LESSON 2
AMPLITUDE MODULATION
SCOPE.....................................Systems, methods, and levels of modula-
tion; AF amplifiers, speech amplifiers;
modulator stages; speech limiting.
CREDIT HOURS..............................2
TEXT ASSIGNMENT...........................TM 11-665, para 69-82
MATERIALS REQUIRED........................None
SUGGESTIONS...............................None
LESSON OBJECTIVES
When you have completed this lesson, you will be able to:
1. Explain the principles of amplitude modulation.
2. Categorize the systems, methods, and levels of modulation.
3. Explain how RF and AF amplifiers are used in AM radio transmitters.
4. Explain how voice waves are changed to audio voltages, and amplified.
5. Explain how speech clipping is used to improve intelligibility.
DNI CORRECTIONS TO TM 11-665
Page 111, para 71a(l), line 41, change "5,000.5 kc" to: 5,005 kc.
Page 134, para 79d(l)(a), formula, change "Rp" to rp.
Page 144, para 81c(2), first sentence, change "V1 and V2" to V2 and V3.
LESSON 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. If the modulation of a 500-watt RF carrier is reduced from 100 percent to 70
percent, sideband power is reduced by approximately
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