General Information
DUP-ARQ is a synchronous duplex teleprinter system with ARQ. This modem was used by the Ministry of Foreign Affairs in Hungary.
Usage:
§ Data communication over HF.
Mode Details
|
|
Item |
Value |
|
Standard |
Modulation |
FSK |
|
|
Number of tones |
2 |
|
|
Shift (Hz) |
170 |
|
|
Symbol rate (Baud) |
125 |
|
|
Coding |
7 bit parity |
|
|
Alphabet |
ITA-2 |
|
Demodulator Settings |
Demodulator |
FSK 2 matched |
|
|
Symbol rate (Bd) |
125 |
|
|
SR tolerance (Bd) |
0.1 |
|
|
Shift (Hz) |
170 |
|
|
Shift tolerance (Hz) |
10 |
|
|
Modem type |
Synchronous |
|
|
Min. burst length (s) |
0.245 |
|
|
Max. burst length (s) |
0.280 |
|
|
Min. pause length (s) |
0.260 |
|
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 | |
Table 108: DUP-ARQ
Figure 38: DUP-ARQ Spectrogram