User's Manual

THALES Communications
OIM
AHV1600-SYSTEM
Page 106
July 16/09
B. INTERNAL SUB-ASSEMBLIES
The AHV1600 Transceiver contains the following sub-assemblies:
– The Digital chassis:
•
••
•
Performs the High Intensity Radiated Field (HIRF) protection, internal module interconnection,
digital and management processor capacity and power supply distribution,
•
••
•
Provides the helicopter with the mechanical and electrical interfaces,
•
••
•
Provides the hardware support of the downloaded software’s.
– The radio module:
•
••
•
Performs the Radio Frequency (RF) signal emission, the Radio Frequency (RF) signal reception
and the Beat Frequency (BF) signal extraction.
C. FUNCTIONAL CHARACTERISTICS
(1) OPERATION DATA
•
••
•
Output signals characteristics : ARINC 429 standard
•
Radar Altimeter height : ARINC word label 164 and 165 (BNR and BCD)
• Radar Altimeter Status : ARINC word label 272
•
Timing between both word labels is described hereafter:
•
First ARINC 429 output (serial) : IRS1 TX HI (+) / IRS1 TX LO (-)
•
Second ARINC 429 output (serial) : IRS2 TX HI (+) / IRS2 TX LO (-)
•
ARINC 429 specification:
• Exchange: unidirectional asynchronous
•
Word format: 32 bits data transfer with LSB transmitted in first
•
Label format: 8 bits in octal coding from LSB position of the word
•
Parity format: 1 odd parity bit at MSB position of the word
• Inter word gap: 4 bits minimum
Note: on each word, the odd parity bit is always computed from the first 31 data bits of the word.
•
Bit duration : 80 µs
±
2 µs
•
Bit form factor : 40 µs
±
2 µs
Note : the bit duration corresponds to a low speed operation at 12.5 kbps.
•
••
•
ARINC signals Transmission speed : 12.5 kbps
•
••
•
Input signals : AID0, AID1, AID2, AID_P
•
Low level voltage
≤
+ 3.5 VDC with sink current < 2mA (logic state 1).
•
High level voltage
≥
+15.3 VDC with sink current < 1 mA (logic state 0).
• Maximum level voltage ≤ +32.2 V
DC
.