home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Media Share 9
/
MEDIASHARE_09.ISO
/
hamradio
/
hamtest.zip
/
ELE4BH
< prev
next >
Wrap
Text File
|
1992-01-26
|
11KB
|
476 lines
FCC EXTRA Exam Question Pool. Subelement 4BH.
Signals and Emissions. 4 Questions.
---------------------------------------------------
4BH 1A1 A
In a pulse-width modulation system, what parameter does the
modulating signal vary?
A. Pulse duration
B. Pulse frequency
C. Pulse amplitude
D. Pulse intensity
4BH 1A2 C
What is the type of modulation in which the modulating signal
varies the duration of the transmitted pulse?
A. Amplitude modulation
B. Frequency modulation
C. Pulse-width modulation
D. Pulse-height modulation
4BH 1B1 D
In a pulse-position modulation system, what parameter does the
modulating signal vary?
A. The number of pulses per second
B. Both the frequency and amplitude of the pulses
C. The duration of the pulses
D. The time at which each pulse occurs
4BH 1B2 A
Why is the transmitter peak power in a pulse modulation system
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
4BH 1B3 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
4BH 2A1 D
What digital code consists of elements having unequal
length?
A. ASCII
B. AX.25
C. Baudot
D. Morse code
4BH 2B1 C
What digital communications system is well suited for
meteor-scatter communications?
A. ACSSB
B. AMTOR
C. Packet radio
D. Spread spectrum
4BH 2B2 A
The International Organization for Standardization has developed
a seven-level reference model for packet-radio communications
structure. What level is responsible for the actual transmission
of data and handshaking signals?
A. The physical layer
B. The transport layer
C. The communications layer
D. The synchronization layer
4BH 2B3 B
The International Organization for Standardization has developed
a seven-level reference model for packet-radio communications
structure. What level arranges the bits into frames and controls
data flow?
A. The transport layer
B The link layer
C. The communications layer
D. The synchronization layer
4BH 2C1 C
What is one advantage of using the ASCII code, with its larger
character set, instead of Baudot code?
A. ASCII includes built-in error-correction features
B. ASCII characters contain fewer information bits than Baudot
characters
C. It is possible to transmit upper and lower case text
D. The larger character set allows store-and-forward control
characters to be added to a message
4BH 2D1 D
What type of error control system does Mode A AMTOR use?
A. Each character is sent twice
B. The receiving station checks the calculated frame check
sequence (FCS) against the transmitted FCS
C. Mode A AMTOR does not include an error control system
D. The receiving station automatically requests repeats
when needed
4BH 2D2 A
What type of error control system does Mode B AMTOR use?
A. Each character is sent twice
B. The receiving station checks the calculated frame check
sequence (FCS) against the transmitted FCS
C. Mode B AMTOR does not include an error control system
D. The receiving station automatically requests repeats
when needed
4BH 2E1 D
What is the duration of a 45-baud Baudot RTTY data pulse?
A. 11 milliseconds
B. 40 milliseconds
C. 31 milliseconds
D. 22 milliseconds
4BH 2E2 B
What is the duration of a 45-baud Baudot RTTY start pulse?
A. 11 milliseconds
B. 22 milliseconds
C. 31 milliseconds
D. 40 milliseconds
4BH 2E3 C
What is the duration of a 45-baud Baudot RTTY stop pulse?
A. 11 milliseconds
B. 18 milliseconds
C. 31 milliseconds
D. 40 milliseconds
4BH 2E4 B
What is the primary advantage of AMTOR over Baudot RTTY?
A. AMTOR characters contain fewer information bits than
Baudot characters
B. AMTOR includes an error detection system
C. Surplus radioteletype machines that use the AMTOR code
are readily available
D. Photographs can be transmitted using AMTOR
4BH 2F1 B
What is the necessary bandwidth of a 170-Hertz shift, 45-baud
Baudot emission F1B transmission?
A. 45 Hz
B. 250 Hz
C. 442 Hz
D. 600 Hz
4BH 2F2 B
What is the necessary bandwidth of a 170-Hertz shift, 45-baud
Baudot emission J2B transmission?
A. 45 Hz
B. 249 Hz
C. 442 Hz
D. 600 Hz
4BH 2F3 B
What is the necessary bandwidth of a 170-Hertz shift, 74-baud
Baudot emission F1B transmission?
A. 250 Hz
B. 278 Hz
C. 442 Hz
D. 600 Hz
4BH 2F4 B
What is the necessary bandwidth of a 170-Hertz shift, 74-baud
Baudot emission J2B transmission?
A. 250 Hz
B. 278 Hz
C. 442 Hz
D. 600 Hz
4BH 2F5 C
What is the necessary bandwidth of a 13-WPM international Morse
code emission A1A transmission?
A. Approximately 13 Hz
B. Approximately 26 Hz
C. Approximately 52 Hz
D. Approximately 104 Hz
4BH 2F6 C
What is the necessary bandwidth of a 13-WPM international Morse
code emission J2A transmission?
A. Approximately 13 Hz
B. Approximately 26 Hz
C. Approximately 52 Hz
D. Approximately 104 Hz
4BH 2F7 D
What is the necessary bandwidth of a 1000-Hertz frequency shift,
1200-baud ASCII emission F1D transmission?
