cryptomaster
Спасибо за пояснение по ARQ-E, это частично объясняет, почему скорость в канале не
46 бод, а
46 с копейками:
Увеличить
Увеличить
Shift table should help in identifying certain ARQ-E-users:
46.15 Bd / 170 Hz UNID African user (Arabic alphabet)
72 Bd / 85 Hz German Police, German Border Guards
72 Bd / 400 Hz French MIL
85.71 Bd / 160 Hz German Air Force
96 Bd / 85 Hz German Police
96 Bd / 170 Hz German Police, German DIPLO*, German Intelligence*, Italian DIPLO*
96 Bd / 340 Hz Israeli Intelligence
96 Bd / 850 Hz Italian Intelligence
184.6 Bd /400 Hz French MIL
192 Bd /160 Hz French MIL
192 Bd /170 Hz German DIPLO*, possibly South African Intelligence*
192 Bd /190 Hz German Intelligence*
288 Bd / 190 Hz German Intelligence*
288 Bd / 340 Hz Israeli Intelligence
288 Bd / 400 Hz possibly Taiwanese Intelligence*
http://www.signals.taunus.de/FFT/ARQ-E.HTML
The ARQ-E duplex systems operate at speeds of
46.2, 48, 50, 64, 72, 86, 96, 144, 184.6, 192 and 288 Baud on the radio link.
ARQ-E synchronization may be started by the selection of a baud rate. An “AUTO” program start causes the automatic determination of the frequency shift and baud rate to be executed first. The signal polarity (USB or LSB sidebands) is automatically detected.
After synchronization to an ARQ-E system has been achieved, the detected repetition rate is displayed (4, 5 or 8 cycles). This parameter may give clues to the identity of the transmission.
If a continuously repeated character (often FFFF) is decoded whilst working in the ARQ-E mode, it is most likely an ARQ-E3 system being monitored. ARQ-E employs the ARQ-1A alphabet with parity checking which allows the detection of transmission errors.
Full duplex systems transmit a RQ character after having detected an erroneous character or in the presence of excessive signal distortions. The remote station subsequently repeats the last three, four or seven characters preceded by the RQ character.
To maintain synchronization between the two stations both transmitters operate continuously and send the idle bit pattern if no traffic is transmitted.
http://www.wavecom.ch 
