C-COR Flex Max901e, Equipment Manual

Page: 72 / 172

5
5-16 Flex Max901e 1GHz Trunk and Bridger Amplifiers 1502154 Rev D
Forward Balancing Requirements
Make sure that the following requirements are met before you start to balance:
■
The system map is marked with amplifier output levels for bandedge frequencies.
■
Forward balancing carriers, set at the proper levels, are injected into the cable network
from the headend.
■
One forward balancing carrier is available at a lower bandedge.
■
One forward balancing carrier is available at a higher bandedge.
■
RAW DC, B+, and B+ ripple voltages are within acceptable range (refer to Voltage Testing
on page 5-5 as necessary).
■
All tap outlets, ends of feeder cables, and unused active RF ports are terminated with a 75
Ω
impedance.
■
Unscrambled ALC carriers are injected into the system at the assigned frequency for the
amplifier (if ALC is to be used).
■
The correct ALC PAD value is installed for NTSC or QAM channel ALC operation. The ALC
PAD
ships with factory-installed NPB series PADs for standard NTSC operation. Refer to
the tables on page 5-15 for exact NPB PAD values.
■
Preceding amplifiers have been properly balanced and provide the desired forward band
signals to the amplifier for forward balancing.
■
Flex Max901e trunk and bridgers amplifiers can be configured with the appropriate plug-in
accessories for 1GHz operation
or for use as spares in 750/870MHz systems. Refer to Power
Supply Configuration beginning on page 5-3.
CAUTION RF input signal levels greater than +45 dBmV @ 1 NTSC channel loading
can damage amplifier active components. Derate maximum input level according to
actual channel loading (for example, +26 dBmV @ 79 NTSC channel loading)
(+26 dBmV = +86 dBµV).
Note “System” values are those recommended values shown on the system map.
“Measured” values are the signal levels actually measured at the amplifier.
Note While SEQ-1G and SCS-1G plug-in accessories will address all bandwidths up to
1 GHz, you may wish to reuse your current equalizers and cable simulators until you
expand your system to 1 GHz. Refer to the bulleted items in Step 3 under Upgrade
Considerations on page 3-2 to determine which plug-ins can be reused.