Application Notes: Reverse Sweep and Balance
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NOTE: Select “func” and “7” to enter the Test Point
compensation. There is a toggle button to select forward or
reverse Test Point compensation.
Before You Leave the Headend
On the receiver select (CONFIGURE; SWEEP RECEIVER) and set the
forward sweep telemetry frequency to be the same as the Tx and/or Rx. Also
set the reverse sweep insertion and telemetry levels as close to the system
specifications as possible, taking into consideration insertion losses.
NOTE: Sweep and telemetry levels >15 dB above the
recommended input could cause return laser clipping and
erroneous balancing and sweep traces. This depends
upon the type of laser and return hybrids used.
Put in "Single User" mode if using the Tx for reverse sweeping, or in
"Multiple User" mode if using the Rx. Be sure the Tx is in the sweep mode
and the reverse is enabled.
Reverse Balancing and Sweeping
TIP: The quickest way to determine if your field unit has
reverse capability is to verify that there are two connections
on the top of the field unit.
First, balance the forward path and press "Sweep" to verify all is well, then
proceed with reverse.
Check the sweep in both directions. Change the sweep direction on the
receiver to reverse by using the left diamond key or selecting the following
sequence: (Configure; Sweep Receiver; Sweep Direction).
NOTE: The NS-6 or DDC-20 is necessary for firmware
version 8.5 or earlier. A summation network for return path
sweeping is not necessary for versions 9.x or later. There
must be a place to inject the sweep, which will make its
way to the Tx or Rx. Record the reverse telemetry level,
recommended reverse input, and test point loss. A reverse
sweep reference can also be taken at this time by selecting
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