MD-674

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