4-6
Figure 4-3 shows the Tilt display. Use the
LO
and
HI
soft keys to
select the LO and HI pilot channels for your Tilt adjustment.
Use the icons in this menu as follows:
The LO or HI icon will darken as either is selected.
Pressing this Icon brings up the following three useful
functions, then returns the main Tilt Menu.
Reference Level allows you to use the up/down arrow keys
to make discrete adjustments to the reference Level within
in pre-set range(+/-).
Scale allows you to adjust the dB/div on the vertical scales,
using the up/down arrow keys to scroll through the pre-set
values for best presentation on the screen.
Establishes an optimized AutoScale presentation, based on
the previous two settings.
NOTE: The
Reference Value
level is limited by the units selected
and the
Scale
setting.
The Tilt adjustment uses amplifier gain to compensate for the
attenuation of signals moving through the cable. Higher frequencies
are attenuated more than lower frequencies. This accounts for the
slope of the line in Figure 4-3. Tilt mode simplifies the actual
balancing by displaying a bar graph with a representation of up to
nine video carrier levels. Tilt adjustment compensates for unequal
attenuation, so that each channel reaches a customer with about the
same gain.
Information displayed in Figure 4-3 is as follows:
•
High and low carrier frequencies
•
High and low carrier levels
•
Tilt
measurement
•
Reference level and scale
•
Test point compensation (appears only if a non-zero value is
programmed during setup).
A cable system is designed for unity gain, and the output level of
each type of amplifier (trunk, bridger/line extender) should be set or