1837 –Samuel Morse invented telegraph.
1858 –First telegraph cable across Atlantic (Canada – Ireland) 1876 – Alexander Graham Bell invented telephone.
1888 – Heinrich Hertz introduce electromagnetic field theory. 1897 – Marconi invented wireless telegraph.
1906 –Radio communication system was invented. 1923 –Television was invented.
1938 –Radar and microwave system was invented for World War II. 1950 –TDM was invented.
1956 –First telephone cable was installed across Atlantic. 1960 –Laser was invented
1962 – Satellite communication 1969 – Internet DARPA
1970 – Corning Glass invented optical fiber. 1975 – Digital telephone was introduced. 1985 – Facsimile machine.
1988 – Installation of fiber optic cable across Pacific and Atlantic. 1990 –World Wide Web and Digital Communication. 1998 – Digital Television.
Saturday, June 30, 2012
Vehicle-Protection Jammers (VPJs) against radio-controlled improvised explosive devices (`RCIEDs ´)
• Responsive VPJ (VPJ-R)
– With sufficiently fast reaction time upcoming RCIED-trigger signal can be detected and jammed before RCIED can be detonated
Advantages:
(i) Jamming signals are directly al located to potential trigger signals
(ii) Wide bands can be covered without excessive energy consumption
(iii) Even trigger signals at unexpected frequencies can be corrupted
Friday, June 29, 2012
The greatest threat to aircraft and helicopters comes from IR missiles.
The greatest threat to aircraft and helicopters comes from IR missiles. As these are not normally associated with radar guidance, aircrew get no warning of the impending danger unless they are lucky enough to either see the weapon being launched or in flight. The proliferation of IR missiles is high, if we look only at shoulder launched 'Manpad' systems the most numerous is the SA-7 with many hundreds of thousands having been produced. The US Stinger has been sold in numbers approaching 50,000 while the French Mistraal numbers 12,000 to 18 different countries. The following examples give an indication as to the success of passively guided IR weapons:
During 1977 to 1985 905 of all loses were to IR guided weapons. 4.4% were to radar guided weapons.
During the Gulf War 78% of all loses were to IR weapons.
Over the last 20 years only 10% of aircraft have been shot down by radar guided weapons.
During 1977 to 1985 905 of all loses were to IR guided weapons. 4.4% were to radar guided weapons.
During the Gulf War 78% of all loses were to IR weapons.
Over the last 20 years only 10% of aircraft have been shot down by radar guided weapons.
Friday, June 15, 2012
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