четверг, 21 мая 2009 г.

DIGTRX is the very interesting signal. Fresh analysis.

Author: SergUA6
DIGTRX signal.

Band Width ~1830-1850 Hz
Low Range ~300 Hz, shift is possible, receiving is in SSB
Baud Rate 122.5
Hz n-Ary (PSK/MPSK) special differencial PSK-9
Count of Carriers 8 perfectly visible freqeucnes of manipulation
Step between carriers 230 Hz
The modulation, in which the signal was recieved (RX mode) SSB

The example of the signal is here

pic.1 general look of the signal
pic.2 spectral differencies in the channels

pic.3 speed of manipulation
pic.4 the constellation in the channeles 1,3,4

pic.5 the constellation in the channel 5

pic.6 the constellation in the channels 5,6,7,8

pic. 7 generall organisation of change-overs

DIGTRX - it is the very interesting signal, in which special differential modulation DPSK-9 is used, a bit unexpectedly.
The signal is bright enough. In Signals Analyzer features are well visible both to manipulation as a whole, and to distinctions in channels. Here is the very interesting circuit of difference manipulation.
The general organisation is shown on
pic 7., it does not exclude change-over from a position +3 in -2(for example), but it allows to notice, that change-over from +4 to -4 has smaller vector's lengh than the others, that is already interesting in itself, besides, this change-over is also working(operating) and actively used.
pic6. it is possible to understand the reason of instability of the constellation in PSK-4 mode, it is well visible that this short change-over from +4 to -4 is exactly that "the disturber of calmness", which on the one hand imitates PSK-4, but on the other hand it does distract PSK-4.
Surely, this is the very interesting signal.