User's Manual

NOTICE: (*) Typical performance under the following conditions (when applicable): Nominal
VSWR conditions (VSWR <1.5:1)
1.6
Theory of Operation
The SLR 1000 Repeater provides the radio frequency (RF) link between the repeater and the
subscriber radios. The repeater acquires inbound signals through its external receive (Rx) antenna and
then amplifies, filters and demodulates the signals into data or voice packets. From that point, the data
is either forwarded to the repeater’s transmitter to subscriber radios, and/or the data is delivered
through a wired interface for distribution to networked repeaters, consoles, or other networked
infrastructure.
The repeater consists of a single transceiver board.
•
The transceiver board is comprised of three subsystems, which are the Receiver subsystem,
Transmitter subsystem, and Station Control subsystem. At a high level, these subsystems are
further explained, as follows:
- The Receiver subsystem is a dual heterodyne Receiver which receives the RF signal from the
subscriber’s transmitter. It then converts the resulting final intermediate frequency (IF) from an
analog signal to that of a digital word in IQ signal format. Finally, the Receiver delivers the IQ
signal, through the SSI bus, to the Station Control subsystem for demodulation. Also, the
Receiver subsystem provides for its own metering and diagnostics through software, and self-
contained calibration (no field tuning is needed for the Receiver subsystem).
- The Transmitter subsystem converts a two-port base band data signal, sent over the SSI bus
from the Station Control subsystem, to an analog signal representation. The analog signal is
then modulated with a low-power RF transmitter carrier that is generated by the Exciter
subsystem. The power modulated RF carrier is then amplified and delivered to the antenna. The
Exciter subsystem constitutes the transmitter of the repeater. Also, the Exciter subsystem
provides its own metering and diagnostics through software, and a self-contained calibration (no
field tuning is needed for the Exciter subsystem).
- The heart of the Station Control subsystem is the Texas Instruments DM8148 Host/ DSP
processor. In general, the SCM controls the entire coordination of the repeater functions.
Specifically, the Station Control subsystem provides for the following functions:
+ Contains and runs the preloaded repeater software
+ Manages inbound and outbound RF and Audio traffic
+ Provides an on-board USB port for local configuring, alignment, and diagnostics through the
following applications:
• Radio Management Configuration Client (RM)
• Tuner application
• Repeater Diagnostic and Control (RDAC) software
+ Provides an Ethernet port for IP site connectivity and remote RDAC
+ Provides GPIO connectivity for third-party controller interfaces
+ Provides for analog repeater audio connectivity
+ Data and Control to the Receiver subsystem through the SPI and SSI respectively
+ Data and Control to the Exciter subsystem through the SPI and SSI respectively
+ Control of the Transmitter’s set power through the SPI
+ Configuration and fault management
+ Generates the internal station reference
MN003557A01-AA
Chapter
1: SLR 1000 Repeater
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Preliminary FCC Filing