The ALC Mode menu lets you perform the following:
Go to the leveling menu (select the ALC mode
of operation).
Go to the attenuation menu (decouple the at-
tenuator, if equipped, from the ALC system
and set the power level and attenuation).
Select either the front panel or rear panel ex-
ternal ALC input.
Internal Leveling
This is the normal (default) leveling mode. Output
power is sensed by the internal detector in the
681XXA . The detector output signal is fed back to
the ALC circuitry to adjust the output power level.
Internal ALC is selected from the leveling menu.
To go to the Leveling Menu from the ALC Mode
menu, press
Leveling Menu
. The Leveling Menu,
shown below, is displayed.
To select internal ALC, press
Internal
.
Pressing one of the other leveling menu soft-keys
External Detector
,
Power Meter
, or
Fixed Gain
will turn off internal leveling.
Press
Previous Menu
to return to the ALC Mode
menu.
External Leveling
In external leveling, the output power from the
681XXA is detected by an external detector or power
meter. The signal from the detector or power meter
is returned to the ALC circuitry. The ALC adjusts
the output power to keep the power level constant
at the point of detection. The external ALC source
input is selected from the leveling menu.
LOCAL (FRONT
LEVELING
PANEL) OPERATION
OPERATIONS
681XXA OM
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