ARQ-M4-242

General Information

ARQ-M4-242 is a synchronous full duplex time-division multiplex system designed for low error-rate exchange of textual data between two stations of governmental authorities.

Usage:

§ Transfer of textual information over HF.

Mode Details

 

Item

Value

Standard

Modulation

FSK

 

Number of tones

2

 

Shift (Hz)

170

 

Bandwidth (Hz)

400

 

Symbol rate (Bd)

172 / 192

 

Alphabet

ITA-3

Demodulator Settings

Demodulator

FSK 2,3,4 discr.

 

Symbol rate (Bd)

192

 

SR tolerance (Bd)

2

 

Modulation order

2

 

Shift (Hz)

173

 

Shift tolerance (Hz)

10

 

Modem type

Synchronous

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 28: ARQ-M4-242

Figure 11: ARQ-M4-242 Spectrogram