E8D Amplitude compandored
single-sideband (ACSSB); spread-spectrum
communications
E8D01
(C)
What is
amplitude compandored single-sideband?
A. Reception of single-sideband signal with a
conventional CW receiver
B. Reception of single-sideband signal with a
conventional FM receiver
C. Single-sideband signal
incorporating speech compression at the transmitter and speech expansion at the
receiver
D. Single-sideband signal incorporating speech
expansion at the transmitter and speech compression at the receiver
E8D02
(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
E8D03
(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 the band
E8D04
(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
E8D05
(B)
How
many more voice transmissions can be packed into a given frequency band for
amplitude-compandored single-sideband systems over conventional FM-phone
systems?
A. 2
B. 4
C. 8
D. 16
E8D06
(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
E8D07
(A)
What
spread-spectrum communications technique alters the center frequency of a
conventional carrier 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
E8D08
(B)
What
spread-spectrum communications technique uses a very fast binary bit stream to
shift the phase of an RF carrier?
A. Frequency hopping
B. Direct sequence
C. Binary phase-shift keying
D. Phase compandored spread-spectrum
E8D09
(C)
What
controls the spreading sequence of an amateur spread-spectrum transmission?
A. A frequency-agile linear amplifier
B. A crystal-controlled filter linked to a
high-speed crystal switching mechanism
C. A binary linear-feedback
shift register
D. A binary code which varies if propagation
changes
E8D10
(D)
Why are
spread-spectrum communications so resistant to interference?
A. Interfering signals are removed by a
frequency-agile crystal filter
B. Spread-spectrum transmitters use much higher
power than conventional carrier-frequency transmitters
C. Spread-spectrum transmitters can
"hunt" for the best carrier frequency to use within a given RF
spectrum
D. Only signals using the
correct spreading sequence are received
E8D11
(B)
Why do
spread-spectrum communications interfere so little with conventional
channelized communications in the same band?
A. A spread-spectrum transmitter avoids
channels within the band which are in use by conventional transmitters
B. Spread-spectrum signals
appear only as low-level noise in conventional receivers
C. Spread-spectrum signals change too rapidly
to be detected by conventional receivers
D. Special crystal filters are needed in
conventional receivers to detect spread-spectrum signals