4-7
adjusted to be as close to the same level. The amplifiers are set up
with specified levels for signals at the high and low end of the
spectrum, used for Automatic Gain Control (AGC) or Automatic
Slope Control (ASC), respectively. In the amplifier balancing
process, these signals are measured and adjusted to specification.
In practice, before adjusting compensation of the amp, first check
that there are no problems in the system requiring repair. Gain
control affects all frequencies about equally; but slope control affects
lower frequencies more than the high end
To balance the amplifier for Tilt:
Select the Tilt display, and then select the HI Pilot channel.
•
Observe the nine Tilt channels by pressing the
Tilt
Measurement
Mode key. To include or exclude a channel in the nine Tilt
channels, you must choose desired video carriers as Tilt
Channels in the
Edit Channel Plan
portion of the
Config,
Channel Plan
menus.
•
Use the up/down arrow keys to adjust the reference level of the
graph.
•
Adjust amplifier Tilt as follows:
1. Switch, on the amplifier, AGC and ASC OFF.
2. Adjust the high pilot channel to the specified level , using the
Manual Gain control.
3. Adjust the low pilot channel to specified level using manual
Slope control.
4. Due to interaction between these controls, repeat the
process until you have the prescribed balance.
5. Switch AGC and ASC ON, and wait briefly, to be sure AGC
and ASC maintain that balance.