 1.414*117,  Vp = 165
What is the peak voltage at a common household
electrical outlet?
A. 234 volts
B. 165.5 volts
C. 117 volts
D. 331 volts
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448H-8.6   C 8-10  Vpp = 2*√2*RMS |Vpp = 2*√2*117 |Vpp = 2.828*117
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
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449H-8.7   D 8-9   RMS = Vp/√2,  RMS = 165/1.414
What is the 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
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450H-8.8   A 8-9   RMS = .5*Vpp/√2   |RMS = .5*331/1.414|RMS = 117 VAC
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
*
451H-9.1   C 8-11  2.5:1
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
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452H-9.2   C 8-11  Speech characteristics when|modulated by talking
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
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453H-9.3   C 7-25  Class B efficiency ≈ 60% |1500/.60 = 2500
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
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454H-9.4   B 7-26  Class B efficiency ≈ 80% |1000/.80 = 1250
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
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455H-9.5   D 7-25  Class AB efficiency ≈ 50%|500/.50 = 1000
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
*