E8B FCC emission designators versus
emission types; modulation
symbols and transmission characteristics; modulation methods;
modulation index; deviation ratio; pulse modulation: width; position
E8B01
(A)
What is
emission A3C?
A. Facsimile
B. RTTY
C. ATV
D. Slow Scan TV
E8B02
(B)
What
type of emission is produced when an AM transmitter is modulated by a facsimile
signal?
A. A3F
B. A3C
C. F3F
D. F3C
E8B03
(C)
What
does a facsimile transmission produce?
A. Tone-modulated telegraphy
B. A pattern of printed characters designed to
form a picture
C. Printed pictures by
electrical means
D. Moving pictures by electrical means
E8B04
(D)
What is
emission F3F?
A. Modulated CW
B. Facsimile
C. RTTY
D. Television
E8B05
(D)
What
type of emission is produced when an SSB transmitter is modulated by a
slow-scan television signal?
A. J3A
B. F3F
C. A3F
D. J3F
E8B06
(B)
If the
first symbol of an ITU emission designator is J, representing a
single-sideband, suppressed-carrier signal, what information about the emission
is described?
A. The nature of any signal multiplexing
B. The type of modulation of
the main carrier
C. The maximum permissible bandwidth
D. The maximum signal level, in decibels
E8B07
(C)
If the
second symbol of an ITU emission designator is 1, representing a single channel
containing quantized, or digital information, what information about the
emission is described?
A. The maximum transmission rate, in bauds
B. The maximum permissible deviation
C. The nature of signals
modulating the main carrier
D. The type of information to be transmitted
E8B08
(D)
If the
third symbol of an ITU emission designator is D, representing data
transmission, telemetry or telecommand, what information about the emission is
described?
A. The maximum transmission rate, in bauds
B. The maximum permissible deviation
C. The nature of signals modulating the main
carrier
D. The type of information
to be transmitted
E8B09
(A)
How can
the unwanted sideband be removed from a double-sideband signal generated by a
balanced modulator to produce a single-sideband phone signal?
A. By filtering
B. By heterodyning
C. By mixing
D. By neutralization
E8B10
(D)
How
does the modulation index of a phase-modulated emission vary with RF carrier
frequency (the modulated frequency)?
A. It increases as the RF carrier frequency
increases
B. It decreases as the RF carrier frequency
increases
C. It varies with the square root of the RF
carrier frequency
D. It does not depend on the
RF carrier frequency
E8B11
(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
E8B12
(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
E8B13
(D)
What is
the deviation ratio of 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
E8B14
(A)
In a
pulse-modulation system, why is the transmitter's peak power much greater than
its average power?
A. The signal duty cycle is
less than 100%
B. The signal reaches peak amplitude only when
voice modulated
C. The signal reaches peak amplitude only when
voltage spikes are generated within the modulator
D. The signal reaches peak amplitude only when
the pulses are also amplitude modulated
E8B15
(C)
What is
one way that voice is transmitted in a pulse-width modulation system?
A. A standard pulse is varied in amplitude by
an amount depending on the voice waveform at that instant
B. The position of a standard pulse is varied
by an amount depending on the voice waveform at that instant
C. A standard pulse is
varied in duration by an amount depending on the voice waveform at that instant
D. The number of standard pulses per second
varies depending on the voice waveform at that instant
E8B16
(A)
What
function does a pulse-width modulator perform in a switching regulator power
supply?
A. It turns the switch
transistor on and off at the proper time to ensure smooth regulation
B. It increases and decreases the load current
at the proper time to ensure smooth regulation
C. It increases or decreases the frequency of
the input voltage to ensure that AC pulses are sent at regular intervals to the
rectifier
D. It turns the rectifier on and off at regular
intervals to avoid overheating the power supply