Honeywell International Inc. RTA-50D Manuale Utente
MAINTENANCE MANUAL
965-1696
(3)
The 1,200 or 2,400-Hz tones sent by the MU or CMU modulate the amplitude of the VHF
carrier generated by the VDR. This modulated signal is a DSB-AM signal whose amplitude is
modulated at 2,400 bps. The MU/CMU controls the access to the channel and initiates the
transmission of a message by a data key line discrete input to the VDR. The MU/CMU also
controls the data link channel selection through one of the low-speed (13 Kbps) ARINC 429
tuning inputs. Mode 0 operation is backward compatible with legacy ARINC 716 radios.
carrier generated by the VDR. This modulated signal is a DSB-AM signal whose amplitude is
modulated at 2,400 bps. The MU/CMU controls the access to the channel and initiates the
transmission of a message by a data key line discrete input to the VDR. The MU/CMU also
controls the data link channel selection through one of the low-speed (13 Kbps) ARINC 429
tuning inputs. Mode 0 operation is backward compatible with legacy ARINC 716 radios.
C.
Mode A Data (Subtask 23-20-59-870-014-A01)
(1)
Mode A allows the RTA-50D VDR to exchange downlink and uplink POA data messages with
an Airbus ATSU or an ARINC 758 CMU through a transmit/receive pair of 100 Kbps ARINC
429 digital interfaces instead of the analog audio interfaces used by Mode 0.
an Airbus ATSU or an ARINC 758 CMU through a transmit/receive pair of 100 Kbps ARINC
429 digital interfaces instead of the analog audio interfaces used by Mode 0.
(2)
The downlink message data bits transferred to the VDR modulate the RF carrier at a rate of
2,400 bps using the same DSB-AM MSK modulation scheme used in Mode 0. The difference
is that the MSK modem functionality resides in the RTA-50D VDR.
2,400 bps using the same DSB-AM MSK modulation scheme used in Mode 0. The difference
is that the MSK modem functionality resides in the RTA-50D VDR.
(3)
The VDR also controls when to access the channel to transmit data. The channel access
protocol is the same CSMA employed by the MU/CMU in Mode 0 operation. The data link
channel selection is still controlled by the ATSU/CMU, but channel selection messages are
exchanged through the same high-speed ARINC 429 interface used to exchange POA
messages which simplifies wiring.
protocol is the same CSMA employed by the MU/CMU in Mode 0 operation. The data link
channel selection is still controlled by the ATSU/CMU, but channel selection messages are
exchanged through the same high-speed ARINC 429 interface used to exchange POA
messages which simplifies wiring.
D.
VDL Mode 2 (Subtask 23-20-59-870-015-A01)
(1)
The newest VHF data link communication mode is VDL Mode 2. VDL Mode 2 is the term
used to describe a suite of air/ground protocols that increases the data rate of the air/ground
link to 31,500 bps.
used to describe a suite of air/ground protocols that increases the data rate of the air/ground
link to 31,500 bps.
(2)
VDL Mode 2 allows the transition from character-oriented ACARS protocols for end-to-end
delivery of messages to one that uses bit-oriented ATN protocols using the same VHF ground
and aircraft radios. The RTA-50D VDR Mode 2 capability supports the transmission and
reception of standard ACARS messages such as those generated by FANS A and FANS 1
applications using a protocol referred to as AOA.
delivery of messages to one that uses bit-oriented ATN protocols using the same VHF ground
and aircraft radios. The RTA-50D VDR Mode 2 capability supports the transmission and
reception of standard ACARS messages such as those generated by FANS A and FANS 1
applications using a protocol referred to as AOA.
(3)
The RTA-50D VDR Mode 2 capability also supports the transmission and reception of
bit-oriented ATN application messages such as CPDLC. The delivery of FANS A over AOA
and CPDLC over ATN/VDL Mode 2 is supported concurrently. The set of VDL Mode 2
protocols consist of the physical layer protocol, channel access protocol, data link service and
management protocol, and Mode 2 network access protocol. The physical layer protocol
includes the modulation, data rate, and forward error correction techniques used to transmit
data over the air/ground link.
bit-oriented ATN application messages such as CPDLC. The delivery of FANS A over AOA
and CPDLC over ATN/VDL Mode 2 is supported concurrently. The set of VDL Mode 2
protocols consist of the physical layer protocol, channel access protocol, data link service and
management protocol, and Mode 2 network access protocol. The physical layer protocol
includes the modulation, data rate, and forward error correction techniques used to transmit
data over the air/ground link.
(4)
The channel access protocol is the method that allows multiple aircraft to communicate
with the ground stations on the same frequency. The data link service and management
protocol includes procedures to establish, maintain and hand-off an air/ground link, and ensure
error-free delivery of messages. The network access protocol is the interface between users
and the Mode 2 air/ground link service providers. As in Mode A, only the physical layer and
channel access protocols are performed by the RTA-50D VDR while the data link service and
management, and the network access protocols are performed by the CMU.
with the ground stations on the same frequency. The data link service and management
protocol includes procedures to establish, maintain and hand-off an air/ground link, and ensure
error-free delivery of messages. The network access protocol is the interface between users
and the Mode 2 air/ground link service providers. As in Mode A, only the physical layer and
channel access protocols are performed by the RTA-50D VDR while the data link service and
management, and the network access protocols are performed by the CMU.
(5)
The VDL Mode 2 physical layer protocol employs a bit transmission rate of 31,500 bps over
the air/ground link on a single 25-kHz channel. The increased utilization of the 25-kHz
channel is achieved by use of a bandwidth modulation scheme known as D8PSK. A D8PSK
transmitter transmits a carrier whose phase is modulated by the data. The phase can be 0, 45,
90, 135, 180, 225, 270, or 315 degrees. The rate at which the carrier phase is changed is
the modulation rate.
the air/ground link on a single 25-kHz channel. The increased utilization of the 25-kHz
channel is achieved by use of a bandwidth modulation scheme known as D8PSK. A D8PSK
transmitter transmits a carrier whose phase is modulated by the data. The phase can be 0, 45,
90, 135, 180, 225, 270, or 315 degrees. The rate at which the carrier phase is changed is
the modulation rate.
EFFECTIVITY
ALL
23-20-59
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1 Mar 2011
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