General Information
MD-674 is a military synchronous FSK modem.
Usage:
§ Data communication over HF.
Mode Details
|
|
Item |
Value |
|
Standard |
Modulation |
FSK |
|
|
Number of tones |
2 |
|
|
Symbol rate (Bd) |
50 … 150 |
|
|
Error correction |
ARQ |
|
|
Alphabet |
ITA-2 / ITA-5 |
|
Demodulator Settings |
Demodulator |
FSK 2,3,4 discr. |
|
|
Symbol rate (Bd) |
100 |
|
|
SR tolerance (Bd) |
5 |
|
|
Modulation order |
2 |
|
|
Shift (Hz) |
85 |
|
|
Shift tolerance (Hz) |
10 |
|
|
Modem type |
Synchronous |
|
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 | |
Table 11: MD-674
Figure 13: MD-674 Spectrogram