AR 10043414, Operating And Service Manual, Page: 17 / 44

Rev A 1
1. GENERAL INFORMATION
1.1 GENERAL DESCRIPTION
The Model 25A250B is a self-contained, broadband solid-state amplifier designed for laboratory applications
where instantaneous bandwidth, high gain, and moderate power output are required. A
GAIN control, which
is conveniently located on the unit’s front panel, can be used to decrease the amplifier’s gain by 20 decibels
(dB) or more. Solid state technology is used exclusively to offer significant advantages in reliability and
cost. A Model 25A250B, used with a frequency-swept signal source, will provide 25 watts of swept power
output from 0.01–250 megahertz (MHz). Typical applications include antenna and component testing,
wattmeter calibration, and electromagnetic interference (EMI) susceptibility testing, as well as usage as a
driver for frequency multipliers and high-power amplifiers. The Model 25A250B can be operated locally by
using the unit’s front panel controls, or remotely by using the unit’s IEEE-488, RS-232 interface, USB, or
Ethernet interface.
Special features incorporated into the Model 25A250B include the following:
•
A Control Panel that allows both local and remote (via a computer interface) control of the amplifier
(including adjustment of the amplifier’s RF Gain during CW mode operation) and provides graphical
displays of the amplifier’s Forward and Reflected power levels.
•
A General Purpose Interface Bus (GPIB)/IEEE-488.2 interface for remote control of the amplifier’s
operating functions.
•
RS232 serial communications including both wire and fiber-optic ports for remote control.
•
USB Communication port for remote control.
•
Ethernet Communication port for remote control.
•
Protection is provided by DC current limiting, over-temperature shut down and RF power limiting.
1.2 SPECIFICATIONS
Refer to the AR RF/Microwave Instrumentation Data Sheet at the end of this section for detailed
specifications.
1.3 POWER SUPPLIES
The Model 25A250B contains one switching power supply. The input voltage range to the power supply is
90–264 VAC, 50/60Hz, selected automatically. The AC input power is approximately 200 watts.
PS1 has a +5 volt, standby supply for the A4 Control/Fault board and the A5 Interface board used for the
remote interfaces.
PS1 is a multiple output supply. The main +15V, 10A supplies voltage to the A10 Voltage Regulator board.
The –12 volts DC is supplied to the A1 module.
PS2 is a single output supply which pr28VDC to the RF module final stage and to the A10 Voltage
Regulator board.
Primary AC circuit protection is provided by the circuit breaker in the Power Entry Module.