User's Manual

P.G. TM0040AE
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 in each
band to the maximum composite level compatible with low intermodulation performance.
A-2 INSTALLATION
The AUTOSET board has four 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 a timed AGC mode where it tracks the
composite output power in each band and adjusts the attenuators to maintain maximum
output power. This mode continues for approximately 90 minutes until the system achieves
temperature stability.
At this time 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 limiter mode.
Each time the system (or amplifier) is repowered the setting cycle is repeated.