A. 1000 Hz
B. 1200 Hz
C. 440 Hz
D. 2400 Hz
4BH 2F8 A
What is the necessary bandwidth of a 4800-Hertz frequency shift,
9600-baud ASCII emission F1D transmission?
A. 15.36 kHz
B. 9.6 kHz
C. 4.8 kHz
D. 5.76 kHz
4BH 2F9 A
What is the necessary bandwidth of a 4800-Hertz frequency shift,
9600-baud ASCII emission J2D transmission?
A. 15.36 kHz
B. 9.6 kHz
C. 4.8 kHz
D. 5.76 kHz
4BH 2F10 C
What is the necessary bandwidth of a 5-WPM international Morse
code emission A1A transmission?
A. Approximately 5 Hz
B. Approximately 10 Hz
C. Approximately 20 Hz
D. Approximately 40 Hz
4BH 2F11 C
What is the necessary bandwidth of a 5-WPM international Morse
code emission J2A transmission?
A. Approximately 5 Hz
B. Approximately 10 Hz
C. Approximately 20 Hz
D. Approximately 40 Hz
4BH 2F12 B
What is the necessary bandwidth of a 170-Hertz shift, 110-baud
ASCII emission F1B transmission?
A. 304 Hz
B. 314 Hz
C. 608 Hz
D. 628 Hz
4BH 2F13 B
What is the necessary bandwidth of a 170-Hertz shift, 110-baud
ASCII emission J2B transmission?
A. 304 Hz
B. 314 Hz
C. 608 Hz
D. 628 Hz
4BH 2F14 C
What is the necessary bandwidth of a 170-Hertz shift, 300-baud
ASCII emission F1D transmission?
A. 0 Hz
B. 0.3 kHz
C. 0.5 kHz
D. 1.0 kHz
4BH 2F15 C
What is the necessary bandwidth of a 170-Hertz shift, 300-baud
ASCII emission J2D transmission?
A. 0 Hz
B. 0.3 kHz
C. 0.5 kHz
D. 1.0 kHz
4BH 3.1 C
What is amplitude compandored single sideband?
A. Reception of single sideband with a conventional CW receiver
B. Reception of single sideband with a conventional FM receiver
C. Single sideband incorporating speech compression at the
transmitter and speech expansion at the receiver
D. Single sideband incorporating speech expansion at the
transmitter and speech compression at the receiver
4BH 3.2 A
What is meant by compandoring?
A. Compressing speech at the transmitter and expanding
it at the receiver
B. Using an audio-frequency signal to produce pulse-
length modulation
C. Combining amplitude and frequency modulation to
produce a single-sideband signal
D. Detecting and demodulating a single-sideband signal
by converting it to a pulse-modulated signal
4BH 3.3 A
What is the purpose of a pilot tone in an amplitude
compandored single sideband system?
A. It permits rapid tuning of a mobile receiver
B. It replaces the suppressed carrier at the receiver
C. It permits rapid change of frequency to escape high-powered
interference
D. It acts as a beacon to indicate the present propagation
characteristic of a band
4BH 3.4 D
What is the approximate frequency of the pilot tone in an
amplitude compandored single sideband system?
A. 1 kHz
B. 5 MHz
C. 455 kHz
D. 3 kHz
4BH 3.5 B
How many more voice transmissions can be packed into a
given frequency band for amplitude compandored single
sideband systems over conventional emission FM systems?
A. 2
B. 4
C. 8
D. 16
4BH 4.1 D
What term describes a wide-bandwidth communications system in
which the RF carrier varies according to some predetermined
sequence?
A. Amplitude compandored single sideband
B. AMTOR
C. Time-domain frequency modulation
D. Spread spectrum communication
4BH 4.2 A
What is the term used to describe a spread spectrum
communications system where the center frequency of a
conventional carrier is altered many times per second
in accordance with a pseudo-random list of channels?
A. Frequency hopping
B. Direct sequence
C. Time-domain frequency modulation
D. Frequency compandored spread spectrum
4BH 4.3 B
What term is used to describe a spread spectrum communications
system in which a very fast binary bit stream is used to shift
the phase of an RF carrier?
A. Frequency hopping
B. Direct sequence
C. Binary phase-shift keying
D. Phase compandored spread spectrum
4BH 5.1 D
What is the term for the amplitude of the maximum positive
excursion of a signal as viewed on an oscilloscope?
A. Peak to peak voltage
B. Inverse peak negative voltage
C. RMS voltage
D. Peak positive voltage
4BH 5.2 D
What is the term for the amplitude of the maximum negative
excursion of a signal as viewed on an oscilloscope?
A. Peak to peak voltage
B. Inverse peak positive voltage
C. RMS voltage
D. Peak negative voltage
4BH 6A1 A
What is the easiest voltage amplitude dimension to measure
by viewing a pure sine wave signal on an oscilloscope?
A. Peak to peak voltage
B. RMS voltage
C. Average voltage
D. DC voltage
4BH 6A2 B
What is the relationship between the peak-to-peak voltage and
the peak voltage amplitude in a symmetrical wave form?
A. 1:1
B. 2:1
C. 3:1
D. 4:1
4BH 6A3 A
What input-amplitude parameter is valuable in evaluating
the signal-handling capacity of a Class A amplifier?
A. Peak voltage
B. Average voltage
C. RMS voltage
D. Resting voltage
--------------------------------------------------
End of Subelement 4BH.