General Information
The VHF Digital Link (VDL) Mode 2 is an ICAO standard developed by the Aeronautical Mobile Communications Panel (AMCP) providing data communication between aircraft and ground-based systems. Aeronautical VHF data links use the band 117.975 - 137 MHz assigned by the International Telecommunication Union.
Usage:
§ Data communication within the Aeronautical Telecommunication Network.
Mode Details
|
|
Item |
Value |
|
Standard |
Modulation |
DPSK |
|
|
Modulation order |
8 |
|
|
Bandwidth (Hz) |
25000 |
|
|
Symbol rate (Bd) |
10500 |
|
|
Coding |
Reed Solomon |
|
Demodulator Settings |
Demodulator |
DPSK 2,4,8 A/B |
|
|
Symbol rate (Bd) |
10500 |
|
|
SR tolerance (Bd) |
10 |
|
|
Modulation order |
8 |
|
|
Version |
A |
|
|
Min. burst length (s) |
0.003 |
|
|
Max. burst length (s) |
1.000 |
|
|
Min. pause length (s) |
0.001 |
|
|
6 | |
|
Features |
Demodulation |
yes |
|
|
Recognition |
yes |
|
|
Decoding |
yes |
|
|
Automatic Polarity Adjustment |
no |
|
|
Combination with other modems (modem list) |
yes |
|
Tuning |
The tuning frequency is the center of the signal’s frequency range | |
|
Frequencies |
136.900 MHz 136.975 MHz | |
Table 26: VDL 2
Figure 23: VDL 2 Spectrogram