General Information
FEC-A is a synchronous FEC system. This system was mainly used for military and diplomatic services as well as for news agencies. This modem system is also known as FEC-100(A).
Usage:
§ Transfer of textual information over HF.
Mode Details
|
|
Item |
Value |
|
Standard |
Modulation |
FSK |
|
|
Number of tones |
2 |
|
|
Shift (Hz) |
850 |
|
|
Bandwidth (Hz) |
1200 |
|
|
Symbol rate (Baud) |
144 |
|
|
Error correction |
Convolutional coding |
|
|
Alphabet |
ITA-2 |
|
Demodulator Settings |
Demodulator |
FSK 2 matched |
|
|
Symbol rate (Bd) |
145 |
|
|
SR tolerance (Bd) |
5 |
|
|
Shift (Hz) |
850 |
|
|
Shift tolerance (Hz) |
50 |
|
|
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 | |
Table 111: FEC-A
Figure 39: FEC-A Spectrogram