FRIDAY SURPRISE: Your cel phone and its amazing connection to Hollywood
Today's cel phone technologies
rely on something called "spread spectrum," which is a fancy way of
saying "frequency hopping." In spread spectrum, a data stream - in
this case a voice - is transmitted using radio waves whose carrier
rapidly switches between many frequencies, using a prearranged
sequence known to both transmitter and receiver.
The reason the spread spectrum is so important - aside from being resistant to interference and very difficult to intercept - is because it makes more efficient use of scarce bandwidth. Spread spectrum makes it possible to carry more information - more conversations - amongst a limited number of frequencies.
But this use is very recent. Prior to the invention of the cel phone, frequency hopping was used to make military radio transmissions more secure. Using frequency hopping makes it far more difficult for an enemy to intercept your signal, and to use direction finders to pinpoint your location. Of course, it isn't just for voice! Frequency hopping makes it possible to have radio-control munitions, such as bombs and torpedoes, that your enemy can't jam into uselessness.
Now as useful as this is, one would think that the concept originated deep in some Pentagon think tank - but you'd be wrong! The idea came from the fertile mind of a beautiful woman, the actress Hedy Lamarr.
I'll let you read the articles below to find out about her valuable contribution to the world of communications technology!
Female Inventors: Hedy Lamarr
HEDY LAMARR: The Inventor of Frequency Hopping
Did You Know...about Hedy Lamarr?
Hedy Lamarr - from Wikipedia, the free encyclopedia
-=[ Grant ]=-
The reason the spread spectrum is so important - aside from being resistant to interference and very difficult to intercept - is because it makes more efficient use of scarce bandwidth. Spread spectrum makes it possible to carry more information - more conversations - amongst a limited number of frequencies.
But this use is very recent. Prior to the invention of the cel phone, frequency hopping was used to make military radio transmissions more secure. Using frequency hopping makes it far more difficult for an enemy to intercept your signal, and to use direction finders to pinpoint your location. Of course, it isn't just for voice! Frequency hopping makes it possible to have radio-control munitions, such as bombs and torpedoes, that your enemy can't jam into uselessness.
Now as useful as this is, one would think that the concept originated deep in some Pentagon think tank - but you'd be wrong! The idea came from the fertile mind of a beautiful woman, the actress Hedy Lamarr.
I'll let you read the articles below to find out about her valuable contribution to the world of communications technology!
Female Inventors: Hedy Lamarr
HEDY LAMARR: The Inventor of Frequency Hopping
Did You Know...about Hedy Lamarr?
Hedy Lamarr - from Wikipedia, the free encyclopedia
-=[ Grant ]=-
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