5-8
5.2.1 Reverse Sweep Insertion Level
The reverse sweep can be used to efficiently align the reverse path,
while monitoring the frequency response. proper alignment requires
a reference that is relevant to typical sweep insertion point losses. A
common practice is to store the reference when reverse sweeping
from the node (active containing reverse laser). As the technician
proceeds downstream from node to amplifier to amplifier, changes in
insertion point losses may be compensated by changing either the
output level or test point compensation. The active component
(reverse laser or reverse amplifier) typically specifies the optimum
input level for the device in terms of an analog video carrier level
measured with a 300 kHz resolution bandwidth. Just as the sweep is
inserted at a lower level in the forward path (for a discussion of this,
see 3ST Transmitter Installation, page 5-13), the reverse sweep may
also be inserted at a lower level. The target for the return level signal
arriving at the passive device should be approximately 10 dB below
the optimum input level specified by the manufacturer. This makes
it even less likely that the sweep signal will interfere with the digital
services in the reverse band.
From the manufacturer's specifications for the active device, deter-
Summary of Contents for 3SR
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