ARQ FAE mode :
This new ARQ mode is located, for the modulation, between the FS1045A DTM and DBM ARQ modes. For the protocol it is located between the FS1045A DTM and DBM modes and PAX/PAX2 modes.
"ARQ" is worth for "Automatic Repetition reQuest" and "FAE" for "Fast Acknowledged Exchange".
It is a bilateral mode, which means that messages can be transmitted from A to B and from B to A, in full duplex (protocol one, not physical one). The ACK or NAK answer can be accompanied or not by a message (as in PAX/PAX2).
The characters exchanged are 8 bits length so as to permit exchange in all ASCII-ANSI languages (English, French, German, Russian...), but not those with ideograms (as Japonese).
Contrary to DBM mode, the length of the frame is variable and depends of the message length (as in DTM mode). But as DBM mode, the blocks are not redundantly repeated and there is a global message interleaving (but with a variable ID).
ARQ FAE modulation description :
Baud rate : 125
Rough speed : maximum: 148 wpm (for 30 characters length message) or 184 wpm (for 63 characters length message)
Use speed : maximum in unilateral: 88 wpm (for 30 characters length message) and 125 wpm (for 63 characters length message)
: maximum in bilateral: 120 wpm (for 30 characters length message) and 164 wpm (for 63 characters length message)
Modulation : FSK 8 tones (3 bits)
Reception mode : only one side (USB or LSB), USB is recommended
Character set : ASCII +ANSI characters (8 bits)
Shape of pulse : rectangular
Space between tones : 250 Hz,
Bandwidth : 2000 Hz,
Demodulation : non-coherent,
Synchronization : automatic using the signal
Coding : Golay
Interleaving : yes (global within a block of data (message + CRC))
Drift tolerance : 10 to 20 Hz/mn according to signal-to-noise ratio,
Pmean/Ppeak : 1
Lowest S/N : - 6.5 dB (- 8.5 dB with many repetitions)
A "soft decision" Memory Arq is implemented. It makes the transmission more reliable (see details in the ARQ FAE protocol).
+Good for networking
+More sensitvie compared to 300 baud packet
Automactic Link Establishment
FFT Screen Shot
Mode Audio Sample