среда, 15 июля 2009 г.

CHINESE SERIAL MODEM - is the very interesting signal

Chinese Serial Modem
PSK-8, Br~1630

The signal is here

Author: SergUA6 6.0
Band Width ~1800 Hz
Low Range ~470 Hz, the shift is possible, recieveing is in SSB
Baud Rate ~1627 Hz, possibly that it is 1630 in reality
n-Ary (PSK/MPSK): PSK-8
Carrier frequency ~1415 Hz, the shift is possible, recieveing is in SSB
The modulation, in which the signal was recieved (RX mode): SSB

Sonograms


pic.1 The general look



pic.2 Manipulation speed



pic.3 The signal in 8th degree




Diagrams


pic.4 The phase constellation with accumulation



pic.5 The phase constellation in dynamic


CHINESE SERIAL MODEM - is the extremely interesting signal. As the sample the record restored by corrector is used.
It is difficult enough to believe, that the signal having so obvious OFDM signs and characters, is not OFDM signal in reality.

However the record quality is high enough and allows to identify PSK-8 with the very high
probablity.

The very difficult regular data structure is very strongly change the
spectrum, in that way, it is creating illusion of the multi-channel transmission.

However the examples of such signals are exist, and it should not
be a big surprise.

This signal is the very intresting one. And the detailed analysis of CHINESE SERIAL MODEM will be considered in the next blog post as separate article.