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Functions of the AGC Module,
AGC
The AGC function continuously adjusts output attenuators and equalizers up to ± 4
dB, to keep the output level and tilt of the amplifier constant. This function runs in a
cycle of 6 minutes to save power. During each AGC tuning session, the AGC module
monitors 4 pilot levels and 10 selected frequencies, and when the amplifier detects
that the adjusting values of attenuator and equalizer are out of the ± 4 dB range, an
alarm activates on the LED indicators or ROSA Element Management system. See
page 3-16 for the descriptions of LED indicators. After each tuning task is completed,
the AGC module goes to sleep status for the rest of the cycle.
In AGC function, when all the high or low pilots and their backup pilots drop out,
the values of the output attenuator and equalizer are set back to those in effect before
the AGC function is performed. The AGC module stays in AGC mode, monitoring
the pilot levels and the 10 selected frequencies, in a cycle the same as in Standby
mode. However, the amplifier doesn‟t adjust the output attenuator and equalizer,
until the level of any of the 4 pilots goes back to its detected level range from 85 to
120 dBuV.
If the user switches the AGC function to Standby mode, or pulls the AGC module
out of the amplifier, the current values of output attenuator and equalizer remain. If
a new AGC module is installed into the amplifier, the values of output attenuator
and equalizer are set back to those in effect before the AGC function is performed,
and the AGC module continues with the AGC function.
Fixed Gain
The fixed gain function sets the amplifier to its nominal gain, and monitors the 4
pilot frequencies and the 10 selected frequencies, in a cycle the same as in Standby
mode.
4038501 Rev C
Continued
Operation
3-19
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