2-2
Turn the unit on, press the NAV Support Key to access
Config
.
Using the arrow keys, select the crossed tools icon
Config
and press
↵
Enter. Scroll through the list of
Global
,
Measurement
,
Channel
Plan
,
Sweep Receiver
, and
Diagnostics
to
Channel Plan
. Then
explore
Setup Channel Plan,
choosing NCTA_Plan to start
exploring. If your CATV system does not use this plan, refer to the
Channel Plan chapter see how to ‘learn’ your system. You can start
with NCTA_PLAN and edit individual channels.
With an appropriate selected plan or learned plan you can
immediately start exploring the measurement capabilities of the SAM
4040D.
Level and Frequency Measurements
Press Level to examine the carrier’s video and audio levels. At this
time, explore with the up/down arrow keys across the channel plan.
Press, on the keypad, Freq and Chan to change display views.
SAM 4040D offers several different level displays optimized to many
of the day-to-day tasks in maintaining your cable system:
Level Measurement Mode allows detailed display about a single
channel. The video and audio levels are displayed both in bar graph
and numeric form. The delta between audio and video level is also
computed. Wavetek’s digiCheck
power measurement algorithms
are used to accurately read continuous digital carrier. (see Section
3.3.4)
SCAN mode displays a graph of the level of all channels in the
current channel plan, either with or without audio and digital carriers.
This mode is very useful when first connecting to a test point. It
allows a technician to quickly get a general idea of what may be
going on with signal levels.
Tilt Measurement Mode provides the information needed to set the
equalization in an amplifier. Up to nine selected ‘tilt channels’ are
measured and displayed at the same time. These can be the pilot
carriers, or can be channels that are used in each band of the
operating cable network. The meter automatically calculates tilt
across these channels and displays their levels.
Hum Measurement
Press
Hum
to measure the CATV system’s hum component. Note
that it is best to make hum measurements without the AC adapter