User's Manual

Model 1150A DVOR
2-6 Rev. - November, 2008
This document contains proprietary information and such information may not be disclosed
to others for any purposes without written permission from SELEX Sistemi Integrati Inc.
Refer to Figure 2-3. The Remote Maintenance System Processor (RMS) handles all command, control,
communications and information for the DVOR system.
A monitor antenna located on any radial in the far field provides an RF signal which is equally divided and sent to
the VOR monitors for processing and analysis.
The VOR monitor CCA works independently from the transmitter and from each other; however, the alarm control
features of both monitors can be organized to function in a logical AND or logical OR arrangement.
The Local Control Unit (LCU) is responsible for turning off the transmitters and transferring from Main to Standby
transmitters. The LCU contains hardware logic that acts on alarm inputs from the Monitors. The LCU has two
controls to each transmitter to remove radiation in case of out-of-tolerance conditions. The LCU is responsible for
controlling the transfer relays and reporting the current state of the relays as to which transmitter is connected to the
antenna.
The transmitter cabinet contains the assemblies needed to control the electronic switching of the sideband antennas.
2.3.1.1
Electronics Cabinet (Unit 1)
The VOR electronics cabinet assembly contains all of the electronic assemblies that generate, control, and monitor
the DVOR modulated radio frequencies. The cabinet contains three separate card cage assemblies that hold the
transmitter and RMS modules. It provides the means to physically secure the modules within the electronics cabinet
and provides for the interconnection of the modules. Attached, but independent from it, are the five coaxial latching
relays mounted to the middle card cage directly behind the RF monitor assembly. The relays are latched by
applying a ground pulse to either the latch or release coil. The relays are powered from a common 28 volt source.
The relays switch the ten RF inputs (main and standby) between the antenna system and the dummy loads. They
also provide DC logic signals which are used by the Monitors and Audio Generators to sense which transmitter
system is connected to the antenna system. The DC logic signal is supplied to the Audio Generator to enable
commutator switching signals and identification to be applied from the on-air Audio Generator CCA.
2.3.2
System Block Diagram Theory
Refer to Figure 2-2 and Figure 2-3. The DVOR system block diagram depicts the main components (both optional
and required) of a functional station and identifies primary signal, control and voltage paths within the station.
The DVOR system is contained in an electronics cabinet assembly. Connected to this DVOR cabinet are the
PMDT, carrier antenna, sideband antennas, field monitor antenna, and optional backup batteries.
The electronics cabinet is next broken down into its main components which are a Local Control Unit (LCU), RMS,
main and standby transmitters, VOR monitor CCAs, RF monitor, changeover relays, battery charger power
subsystems (BCPS).
The LCU contains the displays that provide a visual indication of the status of the VOR system along with control to
change the operational states of the DVOR.
The RMS group handles all command, control, communications, and information for the station.
The main transmitter consists of a frequency synthesizer assembly, CSB power amplifier assembly, directional
coupler, audio generator CCA, and two sideband generators. Supplying the voltage for the main transmitter is a
stand-alone battery charger power subsystem, and a Low Voltage Power Supply (LVPS).
The frequency synthesizer assembly contains three CCAs. They are the carrier CCA, the Sideband CCA and the
Interconnect CCA. This assembly produces the three interrelated RF signals used by the DVOR. The on-channel
carrier RF signal drives the CSB power amplifier assembly. The upper and lower sideband RF signals drive the two
sideband generator assemblies.