воскресенье, 29 ноября 2009 г.

FSK: Italian Military 1200 FSK-2.

Italian Military 1200
FSK-2

Author: SergUA6
Band Width ~ 1400-1500 Hz
Low Range ~ 1000 HZ, shift is possible, recievein is in SSB
Baud Rate 1200 Hz
Count of Carriers 2 manipulation frequency, the are not distinguishable on the spectrum
Step between carriers 800 Hz
RX mode SSB

Sonograms

pic.1 General view

pic.2 Detalization

pic.3 Manipulation speed

Diagrams:
pic.4 Precise spacing

pic.5 Unique feature of Italian Mil 1200 FSK-2

Italian Mil - Does not have obvious distinctive characteristics, but... Basically on such speeds, as a rule, frequency manipulation without phase rupture is used. But this signal is formed by another way. Classically, speed 1200, and spacing is 800, in this sense it same as well as AX.25 1200 in way of it's creation, but not in way of protocols. In that sense, it is unique enough feature, and it is possible to use this unqiue feature at an identification of this signal. With SA VMW help interesting enough feature of this signal is detected. This feature is shown on pic. 5 - almost regular changing of polarity through eight clock ticks (bit). That is a good distinctive characteristic.