LESSON 1
PRINCIPLES OF FM
SCOPE ....................................Principles of amplitude modulation (AM),
phase modulation (PM), and frequency
modulation
(FM);
effects
of
the
modulating
signal's
amplitude
and
frequency on the carrier wave; bandwidth
occupied by an FM signal.
CREDIT HOURS .............................2
TEXT ASSIGNMENT ..........................TM 11-668, para 1-15;
Attached Memorandum, para 1-1
MATERIALS REQUIRED .......................None
SUGGESTIONS ..............................None
LESSON OBJECTIVES
When you have completed this lesson, you will be able to:
1. Compute the needed carrier amplitude and frequency for an FM transmitter when
given the limiting conditions.
2.
Determine the modulation index and the carrier deviation for an FM transmitter.
3.
Determine the changes in signal bandwidth when the modulation index is changed.
4. Use the time-constant formulas to determine circuit response and the component
values that are needed for a particular response.
ATTACHED MEMORANDUM
1-1.
DEFINITIONS
The following definitions will be used in this lesson.
a. Frequency Deviation.
The amount by which a frequency-modulated wave either
increases or decreases from the center frequency.
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