(4) Test Various tests are continuously performed both on hardware and software elements, including voltage level timing, algorithms and discrete signals. the tranceiver status is displayed on the VDR and on the CFDIU. The functional test can be started from the tranceiver front panel with the two pushbutton switches.
R **ON A/C 051-099, 106-149, 201-299, 301-399, 401-499,
(4) Selftest
-The purpose of this test is to test the front panel LEDs and to test the functioning of the radio. The color of the LEDs in the fourth phase indicate the result of the selftest. The duration of the LED illumination is for reference only.
---------------------------------------------------------------------------| PHASE | LRU STATUS | CONTROL FAIL | ANTENNA FAIL | DURATION | ---------------------------------------------------------------------------| 1 | RED | RED | RED | 1-3 sec | | 2 | GREEN | RED | RED | 1-3 sec | | 3 | OFF | OFF | OFF | 1-3 sec | | 4 | GREEN | OFF | OFF | 20-40 sec | ---------------------------------------------------------------------------
R 1EFF : 001-049, 051-099, 101-149, 201-299, 1 23-12-00Page 36 1301-399, 401-499, 1Aug 01/05 1 1 1CES 1 **ON A/C 001-049, 101-105,
(5) Software loading mode The sofware program is loaded into a non-volatile memory from a program card when this card is inserted into tranceiver front panel. The front panel pushbutton switches and LCD display are used to control this operation.
**ON A/C ALL
B. VHF Antenna
(1)
Description (Ref. Fig. 011) The VHF antenna is a white blade antenna. It weighs 1.2 kg. This antenna is composed of:
-An aluminum base plate
-
A laminated radome
-
A duralinox leading edge
-
A C-type coaxial connector surrounded by a seal.
The antenna is connected to the transceiver by means of a coaxial
cable. It is screwed on to the fuselage. The attachment screws make
the electrical bonding.
(2)
Operation The VHF antenna, the height of which corresponds to a quarter of the wavelength, provides quasi-omnidirectional radiation. This antenna allows the transmission and reception of VHF signals over the 116 to 156 MHz frequency range. Its impedance is 50 ohms and its standing-wave ratio is < 2 over the 118 to 137 MHz VHF frequency range.
7. Operation
_________
R **ON A/C 001-049, 051-099, 101-149, 201-299, 301-399, 401-499,
A. Receive Function The antenna picks up the VHF radio-communication signals from the stations. These signals are transmitted to the transceiver by a coaxial cable. The transceiver, tuned on the frequency selected on one RMP (Ref. 23-13) demodulates the VHF received signals into AF signals. The AF signals are transmitted via the AMU to the audio equipment or SELCAL system.
1EFF : ALL 1 23-12-00Page 37 1 1 Aug 01/05 1 1 1CES 1
VHF Antenna Figure 011
1EFF : 1 1R 1CES ALL 1 11 1 23-12-00 Page 38 May 01/05
B. Transmit Function The AF signals from the microphones are transmitted to the VHF transceiver through the AMU. The VHF transceiver tuned on the frequency selected on one RMP transforms the AF signals into VHF modulated signals. The VHF signals are fed to the antenna by a coaxial cable. They are then transmitted to the various stations. A connection between the VHF transceiver and the SDAC enables to record the use of the VHF system in transmit mode. The connection is obtained through the PTT switch.
**ON A/C 151-199,
A. Receive Function The antenna picks up the VHF radio-communication signals from the stations. These signals are transmitted to the transceiver by a coaxial cable. In voice mode, the transceiver, tuned on the frequency selected on one RMP (Ref. 23-13) demodulates the VHF received signals into AF signals. The AF signals are transmitted via the AMU, to the audio equipment or SELCAL system. In data mode, the transceiver tuned on frequency selected on one MCDU (and transmitted to the transceiver through ARINC 429 HS bus), demodulates the VHF3 received signals into digital information, which is transmitted to the ATSU (through ARINC 429 HS bus).
B. Transmit Function In voice mode, the AF signals from the microphones are transmitted to the VHF transceiver through the AMU. The VHF transceiver tuned on the frequency selected on one RMP, transforms the AF signals into VHF modulated signals. The VHF signals are fed to the antenna by a coaxial cable. They are then transmitted to the various stations. A connection between the VHF transceiver and the SDAC enables to record the use of the VHF system in transmit mode. The connection is obtained through the KEY EVENT output information of the VHF Transceiver. In data mode, the digital information is transmitted from ATSU to VHF3 (tuned on the frequency selected on one MCDU and transmitted to the transceiver through ARINC 429 HS bus) which modulates it. The VHF signals are fed to the antenna by a coaxial cable. They are then transmitted to the various stations.
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