ARQ-N

General Information

ARQ-E is a synchronous dual channel ARQ mode. This system was used by Italian diplomatic services.

Usage:

§ Transfer of textual information over HF.

Mode Details

 

Item

Value

Standard

Modulation

FSK

 

Number of tones

2

 

Shift (Hz)

850

 

Symbol rate (Bd)

96

 

Error correction

ARQ

 

Repetition cycles (char)

4,5,8

 

Alphabet

ITA-2P

Demodulator Settings

Demodulator

FSK 2 matched

 

Symbol rate (Bd)

96

 

SR tolerance (Bd)

5

 

Shift (Hz)

850

 

Shift tolerance (Hz)

20

 

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 34: ARQ-N

Figure 13: ARQ-N Spectrogram