User's Manual

Table Of Contents
Page 3–62
18 September 2007
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
eNfusion™ HSD-128 High-speed Data Terminal
(e) Antenna Subsystem RF Interface Multi-Channel
Several external RF parameters (such as cable losses and antenna gain), that
must be delimited to ensure proper operation, dictate the HSD performance
requirements.
Table 3–33 defines these parameters and their expected values.
(f) WOW Pin Wiring Multi-Channel
These Weight-On-Wheel (WOW) discretes are wired only if equivalent
information is not strapped as being available to the SDU on an ARINC 429 input
[for example, IRS or the Centralized Fault Display System (CFDS)].
WOW wiring, for the HSD, is optional for system operation as the HSD already
receives speed information for Doppler correction. However, if WOW wiring is
not wired, normal maintenance must be disabled when speed or Doppler
readings are greater than zero.
The WOW1 and WOW2 pins are either left open circuit or they are connected to
the airframe DC ground. The WOW Program Select (PGM) pin is either left open
circuit or is connected to the Forward Address Common. The three ground states,
defined for any pin are:
OPN: Open circuit
AFG: Airframe DC Ground
FAC: Fwd Address Common (TP7K)
Resolve any conflict between WOW1 and WOW2 by assuming the aircraft is
“in-air.” The interpretation of the state of the WOW1 and WOW2 pins is defined
by the state of the WOW program select pin. Refer to
Table 3–34 for details.
1. Multi-Channel Configurations
Labeled as WOW1, WOW2, and WOW Program Select, these discretes are
wired only if equivalent information is not strapped as being available to the
SDU on an ARINC 429 input [for example, IRS or the Centralized Fault
Display System (CFDS)].
Table 3–33. RF Parameters Definition Multi-Channel
Parameter Min. Value (dB) Max. Value (dB)
Antenna Gain 8 17
Antenna—DLNA Loss 0.1 0.3
DLNA Gain 53 60
DLNA Noise Figure 1.5 1.8
DLNA—HSD-128 (BP12), including
cables and splitter (Rx) Total Loss
019
DLNA—HSD-X (BP5), including
cables and splitter (Rx) Total Loss
524
HSD-128—Antenna (Tx) Loss 1 2.5
DLNA Insertion Loss (Tx to Antenna
Port)
–0.8