AR 0053007, Operating And Service Manual

Page: 69 / 86

Model 2500A225C
Rev A 45
3.4 CONTROL SYSTEM
3.4.1 A14 Control/Fault Board
The A14 Control/Fault board consists of one 16-bit microcontrollers and several other ICs that monitor and
indicate the status of the amplifier. Power is supplied using only a single 5-volt power supply. The board offers
the following:
Feature Quantity
Open drain outputs 4
Digital outputs 6
Digital inputs (5-volt tolerant) 24
Analog outputs 2
2-channel encoder input 1
Inputs for a keypad 6
Display connectors 1
Serial communication jacks 2
3.4.2 A15 Interface Board
The A15 Interface board connects the remote control ports to the A14 controller.
3.4.3 A16 ALC
The A16 Level Control Assembly performs the following functions:
• Provides automatic level control of the amplifier’s output when placed in ALC mode.
•
Limits RF input level to the amplifier when forward or reflected power levels exceed specified limits.
•
Drives forward and reflective indicators on the display panel.
3.5 SAMPLE PORTS
The signals appearing at the sample ports produce a level of approxi3dBm at 2500W. Both forward
and reverse signals have the same scaling at this point. The sample ports are measured during final alignment
of the amplifier and a correction table is provided with enough measured points to adequately characterize the
sample ports across the full bandwidth of the amplifier. When used with a power meter, sample ports are
intended to be a general guide to the forward and reverse power being produced. If more accuracy or calibration
is required, an external directional coupler is recommended.