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3.7 Error Amplifier
The primary function of the error amplifier is to sample and amplify the signal distortion level generated by
the main amplifier. The error amplifier cancels out the distortion and IMD when the error signal is coupled
onto the main signal at the amplifier output. The matching signal levels from the error amplifier are
injected back into the main amplifier output reducing any distortion and cancellation of IMD. The error
amplifier is a balanced multistage class AB amplifier. It has 75 dB of gain, and produces up to 65 Watt
output. The amplifier operates on +27 Vdc and is mounted directly on a heat sink.
3.8 Amplifier Status Monitoring
In the main and error amplifier stages, all normal variations are automatically compensated for by the feed-
forward loop control. When large variations occur beyond the adjustment range of the loop control, a loop
fault will occur. The amplifier will be disabled, and the LED will be RED. The alarms will be sent via the
21-pin connector on the rear of the module to the sub-rack summary alarm board.
3.9 Amplifier Module Cooling
Each amplifier module has its own heat sinks. All main amplifier components are mounted to the heat sink.
Forced air-cooling is used to pull air across the heat sinks for operations in the sub-rack. The fans for this
forced air-cooling is located in the sub-rack assembly. The fans are mounted in the rear of the sub-rack
assembly. Air is pulled from the front of the amplifier and exhausted out of the back of the rack.
3.10 DC Power Distribution
Primary Vdc for the system is provided by the host system to the sub-rack assembly. The sub-rack supplies
the +27 Vdc to the amplifier module. The +27 Vdc is supplied directly through the sub-rack power
splitter/combiner board. The amplifier module has a DC/DC converter that converts the +27 Vdc to +12
Vdc, +5Vdc,
Section 4
Operating Instructions
4.1 Introduction
This section contains operating instructions for the MAF800-100S Cellular Amplifier System.
4.2 Function of Amplifier Module Controls
Primary +27 Vdc power for the MAF800-100S amplifiers is applied via the 50-amp circuit breaker on the
front panel of the amplifier. A reset switch is located below the LED on the front panel. This switch resets
the amplifier module in the event of a minor alarm. The front panel LED is a multi color LED that changes
from GREEN in normal operation to RED during major or AMBER during minor alarms.
6
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