Cisco GainMaker Optoelectronic Node 1GHz with 65 86 MHz Split Installation Guide
Balancing the Reverse Path
correct RF signal level to inject.
In the example shown above, 19 dBmV + 20 dB = 39 dBmV. Therefore, you would
In the example shown above, 19 dBmV + 20 dB = 39 dBmV. Therefore, you would
set the signal generator output for + 39 dBmV.
Important:
Important:
When using a CW signal generator, inject at least two carriers, one at the low end
and one at the high end of the reverse bandpass. In a reverse system with a 5
MHz to 40 MHz bandpass, the low frequency carrier should be in the 5 MHz to
10 MHz range and the high frequency carrier should be in the 35 MHz to 40
MHz range.
The amplitude of the signal generator output can be set higher or lower than the
level specified by the calculation above, but the difference between the actual
output level and the level calculated above must be known. If the generator
output is x dB higher (or lower) than the level calculated, then the reference
(desired) level received at the headend or hub should also be x dB higher (or
lower) than the original headend reference level.
The station reverse input pad values are selected during the reverse system
design and are based on the need to minimize variations in return path losses for
the various reverse inputs. Do not permanently alter the values of the reverse
input pads without consulting a system designer.
The reverse input comes after the reverse injection point in the reverse path.
Temporarily replacing the design value reverse input pad on the port being
balanced with a 0 dB pad allows the reverse injection level and the receive levels
at the monitoring end to remain constant from amplifier to amplifier and from
port to port.
1 Insert the appropriate signal amplitude into the reverse injection test point. Refer
to the following illustration.
2 Proceed to To Complete Reverse Path Balancing.
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