Forward Balancing - C-COR Flex Max901e Equipment Manual

Forward Balancing

ALC operating range for NTSC or QAM channel pilot operation prior to performing
the forward balancing procedure
The ALC setup range in Flex Max901e amplifiers originally featured a pilot frequency setup range of
+2/-6 dB at standard output levels. To achieve this range, amplifiers shipped with a factory-installed
ALC PAD (see table below). Effective September 22, 2006, C-COR changed the factory-set ALC setup
range for these products to feature an improved range of +5/-3 dB at standard output levels. As of that
date, Flex Max901e amplifiers began shipping with a new factory-installed ALC PAD (see table below).
Model
Flex Max901e
Trunk—1GHz
T&B same tilt
Flex Max901e
Trunk—1 GHz
T&B different tilt
Flex Max901e
Bridger—1GHz
1. QAM pilots operate 6dB down from the NTSC pilots.
C-COR currently offers three QAM pilot frequencies above 499.00 MHz: 609.00 MHz, 645.00 MHz,
and 711.00 MHz. QAM pilot frequencies are centered on standard NTSC channel frequencies.
Model
Flex Max901e Trunk—1GHz
FMTEG8x—Optimized for 1GHz
Trunk and bridger different tilt
Flex Max901e Trunk—1 GHz
FMTED5x—Ideal as drop-in spares
Trunk and bridger same tilt
Flex Max901e Bridger—1GHz
The ALC PAD location controls NTSC and QAM channel operating range setup. The Flex Max901e
ships with a factory-installed NPB series PAD in this location for standard NTSC operation at C-COR
recommended pilot levels. Refer to the tables above for exact NPB PAD values.
Changing the value of the ALC PAD readjusts the operating range of the ALC to ensure pilot level control
over C-COR's specified temperature range. The same ALC balancing techniques can be used for both
analog and digital operation if the QAM channel occupies the same spectrum as the NTSC channel.
1502154 Rev D
ALC PAD Value Before 9/22/2006
NTSC Pilot
Factory-Installed
PAD
8dB
8dB
8dB
For optimum operation of ALC, the value of the ALC PAD should be changed in direct
relationship to recommended C-COR forward output pilot level.
– NTSC example: if your system design increases the output pilot level of the 1 GHz
configuration trunk 3 dB above the nominal output (37 dBm), increase the
factory-installed 9 dB ALC PAD by 3 dB, to 12dB, for an optimum ALC operating range.
Changing the ALC PAD allows a QAM signal to operate 6 dB lower than the NTSC channels.
– QAM example: If the QAM channels are set at – 6 dB from the NTSC channels, lower
the ALC PAD by 6dB.
1
QAM Pilot
Technician-Installed Factory-Installed
PAD
2dB
2dB
2dB
ALC PAD Values for QAM Pilots Above 499.00MHz
QAM Reference Pilot Level
32dBmV
31dBmV
39dBmV
ALC PAD Value After 9/22/2006
NTSC Pilot QAM Pilot
Technician-Installed
PAD PAD
6dB 0dB
9dB 3dB
13dB 7dB
ALC PAD Value Factory-Installed
4dB
3dB
9dB
Configuration
1
5
5-15