LESSON 1
PRACTICE EXERCISE
In each of the following exercises, select the ONE answer that BEST
completes the statement or answers the questions. Indicate your solution
by circling the letter opposite the correct answer in the subcourse
booklet.
1.
The gain of the amplifier shown in figure 2 of FM 11-671, Extract is
3 dB. If the input power rises to 2 mw and the output power rises to
4 mw, the gain of the amplifier is now
a.
0 dB.
b.
2 dB.
c.
3 dB.
d.
6 dB.
2.
The loss of a circuit is quoted at 30 dB, with an input level of 2
mw. The output level of the circuit is
a.
0.1 mw.
b.
0.002 mw.
c.
2,000 mw.
d.
60 mw.
3.
The standard reference level used in telephone work is 0 dBm.
This
level was chosen because it represents it
a.
complete absence of all power, thus making all level figures
positive with respect to the reference.
b.
average amount of power generated by the voice in a telephone
c.
threshold of hearing; that is, the point where you just begin to
become aware of sound.
d.
best
possible
balance
between
input
and
output
in
a
communication system for good understandability of voice.
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