General Information
SI-ARQ is an ARQ mode similar to SITOR for the exchange of teletype-data over a radio channel in a robust way.
Usage:
§ Basic maritime data communication over HF.
Mode Details
|
|
Item |
Value |
|
Standard |
Modulation |
FSK |
|
|
Number of tones |
2 |
|
|
Shift (Hz) |
170 |
|
|
Bandwidth (Hz) |
400 / 500 |
|
|
Symbol rate (Bd) |
96 / 192 |
|
|
Error correction |
ARQ |
|
|
Alphabet |
ITA-2 |
|
Demodulator Settings |
Demodulator |
FSK 2 matched |
|
|
Symbol rate (Bd) |
96 |
|
|
SR tolerance (Bd) |
1 |
|
|
Shift (Hz) |
170 |
|
|
Shift tolerance (Hz) |
5 |
|
|
Modem type |
Synchronous |
|
|
Min. burst length (s) |
0.217 |
|
|
Max. burst length (s) |
0.600 |
|
|
Min. pause length (s) |
0.061 |
|
Features |
Demodulation |
yes |
|
|
Recognition |
yes |
|
|
Decoding |
yes |
|
|
Automatic Polarity Adjustment |
yes |
|
|
Combination with other modems (modem list) |
yes |
|
Tuning |
The tuning frequency is the center of the signal | |
Table 189: SI-ARQ
Figure 65: SI-ARQ Spectrogram