User's Manual

ADCP-75-158 • Issue 1 • July 2003 • Section 2: Description
Page 2-19
© 2003, ADC Telecommunications, Inc.
6 LINEAR POWER AMPLIFIER
The Linear Power Amplifier (LPA), shown in Figure 2-9, works in conjunction with the STM to
amplify the forward path RF output signal. The STM is interfaced with the LPA through the
D-sub connectors and wiring harness located at the rear of the RU cabinet or RU mounting
shelf. The RF signal is passed to the LPA for amplification and then passed back to the STM for
filtering and output via the STM’s ANTENNA port. The STM also supplies DC power to the
LPA through the same interface.
6.1 Primary Components
The LPA consists of a fan and several electronic circuit board assemblies that are mounted
within a powder-paint coated sheet metal enclosure. The metal enclosure provides a mounting
point for the electronic components and also controls RF emissions. Except for the fan unit, the
electronic components are not user replaceable. The LPA is designed for use within the RU
outdoor cabinet or RU indoor mounting shelf. Except for the STM interface connector, all
controls, indicators, and switches are mounted on the LPA front panel for easy access. A
carrying handle is provided on the front of the LPA to facilitate installation and transport.
8 STANDBY Multi-colored LED
(green/yellow/red)
Indicates if the system is in the Normal state (off)
Standby state (blinking green), Test state (blink-
ing red), or Program Load state (blinking yel-
low). See Note.
9 HOST UNIT Multi-colored LED
(green/yellow/red)
Indicates if no alarm (green), a minor alarm (yel-
low), or a major alarm (red) is reported by the
HU. See Note.
10 STM Multi-colored LED
(green/yellow/red)
Indicates if the STM is normal (green) or faulty
(red). See Note.
11 PA Multi-colored LED
(green/yellow/red)
Indicates if the power amplifier is normal
(green), over temperature (yellow), has a fan fail-
ure (yellow), or is faulty (red). See Note.
12 VSWR Multi-colored LED
(green/yellow/red)
Indicates if the forward path VSWR is above
(red) or below (green) the fault threshold.
13 PORT 1/PORT 2 Multi-colored LED
(green/red)
Indicates if the forward/reverse path optical sig-
nal from the STM/HU are normal (green), if no
optical signals are detected (red), or if excessive
errors are detected (red). See Note.
14 ALARM IN MINOR
ALARM IN MAJOR
Screw-type terminal
connector (14–26
AWG)
Connection point for two external alarm inputs.
The door-open switch lead wires are typically
connected to the major alarm terminals.
15 ANTENNA N-type female RF
coaxial connector
Connection point for the antenna.
Note: A more detailed description of LED operation is provided in Section 5.
Table 2-4. Spectrum Transport Module User Interface, continued
REF
NO
USER INTERFACE
DESIGNATION
DEVICE
FUNCTIONAL
DESCRIPTION