Figure 1-7.
Single-tone interference test, block diagram.
b. Recording of test data. Readings obtained in the test are recorded
in the single-tone interference data sheet, figure 1-8.
Explanations
showing how to determine translated levels are shown below.
The maximum
permitted level of interfering tone is taken from the appropriate DCA
parameter.
(1) Table II of appendix A (Circuit Parameters), refers to
characteristics h and i under S, V, and D codes, and determines the maximum
acceptable level of single-tone interference for the type of service (code)
and mileage of the circuit under test. This value need be determined only
once and retained in station records for future tests.
(2) Slowly sweep the FREQUENCY control of the 302A through the
frequency range of the circuit under test. If any peaks are noted above the
acceptable level, record for each peak the frequency and absolute level. If
the technician wishes to listen to the restored interfering signal, he can
do so with the MODE SELECTOR switch set at NORMAL while listening with a
headset connected to the OUTPUT coaxial jack.
(3) Record the absolute power level indicated by the 302A and correct
the reading to a point of zero relative level by allowing for the relative
level of the interface at which the measurement was made.
Example:
An absolute power level of -40 dBm is measured.
The normal
transmission level at the
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