118 9 November 2001 Transmitters
Setting the Transmitter
for Manual Mode
(DT-TX Series)
In manual mode, you can set the RF drive level to the laser
using the manual gain control.
DT-QTX transmitters do not
offer AGC.
If you plan to use AGC, go to “Setting Up AGC” on
page 120.
Set the transmitter to manual mode as follows:
When signal levels in the
200-TX return path change
frequently due to ingress or
scheduled addition or deletion
of channels, the AGC adjusts
the RF drive level, causing the
RF level out of the receiver to
change. To prevent this
condition, operate the
transmitter in manual mode.
1. Toggle the AGC/MAN switch down for manual mode.
2. Find the optimum RF drive level for the laser by referring
to the RF input level listed in the transmitter
specifications. Use the level that corresponds to the
transmitter’s channel loading.
3. Connect a spectrum analyzer to the RF drive level
monitor test point (on TX front panel).
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