LESSON 2
CLASSES OF SYNTHESIZERS
SCOPE.....................................Principles
of
direct
and
indirect
synthesizers; simplified block diagram
analysis of frequency synthesizers.
CREDIT HOURS..............................2
TEXT ASSIGNMENT...........................Attached Memorandum, para 2-1 thru 2-3
MATERIALS REQUIRED........................None
SUGGESTIONS...............................None
LESSON OBJECTIVES
When you have completed this lesson, you should:
1. Know that
the
two
main
classes
of
frequency
synthesizers
are
direct
and
indirect.
2. Know that the direct class furnishes a signal directly from a crystal-controlled
3. Know that the indirect class furnishes a signal from a variable-frequency
oscillator, which is indirectly stabilized by a crystal oscillator.
4. Know that the stability of the output signal from a direct-type frequency
synthesizer depends upon the stability of all crystals used to develop the signal.
5. Know that the stability of the output signal from an indirect-type frequency
synthesizer depends upon the stability of the reference crystal oscillator.
6. Know that a tactical radio set using a frequency synthesizer is normally a
transceiver.
7. Be able to identify individual frequency synthesizers used with fixed station
receivers and transmitters.
ATTACHED MEMORANDUM
2-1.
CLASSES OF SYNTHESIZERS
A frequency synthesizer is seldom an individual item; it is normally part of a
complete radio set.
Occasionally, specialized frequency synthesizers are made
available as individual items, but these are normally limited to special
applications, such as for converting existing radio sets, or for
327 L2
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