User's Manual

P. G. TM0060
A-2
A-1 GENERAL
The AUTOSET optional gain control board installs on the jumper pins normally used for
manual setting of the gain control attenuators referred to in Paragraph 4.2.
When installed the AUTOSET board automatically limits the amplifier output power to the
maximum composite level compatible with low intermodulation performance.
A-2 INSTALLATION
The AUTOSET board has three jumpers which are set depending on whether the
amplifier is being used as an IN-LINE or ANTENNA amplifier. An IN-LINE amplifier
normally passes power to downlink amplifiers and is set to a slightly lower power level to
minimize cascading of IM products. The jumpers are set in accordance with Figure
A-1.
A-3 OPERATION
The AUTOSET controls each individual amplifier on a stand-alone basis. The AUTOSET
system has two modes of operation.
When initially powered the AUTOSET goes into an AGC mode where it tracks the
composite output power and adjusts the attenuator to maintain maximum output power.
This mode continues for approximately 90 minutes until the system achieves temperature
stability.
At this point the AUTOSET switches to a LIMITER mode in which it only adds attenuation
if the power input increases above the final setting value. This eliminates the system
hunting which might interact with system power control or cause near/far loss of signal.
If however power in the systems is increased by the addition of more channels the gain
will adjust downward to avoid distortion products.
The AUTOSET system can be configured to operate in a continuous AGC mode by
installing the “AM” shunt. In this mode, the AUTOSET operates in AGC mode indefinitely
and will not switch to a LIMITED mode.
Each time the system (or amplifier) is repowered the setting cycle is repeated.