Lesson 3/Learning Event 2
millimeters, telegraph distortion test sets, impulse noise counters, noise
measuring sets, and telegraph transmission test sets.
b. Specialized test equipment.
Specialized test equipment needed by
circuit conditioners over and above the generalized test equipment include
envelope delay test sets, wave analyzers, X-Y recorders, spectrum analyzers,
and equalizers.
Although equalizers are corrective devices, they are
adjusted more by circuit conditioners than by technical controllers.
c. Types of test sets.
Wherever standard military test sets are
available, they should be used. However, where standard military items are
incapable of measuring parameters required by DCA schedules, commercial
items must be procured. Many of these commercial items are "off-the-shelf"
merchandise. Since a number of manufacturers produce satisfactory items for
this purpose, the list of items may vary from one station to another. When
selecting such sets, the primary considerations must be the capability to
measure the parameters in question, and reliability of operation.
Other
items, such as appearance, size, power requirements, mounting arrangements,
and placements of controls, are secondary considerations.
Learning Event 2: CORRECTIVE DEVICES.
The principal corrective device used to condition VF communication
circuits is an equalizer.
For maximum utility in circuits that may be
required to carry data and secure voice signals, the equalizer should be
capable of correcting for envelope delay as well as the usual function in VF
circuits for correcting for amplitude-frequency distortion.
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