понедельник, 9 ноября 2009 г.

OFDM: CIS-112 signal

CIS-112
Br~22.22, Sh~25.6, Ch-112 + 1 Pilot, pi/4 DQPSK


Author: SergUA6
Band Width ~3000-3100 Hz
Low Range ~340-320 Hz, shift is possible, recieveing in SSB
Baud Rate ~22.22 Hz
n-Ary (PSK/MPSK) pi/4 DQPSK
Count of Carriers 56, 112
Step between carriers ~25.6 Hz
Pilot tone(s) one pilot ~3305 Hz, shift is possible, recieveing in SSB
RX mode SSB

Sonograms:

pic.1 General view


pic.2 Spectrum's detalization


Diagrams:

pic.3 Preamble 1, detalization.

pic.4 Detalization of the signal's part with 56 channeles

pic.5 The signal itself, 112 channeles.


CIS-112 is the very interesting signal. We classify it to CIS, because CIS signals have the upper pilot with frequency 3300 Hertz. It is hard to identify this signal and it's parameters by classical methods. Other tools are necessary, SA OFDM module allows to define parameters of the signal precisely enough and fast, to define signal key parametres. The signal has been sent by lakisan2008, this signal has an interesting preamble 1, where all tones are modulated. In the whole signal pi/4 DPSK is used, which is standardly enough for OFDM. In the signal , which has been sent by RadioKoteg, PSK-2 is used in all channels, within the limits of the main manipulation pi/4 DQPSK ofcourse. Besides in this record, there are single symbols with 56 channels, about each 72 symbol