Cisco Prisma II bdr Dig Rev 2 1 Dual Mux Sys for High Density Installations Guía De Instalación
78-741939-01 Rev C Reverse Balancing the Node with the Enhanced Digital Reverse Modules
3-9
Reverse Balancing Procedure,
Continued
Note: For the location of forward output test point of each port, refer to
the illustrations showing the reverse test points and accessories on the RF
launch amplifier given earlier in this chapter.
Important: To calculate the correct signal level to inject, simply add the
reverse input level (from the design print) to the insertion loss of the
forward output test point.
Formula:
Reverse input + Insertion loss = Signal generator setting
Example:
Reverse input = 17 dBmV
Insertion loss = 20 dBmV
Result: Signal generator setting=17 dBmV + 20 dB = 37 dBmV
Notes:
•
Formula:
Reverse input + Insertion loss = Signal generator setting
Example:
Reverse input = 17 dBmV
Insertion loss = 20 dBmV
Result: Signal generator setting=17 dBmV + 20 dB = 37 dBmV
Notes:
•
The ADC full-scale (100%) level for a single CW carrier is +46 dBmV.
This is the level at which the ADC begins clipping.
•
The reverse attenuator (pad) and reverse equalizer in the Model 6940
4-Port Node and Model 6944 Optical Node is selected during the
reverse system design, and it is based on the drive level into the digital
module which is determined by system performance requirements, type
and quantity of return carriers, etc. Consult data sheet to determine
proper operational level.
3.
Verify the level of the reverse output test point. This output level leaves
the RF launch amplifier via the coaxial cable to the 2:1 enhanced
multiplexing digital module input (Use a SMB to F test cable).
4.
Have the person in the headend refer to the headend system design and
set the output of the bdr receiver to the specified output level. See the
instruction guide that was shipped with bdr receiver for setup
procedures.
5.
Close the housing. Refer to Closing the Housing in Section B of
Chapter 2.