parameter requirements, the technician takes no further action. If the line
does not meet parameter requirements, the technician applies only that
amount of equalization needed to bring the line within parameters.
To go
beyond these requirements wastes time, effort, and money.
The principal
equipment that is used to make the amplitude-frequency response test is
included as part of Telephone Test Set AN/USM-181 (appendix A, section IV,
figure 2). The AN/USM-181 consists of the following items: Oscillator Model
HP 204B, AC Voltmeter Model HP 403B, and Patch Panel Model HP 353A.
a. Test arrangement.
The block diagram shown in figure 2-3 is a
typical test arrangement for determining frequency response.
The test is
made in each direction of transmission.
Each station will record
measurements on both send and receive sides of the circuit under test.
However, the test will be controlled by the technician on the receive side
of the circuit.
b. Recording of test data. Test data will be recorded on the frequency
response data sheet, figure 2-4. Analyzed data will be recorded in figure
3-3, Circuit Parameter Test Report (DD Form 1697).
(1) Connect the components of the AN/USM-181 to the circuit under
test as indicated in figure 2-3.
Any signaling SF units must be removed
from the circuit during the test.
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