STUDY EXERCISES
In each of the following exercises, select the ONE answer that BEST completes
the statement or answers the question.
Indicate your solution by circling the
letter opposite the correct answer in the subcourse booklet.
1. Many
current
items
of
communication
equipment
contain
frequency
synthesizers. The function of a frequency synthesizer is to
a.
prevent radio interference.
b.
reduce radio interference by 10 percent.
c.
multiplex several hundred telephone channels.
d.
produce several frequencies from one frequency source or a minimum
number of sources.
2. Assume that a 7-kHz signal is being modulated by a 300-Hz signal in an
unbalanced modulator. What are the four output signal frequencies?
a.
7 kHz, 3 kHz, 700 Hz, 300 Hz
b.
7.3 kHz, 7 kHz, 6.7 kHz, 300 Hz
c.
14 kHz, 7.3 kHz, 600 Hz, 300 Hz
d.
7.3 kHz, 3.7 kHz, 700 Hz, 300 Hz
3. A balanced modulator with an input of 140 and 1,600 kHz will produce an
output of
a.
1,460 and 1,600 kHz.
b.
1,460 and 1,740 kHz.
c.
140, 1,400, 1,600, and 1,700 kHz.
d.
140, 1,460, 1,640, and 1,740 kHz.
4. The synthesizing method most likely to be used to provide the carrier
frequencies in a multichannel telephone system is the
a.
addition method.
c.
basic modulation method.
b.
heterodyne method.
d.
harmonic generation method.
5.
The synthesizing method that produces a single synthesized signal is the
a.
heterodyne method.
c.
harmonic generation method.
b.
subtraction method.
d.
unbalanced modulator method.
327 L1
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