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Technology Stocks : Interdigital Communication(IDCC)

IDCC 358.04

+3.6%

Nov 25 3:59 PM EST

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To: Gus who wrote (3443)	1/20/2000 1:02:00 AM
From: Gus	Read Replies (1) of 5195

This is a link to a Spread Spectrum site that should be useful to anyone who wants to delve more deeply into the spread spectrum foundations of 2G CDMA, 3G CDMA2000 and 3G WCDMA. sss-mag.com Note that Hedy Lamarr died the other day at the age of 86. She is generally credited with the first spread spectrum patent - Patent No. 2,292,387. Early spark gap "Wireless era" transmitters actually used Spread Spectrum, since their RF bandwidths were much wider than their information bandwidth. The first intentional use of "Spread Spectrum" was probably by Armstrong in the late '20's or early '30's with wideband FM. The real impetus for Spread Spectrum came with World War II, however. Both the allies and the Axis powers experimented with simple Spread Spectrum systems. Much of what was done is still shrouded in secrecy, however. The first publically available patent on Spread Spectrum came from Hedy Lamarr (see "Secret Communications Technique" Patent ). Most of the work done in Spread Spectrum throughout the 50's, '60's and '70's was heavily backed by the military and drwoned in secrecy. The GPS system is now the worlds largest single Spread Spectrum system. Most of the details on GPS are now public information (see "The Geographer's Craft Project," The University of Texas at Austin). Spread Spectrum was first used for commercial purposes in the 1980's when Equitorial Communications of Mountain View, CA used Direct Sequence for multiple access communications over synchronous satellite transponders. Later in the '80's the US FCC opened up the ISM frequency bands for unlicensed Spread Spectrum communications (see Spread Spectrum Technology). There is very little historical information relative to Spread Spectrum on the Internet, but we present below a few of the links we found sss-mag.com

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