5-1
SECTION 5 REVERSE SWEEP OPTION
5.1 INTRODUCTION
The Stealth sweep system is designed to be non-interfering. Hence
the name Stealth for something that is there and no one knows it
except the sweep technicians. In general terms, the sweep is set up to
measure existing signals, and insert sweep signals where there are no
service channels. The system is accurate and stable on the existing
signals because the Model 3ST transmitter is continuously monitoring
these signals in the headend and sending the information to the Model
3ST receiver at the field test point to compensate for level drift or
headend level tinkering.
This section provides detailed operation of the Model 3SRV Reverse
Sweep Option. Included are detailed descriptions of how to perform
reverse sweeping as well as interpret the various displays.
5.1.1 Wavetek Stealth Reverse Sweep Concept
The Stealth sweep follows a channel plan which contains information
on where channels exist and where sweep signals are inserted. For
forward sweeping, the channel plan is built through a process in which
the 3ST transmitter tunes through a standard (or HRC or IRC)
channel analog video line-up and looks for the presence of a signal on
the input. If a signal is present, it builds it into the plan as a TV
channel. The technican can then edit the plan and designate channels
as scrambled (sweep dwells longer at that frequency to ensure acquir-
ing the peak), or as digital (provided the 3SR has a digital option).
Further, he can review other specific channel-related information.
After identifying the existing channels, the technician builds sweep
points to automatically set up one to three sweep points in nonexistent
channels (video frequency, audio frequency and halfway in between).
Individual sweep points may also be added at any specific desired
frequency. The technician scrolls through the plan in the 'Edit
channel parameters' mode to make sure that the sweep points are set
so as not to intrude on any service channels. The sweep insertion point
should be at least 100 kHz from the edge of any channel.
Summary of Contents for 3SR
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