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Page 3-4
GNS 400W Series Maintenance Manual
Rev. A
190-00356-05
3.3 NAV
BOARD
The Nav Board contains the processor-controlled navigation receiver for VOR and Localizer
Signals from 108.00 MHz to 117.95 MHz in 50 kHz increments (200 channels). The Nav Board
performs the following functions:
•
Tunes a VOR or localizer frequency as commanded by the Main Processor.
•
Communicates VOR/LOC receiver sub-system status to the Main Processor.
•
Communicates VOR radial or localizer deviation, TO/FROM flag state and navigation
flag state to the Main Processor.
•
Drives horizontal deviation, flag and TO/FROM electrical outputs.
•
Receives Glideslope data from the Main Board to be sent out in ARINC 429 format.
•
Toggles the VOR/LOC identifier filter as commanded by the Main Processor.
•
Communicates to the Main Processor the detection of a remote frequency transfer key
press.
•
Drives electrical outputs for OBI.
•
Channels a remote DME if connected to the VOR/LOC Receiver Board.
•
Transmits ARINC 429 labels.
•
Receives ARINC 429 labels.
•
Provides signal pass-through for G/S flags and drivers to NAV Board Connectors.
3.4 GLIDESLOPE
RECEIVER
The Glideslope Receiver operates from 329.15 MHz to 335.00 MHz in 150 kHz increments (40
Glideslope channels). The Glideslope Receiver includes conventional RF, IF, and drives vertical
deviation and flags.
3.5
WAAS GPS RECEIVER
The WAAS GPS Receiver is a twelve channel parallel receiver that is capable of tracking and
using up to twelve visible satellites for position, velocity, and time calculations.
3.6
INVERTER BOARD
The Inverter Board supplies high voltage for display operation.
