ARQ-6-90

General Information

ARQ-6-90 is an ARQ mode similar to SITOR for the exchange of teletype-data over a radio channel in a robust way.

Usage:

§ Basic data communication over HF.

Mode Details

 

Item

Value

Standard

Modulation

FSK

 

Number of tones

2

 

Shift (Hz)

400

 

Bandwidth (Hz)

600

 

Symbol rate (Bd)

200

 

Error correction

ARQ

 

Alphabet

CCIR-476

Demodulator Settings

Demodulator

FSK 2 matched

 

Symbol rate (Bd)

200

 

SR tolerance (Bd)

5

 

Shift (Hz)

400

 

Shift tolerance (Hz)

20

 

Modem type

Synchronous

 

Min. burst length (s)

0.065

 

Max. burst length (s)

0.260

 

Min. pause length (s)

0.200

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 10: ARQ-6-90

Figure 4: ARQ-6-90 Spectrogram